Skip to main content

2024 | Buch

Recent Research on Geotechnical Engineering, Remote Sensing, Geophysics and Earthquake Seismology

Proceedings of the 1st MedGU, Istanbul 2021 (Volume 3)

herausgegeben von: Attila Çiner, Zeynal Abiddin Ergüler, Mourad Bezzeghoud, Mustafa Ustuner, Mehdi Eshagh, Hesham El-Askary, Arkoprovo Biswas, Luca Gasperini, Klaus-Günter Hinzen, Murat Karakus, Cesare Comina, Ali Karrech, Alina Polonia, Helder I. Chaminé

Verlag: Springer Nature Switzerland

Buchreihe : Advances in Science, Technology & Innovation

insite
SUCHEN

Über dieses Buch

This edited book is based on the accepted papers for presentation at the 1st MedGU Annual Meeting, Istanbul, 2021. With five parts spanning a large spectrum of geological, geotechnical, and geophysical topics, this book presents a series of newest research studies that are nowadays relevant to Middle East, Mediterranean region, and Africa.

The book includes the latest research studies on seismic hazard and risk assessment, earthquake geodesy, seismotectonics, archaeoseismology and active faulting, well logging methods, geodesy and exploration/theoretical geophysics, geological engineering, geotechnical engineering and geoenvironment, geo-informatics, remote sensing and geohazards, basement architecture and potential data, and numerical and analytical methods in mining sciences and geomechanics.

Inhaltsverzeichnis

Frontmatter

Geological Engineering, Geotechnical Engineering and Geoenvironment

Frontmatter
Analysis of the Causes of Deformation of the Stabilized Mixture During Its Floating

The article deals with the basic characteristics of the stabilized mixture in connection with its subsequent use in the restoration of the landscape (brownfields). The former open-cast mine was chosen as a model locality. The hydraulic way deposited the stabilized mixture. Two flue gas desulphurization systems were applied in parallel at the site: the desulphurization by the semi-dry absorption method and the fluidized bed combustion method. The mineralogical composition of the stabilized mixture was analyzed. When the stabilized mixture is deposited, some significant deformation phenomena are observed in its mass. Therefore, a basic analysis of their causes was carried out. From previous observations, the leading cause of deformation changes is the variability of deposited mixture and differences in float cycles between individual storage. Also, another cause of deformation is mainly related to volume changes associated with the stabilization and its re-flooding with water in the following storage phase.

Jiri Kostal, Petr Cernoch
Geotechnical Properties of Artificially Produced Soils

The natural structure of the soil formations shows complex features due to its heterogeneous structure. For this reason, soil behavior should be defined clearly according to mechanical and physical parameters. However, sometimes irregularities of soil grains affect the experimental results in terms of shape and structure. In this study, an artificial granular material is produced thanks to three-dimensional printing technology to solve this problem. First, the printing process of five different soil grains is completed with PLA-based filament due to standard sieve openings, after the scanning process is completed with Agisoft Metashape software. In addition, the high plastic silt or sodium polyacrylate gel is added into the granular material mixtures to provide cohesion in the soil structure. Therefore, various soil mixtures are formed and classified in poorly graded or well-graded granular soils in addition to finer content. Then, physical parameters are determined by laboratory experiments such as specific gravity, sieve and hydrometer analysis, and consistency limits. At the same time, mechanical properties are obtained via the shear box test as an internal friction angle and maximum shear stress. After selecting the appropriate parameters in line with the results of experiments, the efficiency of produced samples with different physical forms will be evaluated.

Serpil Aktaş, Burak Evirgen
Classification Artificial Intelligence Algorithms Coupled with Clustering Algorithms: A Potential Technique to Consider for Predicting Soil Liquefaction Phenomena

Predictions of soil liquefaction phenomena under seismic loads have been investigated through available deterministic and statistical methods. However, it isn’t easy to develop a model considering all the independent soil variables. To overcome this limitation, this paper demonstrates that combining two artificial intelligence (AI) techniques could be worthwhile to assess soil liquefaction susceptibility based on the cone penetration test (CPT) data. So far, there has never been a study that used AI algorithms for soil clustering in liquefaction problems. Only a few studies compared the usability and performance of the prediction algorithms. At first, the data is clustered, and then only the cluster representatives are used for the prediction algorithms—the first technique uses the k-medoids clustering algorithm. The second uses AI algorithms such as artificial neural network (ANN), support vector machine (SVM), and random forest decision trees (RFDT) to predict the liquefaction susceptibility of soil. All three classification models indicate that the liquefaction susceptibility of the incompressible deposits with depthless critical layer is high compared to other clusters. This paper has demonstrated the usefulness of the clustering approach. The clustering model presented in this study can be a shortcut and simpler to apply than the conventional AI methods based on classification algorithms. The findings of the present work contribute to the artificial intelligence scientific revolution in the scope of the prediction models.

Mouad Kachiche, Abdelaziz Mridekh, Mohamed E. Bouhaddioui, Jaouad Dabounou, Atika Fahmi
Estimation of Site Response Characteristics by a Comparative Study of Numerical Modeling in Adapazarı City Basin, Turkey

In Turkey, earthquakes are likely the most prominent natural disaster threat. Also, severe earth tremors are typical in the Marmara region, where the sedimentary basin of Adapazarı takes its place. The study discusses the seismic site response problem considering one-dimensional earthquake wave propagation. To assist the engineers in improving a trustable site response model (for geotechnical earthquake studies) considering elastic base layers that underline deep depths of alluvial deposits. Thus, six site models, at different levels and stratifications, are built and calibrated regarding a closer relationship between soil and site conditions to simulate them for Dynamic Site Response Analyses (DSRAs) in a comparative analytical study. The essential governing parameters of the seismic response problem are the base depth, layers number, soil and bedrock properties (densities and shear wave velocities with depth), and input seismic excitations. The results of DSRAs are present in comparative graphical forms regarding Peak Ground Acceleration (PGA) and pseudo-spectral acceleration (PSA). In conclusion, the Engineering Seismic Base Layer (ESBL) model is not the ideal scenario, but it is still possible to use it for practical benefits. An efficient ESBL numerical model provides a solid basis for prediction and introductory studies and helps engineers feel more confident in earthquake-resistant structure design, remarkably when the dynamic soil-structure interaction problem is addressed.

Eyad Niruz Ually, Erkan Çelebi, Fatih Göktepe
Preliminary Field Study of the Petobo Flow Slide After the 2018 Indonesia Palu Liquefaction

A huge flow slide induced by liquefaction occurred in several areas of Palu city, Indonesia, due to the Mw 7.5 Palu-Donggala earthquake on Friday, 28 Sept 2018. Many villages, including Balaroa, Petobo, Jono Ogee, and South Sibalaya, had experienced catastrophic destructions due to flow slide liquefaction. This study focused on the flow slide area of Petobo. Surface observations and Electrical Resistivity Imaging (ERI) were conducted in the Petobo area. Based on surface observations, the flow slide area can be divided into four possible morphological zones, which include Ground Slide (GS), Lateral Spread (LS), Liquefaction Flow (LF), and Debris Flood (DF). The results of ERI show that in the GS zone near the Gumbasa canal, soil materials are dominated by sandy gravels or gravelly sands. Furthermore, GS and LS zones are covered mainly by dry sand and gravel. Interbedded saturated sands and gravel were found at the top layer of the LF zone. Lastly, the DF zone subsurface is generally composed of silt or clay, interbedded with sand in a saturated condition.

Togani Cahyadi Upomo, Muhsiung Chang, Rini Kusumawardani, Galih Ady Prayitno, Ren-Chung Huang, Muhammad Hamzah Fansuri
Numerical Investigation of the Interacted Behavior of Embankment-Slope System Under Seismic Loading Conditions

In this study, the integrated effects of the geometrical characteristics of slope and the geotechnical strength properties of clayey foundation soils are investigated, considering the relative distance of the embankment from the slope edge under dynamic loading conditions with performing numerical analysis. In this context, a finite-element-based two-dimensional commercial software is used to perform pseudo-static analysis concerning the consideration of the Samos-İzmir earthquake in October 2020. The outcomes of the studies were evaluated in terms of the determining factor of safety values to interpret the effects of the envisaged variants on stability.

Zülal Akbay Arama, Muhammed Selahaddin Akın, İlknur Dalyan, Hazal Berrak Gençdal
Estimating in Situ Deep Soil Dynamic Properties Using PS Suspension Logging and Accelerograph Records. Case from the City of Ica—Peru

In the city of Ica—Peru, there are no data on dynamic soil properties. Therefore, correlations not corresponding to the soil characteristics of this city are currently being used for that purpose. In this study, for determining the dynamic soil properties, accelerograph records and the P-S suspension logging system were used to measure the (P) compressional-wave and (S) shear-wave seismic velocity of deep soil. For this last survey, a 42-m deep well was drilled, and soil with sand and silt was found. In this research, results obtained from the PS suspension records have been compared with the geophysical MASW, MAM, and seismic refraction surveys, the PS-logging being the most accurate technique for determining the velocity of the S and P waves. The values obtained from the shear waves are within the range of 200 m/s to 600 m/s. Likewise, from the accelerograph records, microtremors, and theoretical ellipticity of Rayleigh waves, two predominant periods have been found: T = 0.63 s and T = 3.1 s. Therefore, the shear wave velocity profile has Vs30 = 276 m/s and is classified as type D, according to the ASCE 7–16-2016 standard.

Jorge Alva, Carmen Ortiz, Nicola Tarque, Joseph Montero
Effect of Variabilities in Motion Characteristics and Bedrock Depth on Seismic Ground Response Assessment

The half-space depth significantly affects the seismic ground response by influencing a particular site's amplification and attenuation characteristics. Hence, the present study focuses on assessing the impact of half-space depth on seismic ground response using nonlinear 1-D numerical analysis. The properties of Nevada sand and calibrated nonlinear parameters available in the literature have been used for constructing the numerical models. This study uses a wide range of variations in the motion characteristics, that is, spectral accelerations, frequency contents, and duration characteristics, to assess the seismic ground response for different depths of half-space. An interesting finding of the study is that the effect of bedrock depth on seismic ground response modification differs when assessed at different depths. The response at shallow depth (at 5 m) shows less de-amplification in energy content for large bedrock depth. At the same time, the de-amplification in energy content is almost similar for all the models at 25 m depth. On the contrary, the modification in frequency content is always higher for larger bedrock depth. A regression equation has been proposed to predict the response Arias Intensity (AI) depending on input energy content, half-space depth, and response measurement depth.

Aaditaya Raj Roshan, Angshuman Das, Pradipta Chakrabortty
Non-linear Dynamic Analysis of Structures Including Site Response Effects with Soil–Structure Interaction Problem

This study examines the non-linear dynamic response of reinforced concrete structures under soil site effects in earthquake-induced ground motions. The inelastic analysis procedure is applied to four scenarios involved in comprehensive parametric investigations to determine the seismic performance of the structures. The problem is investigated according to these conditions: a fixed-based condition under bedrock ground motion, a fixed-based condition under surface ground motion, a flexible-based condition under bedrock ground motion, and a flexible-based condition under surface ground motion. The soil–structure interaction (SSI) effect is considered by the substructure method based on impedance function solutions. Moreover, site response analyses for deep alluvial soil profiles are performed using a one-dimensional (1D) wave propagation problem with an equivalent linear approach. The SSI models of the structures are created by using Opensees software. The interactions are represented as displacement and rotation springs, and seismic performances of the structures are investigated in the non-linear time domain. Multi-degree of freedom system building models are converted into the equivalent single degree of freedom systems by the capacity spectrum method. Subsequently, maximum and residual displacements and base shear forces of the structures are investigated comparatively. It is deduced that the local site response effect and soil–foundation–structure interaction should be considered to perform a reliable earthquake-resistant design of buildings and accurately determine the seismic performance of existing structures.

Muhammet Burhan Navdar, Erkan Celebi, Aydin Demir
Assessment of Collapse Potential of Lumped Soil in Alluvial Deposit by Double Consolidation Tests

Alluvial soils transported by water are widely distributed in the arid and semi-arid regions of the world. Due to the increasing population in these regions, quantifying the collapse phenomenon in alluvial soil is essential for safe foundation design. This paper illustrates the assessment of the collapse potential of Ganga basin alluvial sand deposits to quantify the amount of soil settlement. A series of double consolidation tests have been conducted on the different percentages of sand and collapsible lumps mixture to study the variation of collapse behavior. The collapse potential increased linearly with the increase in collapsible lumps percentages in the soil mixture. The collapse potential had been estimated as 19.58%, 17.01%, and 12.22% in the case of alluvial soil containing 90%, 70%, and 30% collapsible lumps, respectively. The collapse potential of the alluvial soil with 100% collapsible lumps is almost doubled compared to soil containing 50% collapsible lumps and 50% sand in the mixture. The results of this study also provided insight into the volume change behavior of the soil mixture in saturated and unsaturated conditions. These experimental results and proposed guidelines will help to improve the design guidelines of foundations resting on collapsible lumped soil deposits in the Ganga basin and similar quaternary alluvial deposits.

Abhik Paul, Pradipta Chakrabortty
Influence of Grain Size Distribution into the Desiccated Crack Behavior of Lateritic Soil

Lateritic soil is rusty-colored soil rich in iron oxide (Fe and Al). Its cracking properties are controlled mainly by the environmental conditions it has been exposed to and the lateritic soil's mineralogical composition. The study area is located at Sungai Merab, Bangi, Selangor, with lateritic soils dominating the landscape. Two samples, (S-O) and (S-F), each with in-situ and fine-grained grain size distribution, were prepared to assess the influence of grain size distribution on the desiccated crack behavior of lateritic soil. The S-O sample contains the original soil composition of the field, whereas the S-F sample is sieved soil that has been passed through a 0.075 mm sieve. The samples were placed in a 24.5 × 17 cm rectangular pan and air-dried in a temperature-controlled room (24.5℃) to achieve desiccation. Four cracking stages can be identified based on the laboratory simulation: namely, the internal drying stage, the surface drying stage, the advanced cracking stage, and the equilibrium stage. The onset of desiccated crack for S-O and S-F samples are on the 9th and 11th days of drying, respectively. Both samples stopped cracking on the 20th and 21st days of drying, respectively. The S-O sample shows higher crack intensity, angularity, and smaller crack segments than the S-F sample. However, the cracking angles for both soil conditions were similar. The desiccated crack behavior of lateritic soils was influenced by the grain size distribution, with finer soils exhibiting a more regularized crack morphological pattern than in-situ soil.

Pavithran Batumalai, Nor Shahidah Mohd Nazer
The Generalized Coefficients of Earth Pressure: Numerical Validation and Comparison with Eurocode 8-5 Method

The first author recently offered a unified continuum mechanics approach for deriving earth pressure coefficients for any soil state between the “at rest” state and the active or passive state, applicable to cohesive-frictional soils and both horizontal and vertical pseudo-static conditions. It is worth noticing that under static conditions, this relatively complicated analysis based on Cauchy's first law of motion, which has been extended suitably to deformable bodies with internal resistance, leads to the well-known Rankine's expression for cohesive-frictional soils for the active state. In the same paper, an analytical expression for calculating the required wall movement for the mobilization of the active (or passive) state is also presented. The validity of the above-mentioned analytical expressions is examined herein through several application examples, comparing the analytical results with the respective finite element analysis results. The comparison showed that the proposed expressions are excellent tools for calculating earth pressures and displacements. The results were also compared against the respective ones obtained using EN 1998-5:2004 and the prEN 1998-5 (2021 draft standard). The comparison shows that both Eurocode 8-5 versions’ return values that significantly deviate from the respective finite element analysis.

Lysandros Pantelidis, Panagiotis Christodoulou, Eleyas Assefa, Costas Sachpazis
Evaluation of the Influence of Olive Pomace Addition on the Geotechnical Properties of Clay Soil

In Algeria, olive cultivation is booming. Most of it is destined for oil production, while the extraction of oil in Algerian oil mills generates large quantities of by-products known as olive pomace. Within the framework of the valorization of agricultural waste in soil stabilization and to reduce the costs of stabilization operations, road construction, and to protect the environment, an experimental study on the effect of olive pomace on plastic soil or, in other words, “problem soil” has been carried out. This study aims to determine the engineering and geotechnical properties of poor soil improved by using olive pomace with different percentages (0, 2, 4, 6, and 8%) carried out on different physical and mechanical tests. Through this experimental study, we observed that with the increase in the percentage of olive pomace, the plasticity index of the treated soils decreases, and the shear resistance properties increase. On the other hand, the highest shear strength properties of the treated soil were obtained for the additions of 4 and 6% of olive pomace. Overall, it can be concluded that olive pomace can be considered an ecological and economical solution for treating clay soils in developing regions.

Inas Berdi, Dounia-Mey Rebiai, Riad Benzaid, Salah Messast, Imen Idoui
Mechanical Properties of Nano-Silica-Treated Organic Soil Reinforced with Banana Fiber

Nano-additives have proven the effects in geotechnical engineering through their application as soil-stabilizing material. The most abundant and commonly used nano-material is nano-silica. However, the literature shows that soil treated with nano-silica is brittle, which would cause sudden and catastrophic failure. On the other hand, fiber-treated soil showed better post-peak failure response than treated soil. Hence, the present work focuses on the performance of organic silt treated with banana fibers and nano-silica (of size 17 nm) through unconfined compression tests and permeability tests. The soil is treated with four different dosages of banana fibers, namely 0.25, 0.50, 0.75, and 1.00% by dry weight of the soil. The average aspect ratio of the banana fibers used is 10. Therefore, the optimum dosage of fiber is found to be 0.75%. Strength increases by nearly 17% with the addition of 0.75% banana fiber. Further, the soil has been treated with 0.75% of banana fiber and four different dosages of nano-silica ranging from 0.2 to 0.8% by dry weight of soil. Results of unconfined compression tests indicate that soil treated with 0.75% fiber and 0.4% nano-silica effectively improved soil strength. Also, the post-failure response was gradual rather than a brittle failure, as experienced in nano-silica-treated soil. The strength was enhanced by nearly 57% for the optimum dosage of fiber and nano-silica. The results of permeability tests showed a marginal rise in magnitude owing to the introduction of banana fiber and aggregation reaction of soil caused by nano-silica. This indicates that the soil medium tends to be well drained by adding fibers and nano-silica. Surface morphology analyzed through micrographs of scanning electron microscope shows that nano-silica created better aggregation in soil particles. The fibers acted as a bond in the aggregated soil mass. Hence, nano-silica helped enhance the soil strength, and banana fibers served as an aid to avert brittle failure in improved soil.

Govindarajan Kannan, Evangelin Ramani Sujatha
The Karal Soil from North Cameroon: A Swelling Soil Stabilized with a Mixed Cement/Hydrated Lime Treatment

The swelling clay-rich soils, known as karal soils in Cameroon, cover a large area in the North of the country. Such soils used in earthwork for road construction are at the origin of damages to structures whose durability is drastically shortened. Based on the usual soil treatment for road construction, the present study demonstrated the ability of a mixed treatment with a hydraulic binder (CEMII) and hydrated lime (HL) to decrease the swelling phenomenon and improve the mechanical performance of karal soils. Hydrated lime was imposed by the near non-existence of quick lime (QL) in Cameroon. It made the originality of the applied treatment that usually rarely combines CEMII and HL. To test the durability of the formulated soil treatments with various additives contents, long or short cycles of wetting-drying was imposed, and the volume variation until the total disaggregation of soils was followed. Tests confirmed the possible use of a CEMII/HL mixture to prevent soil from damages caused by the swelling-shrinkage phenomenon.

Lemankreo Bakaiyang, Myriam Duc, Yasmina Boussafir, Fabien Szymkiewicz, Jérémie Madjadoumbaye
Mixing Nanoclay Additive to Improve Internal Erosion Resistance of Earth Dams Constructed of Silty Sand

Seepage-induced erosion is one of the main reasons leading to the catastrophic failure of earth dams, levees, and dykes. Mitigation measures include grouting or mixing additives with the soil. In the present study, nanoclay (NC) was investigated as an additive for silty sand soil, considering 1 and 1.5 wt.% NC additions, employing curing periods of 1, 7, 14, and 28-days for the soil–NC mixtures. Homogeneous model dams were then prepared by compaction of the unamended and cured -amended soil materials to the same cross-sectional profile in a laboratory flume apparatus. Once the upstream water level had reached the required water depth, the internal erosion process was initiated by opening a 6-mm dia. preformed hole created through the base width of the model dams next to the flume’s glass sidewall panel. To track the entire erosion process, side-view video recordings of the eroding dam cross-section were taken, employing a novel digital image-processing technique (previously developed by the authors) to track the progression of piping that ultimately lead to breach failure occurring. Original experimental results presented herein show the positive effect of the NC addition on erodibility reduction. From the NC content and curing ranges examined, the 1 wt.% NC and minimum 7-day curing period combination were tentatively identified as producing the best improvement in internal erosion resistance for the investigated soil.

S. M. A. Zomorodian, M. J. Ataee Noghab, M. Zolghadr, B. C. O’Kelly
ANNs-Based Prediction Models for Consistency and Compaction Characteristics of Bentonite–Sand Mixtures

This study is fictionalized with the use of ANNs logic to estimate the compaction parameters of bentonite–sand mixtures. Totally 230 sets of tests were digitized from the nine well-accepted literature sources to specify the grain size, consistency, and compaction parameters of the bentonite–sand mixtures. Matlab R2018a software is used to perform the estimation process of the compaction parameters, and representative expressions were derived to ease the determination process of mixtures. Consequently, the applicability of the suggested expressions has been checked by the determination and comparison of well-known international metric measurements.

Melda Yücel, Zülal Akbay Arama, Hazal Berrak Gençdal, Begüm Başbuğ, Edip Seçkin
Use of Heuristic Regression Techniques in Stability Control of Cantilever Retaining Walls

This study investigates the stability conditions of cantilever retaining walls via heuristic regression techniques. The well-known heuristic regression techniques have been preferred to gain results quickly. In this study, heuristic regression techniques, including the M5 model tree and the Multivariate Adaptive Regression Splines, have been employed to investigate the model that provides sliding, overturning, and bearing capacity safety factors. Root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R2) have been utilized in the comparison of estimation for safety factors from the numerical analyses of 1024 different cantilever retaining wall designs. Reasonable values of RMSE, MAE, and R2 for models of safety factors have been obtained as 0.046, 0.008, 0.462 for sliding, 0.036, 0.007, 0.275 for overturning, and 0.999, 0.999, 0.998 for bearing capacity, respectively. This result demonstrates that an improved model by heuristic regression techniques for the cantilever retaining wall’s stability check can be employed reliably and effectively.

Vahdettin Demir, Esra Uray
Effect of WTP Lime Sludge on the Properties of Agricultural Soil of Jumar Watershed, Jharkhand, India

The case study of Jumar Watershed, Jharkhand, India, has been considered for experimental study. This experimental research aims to evaluate the change in selected Index and physiochemical properties of agricultural soil by using water treatment plant lime sludge to improve the productivity of the soil. The watershed is known to have a frequent termite infestation, which destroys farmland productivity. Soil samples were collected randomly using GPS from farm plots at 5–30 cm depth. Lime sludge was collected from the Rukka water filtration plant, Rukka, Ranchi, Jharkhand. Lime sludge was applied as 3 and 6%, by weight of soil. Then the soil index properties (water content, density, specific gravity, Atterberg limits) and soil physicochemical properties (pH, bulk density, electrical conductivity) were calculated for each added percentage. The study revealed that using lime sludge can increase the water holding capacity of soil by increasing pore space and acting as a good soil conditioner.

Soumya Pandey, Neeta Kumari
The Debris Flow Along Brungkah River, Pacitan, Indonesia, Caused by the Rainfall Incident of November 27, 2017

On November 27, 2017, a debris flow occurred in the Brungkah river, Pacitan, Indonesia, caused by extreme rainfall. Debris flow passed through and transported the sediment materials along the Brungkah river and stopped at the river confluence with the Grindulu river. The debris flow destroyed the main village access road to the Tukul dam and clogged the Grindulu river, the deposition area. Mapping on the ground surface and topographic cross sections along the Brungkah river area has been conducted to determine the source and volume of debris materials and the impact of debris flow. Results show the source of debris materials came from a previous wedge-shaped landslide with an area of approximately 2.6 ha, located upstream of the Brungkah river. The recurrence of landslides along the river has not been recorded well throughout history. The debris flow transported materials of sands and silts and various sizes of rocks by gravity flow to the deposition area. Using topographic cross sections, the volume of debris materials is estimated to be 78,000 m3.

Togani Cahyadi Upomo, Muhsiung Chang, Rini Kusumawardani, Galih Ady Prayitno, Sari Meliana, Muhammad Hamzah Fansuri
An Intelligent Model to Predict the Compactness of Granular Mixtures Used in Conventional (CC) and Roller-Compacted Concrete (RCC)

The granular compactness is the first-order geotechnical parameter. Its optimization is very important from a technical and economic perspective. It depends on several geometrical and physical parameters. It is experimentally measured or predicted using theoretical models that are not always applicable for particular granular mixtures such as roller-compacted concrete (RCC), which contain large diameter aggregates and fillers. This work aims to develop an artificial intelligence model to predict the compactness of granular mixtures used in conventional and roller-compacted concrete. The modeling is carried out through a database resulting from an experimental study conducted in the lab on 140 granular mixtures. The compactness of these mixtures was measured by an experimental system designed and optimized in the lab. Thus, three artificial neural network (ANN) models were developed to predict the compactness as a function of some basic geometrical parameters (Dmax, intermediate diameters Di, curvature Hazen’s coefficients, and the percentage of fillers). After validation, the global prediction model of the compactness showed a good performance with a good correlation (R > 0.91 and low root mean squared error).

Ahmed Hadj Sadok, Youcef Chakali, Mahfoud Tahlaiti, Mohamed Mohamed Ali
Choosing an Effective Design Solution for Fixing Offshore Hydro-Technical Structures to Shelf Ground

Pile foundations usually fasten hydro-technical oil–gas mining facilities to seabed soils in Caspian Sea aquatoriums. Sustainability of strength and stability during the design and construction of hydraulic structures requires solving several theoretical and practical problems. Numerous static and dynamic tests (experiments) were carried out in the Caspian Sea aquatorium and in laboratory conditions to solve these issues. The widespread use of pile foundations in developing offshore oil and gas fields revealed the inconsistency of the domestic scientific methodological and regulatory framework for calculating their load-bearing capacity over the soil. It is established that the wave strikes, acting on pile foundations, interact with the surface design of offshore structures and offshore ground bases. Sea wave banging pile foundations creates vibrations in the pile foundation—topsides offshore structures and moving piles in the subgrade. Displacement piles depend on the reaction strength between the structure subgrade and the intensity of the shock wave in the time that passes through piles for offshore soil. At the same time takes into account the rheological properties of composite models of shelf soil.

Latif F. Aslanov, Firidun L. Aslanov
Latent Hydraulic Effect of Ground Granulated Blast Furnace Slag on the Strength Development of Stabilized Peat

Peat is identified as soft organic soil with high water retention. It cannot be stabilized with Portland cement for soil improvement due to its impediment to cement hydrolysis. Hence, there is a need to explore suitable additives for effective peat stabilization. This study sampled tropical peat from Sri Nadi village in Malaysia before being transported to the laboratory for testing. Ground granulated blast furnace slag (GGBS) and Portland composite cement (PCC) were investigated as peat additives for stabilization purposes. The PCC had 4% calcium chloride and 2% polycarboxylate superplasticizer by weight of the cement. Calcium chloride and polycarboxylate superplasticizer acted as cement accelerators and workability-enhancing agents for stabilizing the peat. The latent hydraulic effect of GGBS was evaluated by varying its content from 0 to 15% of PCC in the mix designs of stabilized peat specimens. After curing, each test specimen was crushed until failure in an unconfined compression test. It was discovered that a mix design of 300 kg m−3 binder dosage (90% PCC: 10% GGBS) and 596 kg m−3 river sand dosage is optimal for stabilizing the soil. The test specimen’s 90 days unconfined compressive strength and elastic modulus were 573 and 11,750 kPa, respectively. The unconfined compressive strength was higher than the minimum strength value of 345 kPa required for effective soil stabilization. The key findings are enormously impactful on the mass stabilization of peat at construction sites.

Leong Sing Wong, Hasan Omar Ali Alhaddad, Raed Saleh Ali Ba Bakri, Hattan Ahmed Ahmed Haider, Ahmed Farid Mahmoud Oweida
Machine Learning Approach for Exploration: A Case Study in the Central Sumatra Basin, Indonesia

Geologically, the Central Sumatra Basin represents a series of present-day back-arc basins that are present along the central region of Sumatra island. At the same time, Central Sumatra Basin is the biggest oil producer basin in Indonesia with large subsurface data sets. These large data sets need to be re-evaluated to optimize the exploration strategy. These studies demonstrate the effectiveness of machine learning methodologies in constructing a detailed model of facies and hydrocarbon distribution. This has been made possible using many fascinating algorithms especially supervised learning, such as K-Neighbors Classifier, AdaBoost Classifier, Random Forest Classifier, and other algorithms. The modeling process uses static and dynamic petro-technical data, including petrophysical, geological, geophysical, production, and reservoir data sets, which the existing contractor already interprets. The algorithm was trained and tested to data sets and then analyzed which feature was suitable for each machine learning method. The facies and hydrocarbon distribution results can help understand and identify the regions that are more likely to have oil and gas-producing rocks. In addition, it shows the importance of good data cleansing and labeling to get a better machine learning model. These machine learning results can be used in exploration strategies and get a valuable model to decide which prospect to be drilled.

Zain M. Rubianto, Yudha R. Sinulingga, Mohammad K. Utama, Shinta Damayanti, Andrean Satria, Diponegoro Ariwibowo, Khairul Ummah
Comparison of Micromechanical Elasticity Models for Cemented Soils

Cemented soils have particles held together by a binding agent. Of particular interest are weakly cemented soils found in an intermediate state, between granular and solid, when loading begins to break their bonds. To properly understand and describe such materials, appropriate contact laws are needed. This constitutive behavior has two main parts, elasticity and bond rupture; several works have focused on the bonds’ failure criterion, and fewer have dealt with their elastic response. This work compares granular specimens’ macroscopic elastic behavior based on various contact bond laws employed with the discrete element method (DEM). An advanced bond law proposed and evaluated by one of the authors is compared with the other two simpler laws in formulation but well established in the literature. Cementation is applied to DEM samples with spherical grains in different isotropic states with different densities and contact connectivities. Overall, all laws can capture some fundamental aspects of the samples’ elasticity and its dependence on the bond characteristics (bond geometry, bond stiffness). However, as the bond law becomes more complex, more effects affect the macroscopic elastic response.

Alexandros I. Theocharis, Achilleas G. Papadimitriou
Characterization of Soils for Road Works: Case Study of Borrow Pits in Kwara State, Nigeria

Soil is the ultimate material for road construction and to ensure its suitability for construction. Therefore, its properties must be evaluated. Therefore, there is a need to determine the strength and evaluate the stiffness property of the soils for design and construction purposes. This study aimed to assess the strength and stiffness properties of lateritic soils within Ilorin that can be used for static and dynamic analysis of traffic loadings on roads/pavement structures. A laboratory test was conducted on soil samples collected from two identified borrow pits within Ilorin per BS 1377, and resilient modulus was estimated from California bearing ratio (CBR) value. From the preliminary investigation carried out on the soil samples, the soil samples at Oko-olowo pit are a silt clay with A-7-5 AASHTO classification. In contrast, the samples from Tanke pit are clay with A-7-6 AASHTO classification. The CBR and resilient modulus determined for the samples from the pits are 44.65% and 200.16 MPa and 56.40% and 233.50 MPa, respectively, indicating that the materials have road subbase characteristics that can be improved upon as base material. Therefore, the study recommends detailed soil investigation before the design and during construction of a road to ascertain the quality of the material employed.

Oluwafemi Daniel Oguntayo, Lukman Kolade Olufawoye, Olumide Moses Ogundipe, Oluwasegun Aladegboye, Temitope Funmilayo Awolusi, Oladapo Praise Ejigboye, Bernard Yinka Oguntayo
Observations of the Landslide Mitigation of Rock Slopes on the Pilgrimage Route Between Makkah and Mena in Saudi Arabia

The pilgrimage route between Makkah and Mena in Saudi Arabia is heavily used during the pilgrimage season. Just within three days, millions of pilgrims take this route. The route lies in high rock and steep mountains with moderate to high landslide risk. The rock slopes were cut to enable road construction, increasing the risk of landslides. Therefore, a wide range of slope stability measures were applied to ensure the safety of people using the route and to reduce landslide risks. Barriers such as gabions and concrete beams were constructed on the slope surfaces. Rock netting, nailing, and shotcrete were also applied to protect the rock slopes. However, the slope stability measures are insufficient in several locations to minimize the risk. Therefore, a risk remains, which has to be considered further. This paper presents observations on the implemented slope stability measures and discusses their shortcoming. In addition, a qualitative hazard assessment was also conducted, and recommendations for further remediation were suggested.

Abdullah Kallash, Hernan Vigil Fernandez
Estimation of Strength Properties of Evaporitic Rocks from Their Quick-Measurable Physical Properties: A Case Study, Abu Dhabi City, United Arab Emirates

Estimation of rock strength like uniaxial compressive strength (UCS), indirect tensile strength (ITS), and point load index (PLI) is important responsibilities in various engineering applications. Rock masses are anisotropic, and the number of rock features highly influences rocks’ strength. Abu Dhabi, the capital of the United Arab Emirates (UAE), is sited upon evaporites and carbonate rocks that dominate the bedrock beneath the city. The evaporites have variable textures and structures strongly affected by the anthropogenic urbanization conditions, which lead to changes in the strength properties. In this study, to estimate the strength of evaporitic rock such as UCS, ITS, and PLI (Is(50)), a large number of UCS (257 samples), ITS (327 samples), and PLI (Is(50)) (357 samples) from 27 sampling locations were tested, and γn (natural unit weight) (989 samples), γs (saturated unit weight) (355 samples), and Gs (specific gravity) (989 samples), were measured. The linear and non-linear regression analyses were performed between the mean UCS–γs, ITS–γn, and PLI (Is(50))–Gs. The representative best-fit lines equations and the corresponding correlation coefficient, R values, were estimated. The relations between the mean UCS–γs, ITS–γn, and PLI (Is(50))–Gs are approximated with exponential and linear equations, and R values are 0.73, 0.57, and 0.62, respectively. Finally, this study proves that the strength properties can be estimated from their quick-measurable physical properties. Such findings can help engineers and decision-makers mitigate problems, especially during the preliminary design stage.

Hasan Arman, Mahmoud Abu Saima, Osman Abdelghany, Ala Aldahan, Safwan Paramban
Porosity and Water Content Prediction with Dry Unit Weight Measurements of Evaporitic Rocks from Abu Dhabi City, United Arab Emirates

The evaporitic rocks commonly occur at the surface or depth and may be found in the foundations of buildings and infrastructure constructions in Abu Dhabi. The evaporites typically are composed of gypsum, anhydrite, and halite-rich sediments. Due to their variable textures, structures, and chemical composition, and changes in the surrounding conditions because of watering and dewatering, their mechanical and physical properties can variate. Therefore, predicting the porosity (n) and water content (WC) of evaporites is critical at various stages of construction. The aim is to simply predict the n and wc of evaporites from their measured dry unit weights (γd) and provide guidelines to engineers to help reduce the cost of hazards assessment of the engineering projects constructed on/in evaporite rocks. Extensive field study and rock sampling were carried out, and evaporite rock samples were collected from 27 locations in Abu Dhabi city and its surroundings. The n, wc, and γd of evaporitic rocks were measured on 355 samples. The linear regression analyses indicated that the mean n and wc decreased with the mean γd of evaporitic rocks. The representative best-fit lines equations and the corresponding correlation coefficient, R values, were estimated as −0.85 and −0.78. Fast, simple, and reliable prediction of n and wc from γd will be useful and initiate the possibility of quick judgment/prediction of evaporite durability and strength behavior. Ultimately, the study will benefit the UAE economy, help minimize risks, and increase engineering structures’ safety.

Hasan Arman, Mahmoud Abu Saima, Osman Abdelghany, Ala Aldahan, Safwan Paramban
Kinematic Stability Evaluation of the Cut Slopes Along Islamabad–Muzaffarabad Dual Carriageway (IMDC), Pakistan

This research kinematically evaluates selective rock cut slopes, comprised of alternate beds of sandstone, mudstone, siltstone, claystone, and shale, along the Islamabad–Muzaffarabad Dual Carriageway (IMDC), Pakistan. Thirteen instability-prone sites were selected, and discontinuity-orientation data were collected using the window mapping method. The representative geological cross sections for all slopes were prepared, and pronounced failure modes were recorded. Fresh rock samples were collected to evaluate the potential for the disintegration of the various rock units by determining the slake durability index. In interlayered rock units, the higher weathering rate of lower incompetent units removes the support and triggers the gravitational falling of the competent rock blocks. Despite dipping into the slope—a most favorable condition—due to differential weathering, one of three prominent joints dips toward the slope resulting in plane or wedge failures that ultimately fall as rock blocks. In the present study, a kinematic criterion is proposed for predicting undercutting-induced instabilities that are not identified by conventional kinematic analyses. The results showed that the undercutting is more pronounced along gentler bedding joints either into or out of the slope; on the other hand, it has less effect on the slope where the strike is across the slope, dipping on either side at steep to very steep angles.

Luqman Ahmed, Mian Sohail Akram
Novel Damage Quantification Techniques for Thermal-Treated Granitic Rocks

Analyzing the response of thermally treated granitic rocks is crucial for enhanced geothermal systems (EGS), nuclear waste disposal in deep geological repositories (DGR), and fires in monuments. However, the nature of thermal interaction differs significantly among these processes due to considerable variation in the type of heating source, its energy output, and other geotechnical considerations. In this study, the response of several granitic rocks subjected to heat treatment with rapid cooling was analyzed to quantify the damage using established and novel models. Damage quantification is critical since it appraises the nature of alteration at high temperatures and aids decision-making under vital circumstances such as monument fire. Simultaneous mineralogical and morphological changes within the rock matrix alter the physicomechanical and failure response. Novel damage models based on these properties were developed, analyzed, and compared with the established modulus-based model. While models based on porosity, strengths, and wave velocity render similar results, density and strain-based models do not predict similar damage magnitudes. However, the trend of damage is similar to a modulus-based model. This can be attributed to the degree of susceptibility of a property to high temperature. Since rocks like granite undergo brittle–ductile transformation at high temperatures, various strength-based brittleness indices were calculated and correlated to damage. The damage models and brittleness-based correlations indicate a critical temperature at 400 °C beyond which substantial damage and change in nature of the failure are observed within granites.

Rahul Katre, Nikhil Sirdesai
Behavior of Cracked Grout Bodies of Micro-Piles with Different Corrosion Protection Measures

Tensile elements are used for various geotechnical tasks to transfer loads into the subsoil. With the requirements regarding load-bearing capacity (ULS) and serviceability (SLS), additional issues, such as their durability, must be considered in the design. Due to subsoil properties and groundwater, insufficient corrosion protection can lead to massive corrosion damage of tensile elements. In addition to the effects on service life, such damage can also influence the serviceability and, subsequently, the load-bearing capacity. Therefore, different corrosion protection systems depend on subsoil conditions, the planned service life, and external influences. This paper presents investigations dealing with the issue of corrosion due to cracking of the grout body of micro-piles. In two tests, samples with different corrosion protection measures were subjected to tensile stresses. In addition to a visual recording of the crack patterns, computer tomographic scans were carried out. Therefore, in addition to verifying the crack formation, these investigations allowed us to evaluate the “interior” of the grout body. Thus, the studies provide information on the function of different corrosion protection measures.

Matthias J. Rebhan, Cornelius Dold, Franz Tschuchnigg, Stefan L. Burtscher, Roman Marte
A Fatigue Damage Propagation Model Based on Locally Periodic Micro-crack Growth

This paper develops a new micro-mechanical damage model for fatigue crack propagation in tensile (Mode I) cyclic loading. The double-scale fatigue damage model is entirely obtained through small-scale yielding descriptions of micro-crack propagation. Based on the Paris fatigue crack growth law, the stress intensity factor range is expressed thanks to an appropriate micro-mechanical energy release rate analysis coupled with asymptotic homogenization developments. The macroscopic fatigue crack evolution law is established. Numerical simulations are presented. The reliability of the model to reproduce stress-strain shielding is demonstrated. The influence of the microstructural length on fatigue damage evolution is illustrated. The numerical results are compared with fatigue crack propagation tests performed on Ti-6Al-4V titanium fashioned by additive layer manufacturing (ALM). Through the calibration process, the model agrees with the experimental results.

Oumar Keita, Vincent Velay, Remi Lacoste, Farhad Rezai-Aria

Geo-informatics, Remote Sensing and Geohazards

Frontmatter
Tree Detection from Very High Spatial Resolution RGB Satellite Imagery Using Deep Learning

Tree detection from space imagery is important in the agriculture and forestry industries. However, very high spatial resolution satellite imagery represents fine details on the ground making the object detection task more challenging. Most of the existing tree detection methods use multispectral bands, including an infrared (IR) band, which provides distinct information about vegetation areas making the detection task more manageable. However, the sheer amount of optical data employed as input to information extraction procedures contains only three bands, and IR bands may not always be available. Thus, this study presents automatic tree detection by only using the Red, Green, and Blue (RGB) bands of very high spatial resolution satellite images through deep learning. The proposed method was built on top of a U-Net architecture whose ability to detect different types of trees is explored. The U-Net architecture was trained using WorldView-3 RGB images. In addition to RGB bands, vegetation indices were computed and used as additional bands to investigate their effects on the results. In this respect, six models were generated, and each model was trained and tested individually. The models used include (RGB, RGB + VARI, RGB + GLI, RGB + GRVI, RGB + all indices, and only vegetation indices). Four accuracy assessment equations were calculated for each model, and the results were compared.

Abdullah Sukkar, Mustafa Turker
Integrating LiDAR and Landsat Images for 3D Visualization

In this work, we present a visualization tool of 3D spaces obtained from integrating Landsat and LiDAR images. The increasing necessity of visualization tools in geosciences and the availability of information motivated this project. The tool was developed using the Unity 3D engine, which is widely used in the video gaming industry. In this work, we combine images from different sources, such as Landsat 7, Landsat 8, and Sentinel 2, with a digital elevation model obtained from LiDAR images, producing a virtual reality environment. Furthermore, we applied some remote sensing techniques, such as spectral enhancement, false color composites, and band ratios to identify some specific features of the area of interest. The visualization can be done using a virtual reality visor, such as Oculus Rift or Google Cardboard, but you can also view the results on a single smartphone. This tool can bring us new opportunities to explore the earth, breaking at some point the spatial barrier and being able to study remotely almost any place of interest. The tool is focused mainly on geophysics and geology students at the National Autonomous University of Mexico as an alternative for field courses. Still, it can be widely used in any other area.

Nizar K. Uribe-Orhiuela, Fernando Brambila-Paz, Ivette Caldelas, Rodrigo Montúfar-Chaveznava
Comparison of Multiple Machine Learning Methods for Estimating Digital Elevation Points

Numerous engineering applications need topographic surfaces, and topography should be adequately determined. This study evaluates the estimation accuracy of three different machine learning methods in digital elevation model (DEM). Accurate DEM estimation is vital in water resources engineering, management, and planning. In this study, elevation values (Z) of the Mert River Basin of Samsun were estimated by deep learning (DL), gaussian process regression (GPR), and support vector machine regression (SVMR) from multiple machine learning methods. Estimates were tried with X and Y coordinate information as the input scenario. In addition, root mean square error (RMSE), mean absolute error (MAE), nash–sutcliffe efficiency (NSE), and coefficient of determination (R2) were utilized as comparison criteria. When the results were examined, it was determined that the best estimation method was GPR (R2 = 0.997), then SVMR (R2 = 0.975), and the worst modelling was DL (R2 = 0.972). This result shows that an improved model by machine learning methods can be used in the DEM modelling.

Vahdettin Demir, Hatice Çıtakoğlu
Improvement of the PeruSAT-1 Satellite Image Orthorectification Using the Optimization Algorithm

The rational polynomial coefficients (RPCs) are constants available in the metadata of satellite images and are used for orthorectification. However, the accuracy of an orthorectified image can be improved by modifying the original RPCs through an optimization algorithm (OA) based on the cost function (CF) and gradient descent method (GD). The OA is applied to the rational function model (RFM) to modify the original RPCs to obtain new RPCs and improve image orthorectification. The analysis of results showed that the difference between the coordinates performed by differential GPS and the initial coordinates obtained from the original RPCs has an average error of 19.45 m. In comparison, the coordinates obtained from the modified RPCs have an error of around 2.25 m. Therefore, this methodology reduces error by 11.6% and improves orthorectification. Applying this new proposed methodology will allow us to improve the geometric accuracy of the satellite images and reduce the errors generated by the original RPCs.

Rodolfo Moreno, José Eche, Clinton Samaniego, Antonio Quispe
Fortune’s Algorithm for Calculating the Voronoi Diagram of Polylines, Polygons, and Functions

The Voronoi diagram is part of the field of computational geometry, just like the Delaunay triangulation, the convex hull, the bounding rectangle, etc. It is used in many areas, including mathematical morphology, cartography, and volume reconstruction. The Voronoi diagram divides the space between several sites, thus forming Voronoi cells. Sites can be points, segments, objects, etc. Several algorithms allow the calculation of the Voronoi diagram. Among these algorithms, there is the Steven Fortune algorithm. We will see in this paper the application of the algorithm on polylines, polygons, and mathematical functions, we study the Voronoi cell shapes for the different objects, and we have highlighted the particular cases. In this work, the algorithm is implemented in Lazarus (based on the Pascal language), and we were able to test it on datasets of different types and geographical maps. We compared the results with another algorithm (Voropix), and the results were the same.

Nardjes Hamini, Mohamed Bachir Yagoubi
Ecological Shifting and Land Use Land Cover Changes in Pindari Valley, Uttarakhand Himalaya, India

The current study assessed the spatial and temporal ecological dynamics shift of land use and land cover of Pindar valley in Uttarakhand Himalaya, India, for five decades from 1972 to 2018 (46 years). The area is classified using supervised and unsupervised classification, maximum likelihood, and K-means techniques. Seven major LULC categories were identified: agriculture, forest, grassland, scrubland, settlement, snow, and water. Results indicate that since 1972, settlement, agriculture, grassland, scrubland, and water body have increased by 0.1% (0.07 km2), 0.31% (0.23 km2), 4.55% (17.84 km2), 0.8% (2.41 km2), and 1.47% (5.73 km2) respectively, while forest and snow cover has decreased by − 6.32% (− 24.74 km2) and − 2.79% (− 2.26 km2), respectively. In addition, water bodies increased due to the rapid melting of glaciers. It is a maiden attempt to study the upper Himalayas, a part of the Pindar Valley region, for change detection of an ecological shift in land use and land cover.

Arvind Pandey, Deepanshu Parashar, Jiwan Singh Rawat, Bidyutjyoti Baruah, Ajit Pratap Singh, Sarita Palni, Kalpana Gururani, Arti Jyala, Pankaj Kumar Bhatt
The Challenge of Spectrally Separating Seagrass and Macroalgae Species Using Hyperspectral Data

Differentiating seagrass and macroalgae species using remote sensing is very challenging, mainly due to limitations in spectral resolution to distinguish their reflectance spectra. Therefore, it is necessary to determine the optimal wavelength to separate seagrass from macroalgae species. This research aims to determine the most feasible approach to map seagrass and macroalgae species based on hyperspectral data. We measured the reflectance spectra of ten seagrass species in Indonesia, including seagrass covered by epiphyte and six macroalgae species frequently encountered within seagrass meadows. The reflectance spectra for each species were measured at different parts of the object. Continuum removal analysis was conducted to identify the location of the absorption features, and first-derivative analysis was performed to determine the wavelength ranges needed to differentiate these species. The results of this study indicated that it is challenging to differentiate species that contain similar dominant pigments. However, the reflectance spectra and absorption feature locations of all seagrass and green macroalgae species are very similar. Moreover, the reflectance spectra and absorption feature locations of seagrass covered by epiphyte are similar to brown macroalgae species. On the other hand, red macroalgae have a unique reflection response with five reflectance peaks. Our findings indicated that the effective differentiation of seagrass and macroalgae through hyperspectral remote sensing is not based on species variation but on differences in the dominant pigments contained in each species.

Pramaditya Wicaksono, Amanda Maishella, Setiawan Djody Harahap, Ignatius Salivian Wisnu Kumara, Muhammad Afif Fauzan
Accuracy Assessment of Pan-Sharpened PRISMA Hyperspectral Image for Seagrass Species Composition Mapping

Seagrass species mapping is challenging due to the high similarity of reflectance spectra among healthy seagrass species. In Indonesia, a single seagrass meadow is commonly occupied by different seagrass species, which adds to the complexity of seagrass species mapping. The availability of a newly introduced PRISMA hyperspectral sensor (30 m) with an additional panchromatic band (5 m) has opened a new possibility for effective and efficient seagrass species mapping in comparison with airborne hyperspectral imaging. Therefore, assessing the accuracy of pan-sharpened PRISMA hyperspectral seagrass species composition mapping in optically shallow tropical water is necessary. Karimunjawa Islands, Indonesia, was selected as our study area. The PRISMA hyperspectral image was obtained at level 2C, at-surface reflectance geocoded level. Smoothing filter-based intensity modulation (SFIM) pan-sharpening algorithm was used to pan-sharpen the 30 m hyperspectral bands into 5 m spatial resolution. LSMA was conducted to obtain the composition of seagrass species and other benthic covers from the pan-sharpened PRISMA hyperspectral image pixels based on the pure endmembers of six tropical seagrass species, bare substrates, and macroalgae. Field seagrass species data for the accuracy assessment reference was collected using photoquadrat and phototransect techniques. Our results indicated that using LSMA for seagrass species mapping using a pan-sharpened PRISMA hyperspectral image is ineffective. They produced low accuracy due to the similarity of spectral response between seagrass species.

Amanda Maishella, Pramaditya Wicaksono
Relative Water Column Correction Methods for Benthic Habitat Mapping in Optically Shallow Coastal Water

Relative water column correction (WCC) is a method to minimize the effect of water column energy attenuation on remote sensing images that requires fewer inputs compared to more robust absolute WCC methods, hence the broad applicability. Lyzenga developed the frequently used relative WCC method Lyzenga (Applied Optics 17:379–383, 1978) called the “water depth invariant bottom index” (DII). This method is known for its simplicity and accuracy. However, this method does have several limitations; hence, several relative WCC methods have been developed to improve it, among others, by Conger et al. (IEEE Transactions on Geoscience and Remote Sensing 4: 1655-1660, 2006) and Sagawa et al. (International Journal of Remote Sensing 31: 3051-3064, 2010). This research compared the accuracy of benthic habitat mapping based on applying the aforementioned relative WCC methods on WorldView-2 images to recommend the most effective and efficient relative WCC method for mapping the benthic habitat in a complex underwater topography environment. Random forest classification was used to classify water column corrected pixels into different benthic habitat classes. Confusion matrix analysis was used to assess the accuracy of classification results. This research showed that the improved relative WCC methods increased the mapping accuracy. The accuracy differences between these relative WCC methods are within 3.03%. Therefore, these relative WCC methods are applicable to high-transparency optically shallow water areas and complex underwater topography, such as Kemujan Island. Nevertheless, depending on the specific mapping objectives, it is recommended to use the improved relative WCC methods if the necessary inputs are available.

Setiawan Djody Harahap, Pramaditya Wicaksono
Evaluation of WaPOR Evapotranspiration Product for Irrigated Orchards in an Arid Region

With the scarcity of water resources and climatic variability aggravated by climate change, the Mediterranean region's agricultural sector faces serious water allocation challenges. In the central region of Tunisia, characterized by an arid climate, the arboriculture sector is moving forward with the intensification of groundwater resources’ exploitation. Hence, accurate water management becomes a crucial need. Currently, remote sensing products, such as the FAO’s portal to monitor Water Productivity (WAPOR), offer the possibility to assess water consumption in near real-time and for a large area. In this work, the accuracy of WAPOR's evapotranspiration product is evaluated on irrigated arboriculture areas based on comparison with the water balance and FAO-56 methods deployed using in situ measurements. During 2021, six orchards of almond, pistachio, and olive trees in full production were surveyed. Two weather stations in the region measure the rainfall and the meteorological variables needed to calculate the reference evapotranspiration (ET0) with the daily time step FAO-56 Penman–Monteith. The crop cover’s phenological stages are surveyed weekly, and each species’ crop coefficient is adjusted to local conditions. On the other hand, from the WAPOR database, we used the 10-day ETa available at 100 m (ETaWaPOR). Based on the FAO-56 method, the actual evapotranspiration (ETaFAO56) is calculated using the adjusted single crop coefficients and then used to validate ETaWaPOR. Despite that WaPOR is assumed to overestimate ETa of irrigated fields, the comparison with in situ values shows an underestimation for the three studied crops and mainly for pistachio and almond, for which ETaFAO56 is seven times higher than ETaWaPOR. Due to the high divergence between the two estimated ETaFAO56 and ETaWaPOR, the estimated datasets need to be evaluated based on another ETa measurement.

Itidel Alaya, Rim Zitouna Chebbi, Insaf Mekki, Abdelaziz Zairi, Nesrine Taoujouti, Amal Châabane, Hacib El Amami
Satellite Remote Sensing Applied to Landslide Susceptibility in the Andean Cordillera (33°27'–33°55' S)

The availability of remotely sensed data sources makes it possible to generate large-scale studies efficiently, accurately, and geographically scalable. Considering the remote sensing benefits and scope, we propose a methodology that integrates critical variables for a landslide susceptibility map preparation with an accurate hazard assessment in large areas. As a result, different areas prone to landslides are identified with precision in an efficient, safe, and accessible way through susceptibility map preparation.

Alejandro Montenegro, Pierre-Yves Descote, José Manuel Lattus, Luis F. Robledo, Gustavo Gattica, Xaviera Palma, Sergio Carvajal, Ivo Fustos, Mauricio Calderón, Wen Nie, Wenbin Jian, Jean-Baptiste Gressier
Investigating Accurate Water Body Extraction from Satellite Imagery Using Convolutional Neural Network with Water Indices

Water bodies like rivers and lakes are essential human, animal, and vegetation resources. Acquiring and analyzing these data are essential for better water resources and environmental management. In recent decades, many methods have been used to extract water bodies from remote sensing images. A critical way was using water indices such as normalized difference water index (NDWI) and modified normalized difference water index (MNDWI). Furthermore, extracting small water bodies (such as creeks) from satellite images is challenging and needs high spatial resolution images. However, there are several difficulties in using water indices in high spatial resolution images because of the limited spectral resolution. Most high spatial resolution satellites lack SWIR, which is necessary to calculate MNDWI. But, WorldView-3 overcomes this problem by having NIR and SWIR bands with high spatial resolution. This study used a Kaggle dataset called DSTL, which includes WorldView-3 images for the same region (but the dataset's provider obscures the location of these images) with 0.31 m, 1.24 m, and 7.5 m spatial resolution at nadir for panchromatic, multi-spectral, and SWIR, respectively. A convolutional neural network (CNN) was proposed to improve water body extraction from satellite images. In this network, three indices (normalized difference vegetation index (NDVI), NDWI, and MNDWI) were input layers to U-Net architecture. To evaluate this approach, the results were compared with the same U-Net architecture using RGB and all WorldView-3 bands as input layers, SegNet, and FCN-8. The Jaccard index was calculated as 90.7%, 90%, 89.3%, 85%, and 80% for U-Net with three indices, RGB, all WorldView-3 bands, SegNet, and FCN-8, respectively. The results show that using indices as input layers to U-Net improves the water body extraction, which is necessary to be accurate in several hydrological and water resources studies.

Anas Hesham, Dursun Zafer Seker
Landslide Susceptibility Assessment and Factors’ Selection Using the GIS Matrix Method (GMM) in Chefchaouen Province (Northern Morocco)

Situated in the Rif, a perimediterranean alpine chain, the province of Chefchaouen, has been the subject of multiple geomorphological studies for its hill slope dynamics because of the notable frequency and diversity of gravitational processes. The chain’s slope predisposition to these processes is due to its geological, morphological, and hydrological complexity and land use. Thus, to understand the distribution of this slope dynamic, the approach should be global by considering the abovementioned criteria in an analysis of the spatial pretension of these phenomena. This work aims to identify the factors responsible for the instability of the slope, which will allow the susceptibility assessment for Chefchaouen province using the GIS matrix method. Once the susceptibility map is produced, it is essential to evaluate its validity to assess the rate of correspondence between the distribution of landslides and the different levels of susceptibility. The inventory map and the susceptibility analysis are essential tools for future developments to anticipate and limit the damage related to landslides, especially since the production of an aptitude map for urbanization is being dealt with in the area under study.

Oussama Obda, Younes El Kharim, Ilias Obda, Mohamed Ahniche, Reda Sahrane
Remote Sensing Indicators for Assessing the Trophic Status of Barrier Lakes from Bahlui Catchment (Romania)

Maintaining good quality fresh water is essential to support its functions, including human consumption and environmental health. This could be possible through Sentinel 2 imagery provided by the European Space Agency. The analyzed barrier lakes are Parcovaci, Tansa, and Podu Iloaiei, which have an accumulated water volume of 5, 13.1, and 13.4 mil.m3, respectively. Monitoring water quality in these accumulations is a necessity to protect stored water from various forms of pollution, chlorophyll-a (Chl-a), total suspended matter (TSM), and turbidity (TU) being key indicators of the water’s ecological status. The present study analyzes thirteen Sentinel 2 images acquired between 2017 and 2020, for March–November, to evaluate water quality parameters. The water surface has been divided into three sections: tail, middle, and head. After analyses, it was found that the ecological potential was moderate or good, mostly maintained as moderate potential in terms of oxygen and nutrient regimes. The seasonality of the chlorophyll content, the amount of suspended matter, and the color are in accordance with the geomorphological features, the sediment budget, the land use, and the hydroclimatic parameters and with the main ecological and anthropogenic pressure factors of water quality. The result suggests that the indicators derived from remote sensing techniques represent an excellent information resource (significant R2 between 0.62 and 0.96) that can be used for complex and forecasting assessments of the trophic status of barrier lakes.

Iuliana Gabriela Breaban, Alexandra Petronela Stoleriu, Andreea Florina Stoleriu
Automatic Generation of Atlases for Social Data: Developing a Plugin for Qgis.3

The proposed plugin allows the generation of an automatic Atlas with layers of data with spatial references by crossing freely or supervising several thematic parameters in the form of a graphical interface. The Atlas aims to provide additional knowledge and skills as a map and diagram to elected representatives and planners to take into account the socio-economic dimension in planning policies and actions. It is developed in Python to be integrated directly into the environment of the Qgis 3 geographic information system. Toward the end, this tool offers the opportunity to the different users of cartographic production at the national level, such as The Centre for Social Action, Water Agency, Urban Planning Agency, Territorial Collectivity, Consulting Bureau to generate an Atlas of maps automatically. The Atlas could provide a panorama of several following thematic maps: (demography, employment, accommodation, disability, land use, etc.). Furthermore, Atlas allows a cartographer or a user to make a map or several based on a graphical interface. Finally, this will result in the constitution of a dynamic Atlas adapted to the needs of both the researcher of land management and planning. One of the advantages of this plugin is that it is quite possible to integrate geographic data into a web-mapping interface. It is also noted that this tool makes it possible to connect to a Postgres database to produce the maps remotely.

Abdelkrim Bensaid, El-mehdi Slaoui, Rachid Nedjai, Mohammed Al-Juhaishi
Contribution of Remote Sensing and GIS for Monitoring Land Use Change and Its Impact on Flood Risks in the Wadi Tessa Watershed

The study aims to assess changes in land use from multi-date satellite data and to estimate the impact of these changes on the risk of flooding in the Wadi Tessa watershed, a tributary of Wadi Medjerda, northern Tunisia. To monitor the effect of changing vegetation cover on flooding, multi-source and multi-date data were used. The methodological approach used is based on mapping using GIS and the processing of satellite images. The diachronic comparison of the supervised classifications of the Landsat satellite images used made it possible to determine the rate of land use change over 28 years, between 1990 and 2018. The results show that urban areas and scrubland experienced an increase in their surface areas with respective growth rates of (+ 0.08%) and (+ 10.64%). On the other hand, for other land uses, there has been a decrease in their surface area, with decline rates for forests (− 0.14%), agricultural areas (− 1.82%), rangeland (− 2.59%), and bare ground (− 5.83%). These results are very interesting since these land uses have given us an idea of worsening the flooding phenomenon, particularly in certain areas classified as sensitive. Furthermore, the comparison of the two flood risk maps shows an increase in the extension of the high-risk regions, which mainly cover urban areas, during this monitoring period (1990–2018).

Noamen Baccari, Hatem Chaar, Nadhem Brahim, Salwa Saidi
Diachronic Analysis of Land Use/Land Cover Impacts on Carbon Storage in Agadir City (Morocco)

The present study aims to evaluate and monitor the impact of urban expansion occurring between 1984 and 2019 in Agadir city—Morocco, on soil carbon storage. Landsat images acquired in 1984 and 2019 were processed and used to map and assess land use/land cover (LULC) change in the study area. In addition, the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model was used to map and quantify the soil carbon storage change during the same period. The results show a strong relationship between urban expansion and the carbon storage rate. Furthermore, a noticeable decrease in carbon stored from 1984 to 2019 was identified due to the conversion pattern from vegetation cover (e.g., grasslands and woodlands) to urban lands. Consequently, preserving and increasing green spaces within the study area are necessary to improve soil productivity and mitigate the negative impacts of LULC change on the local climate.

Ijjou Idoumskine, Ali Aydda, Abdelkrim Ezaidi, Omar F. Althuwaynee
Delineation of Groundwater Potential Zones Using GIS and Remote Sensing in Middle Moulouya Basin, Morocco

In Morocco, a semi-arid climate combined with a rising population has increased demand for scarce water resources. This study is to delineate groundwater potential zones (GWPZs) in the middle Moulouya basin, Morocco, using an integrated approach of geographic information system (GIS), remote sensing (RS), and Multi-Criteria Decision (MCDM) analysis. Five spatially distributed thematic layers include rainfall, drainage density, lithology, lineament density, and slope which were assessed according to their characteristics and relative importance in groundwater occurrence. These thematic layers and their sub-layers were assigned and normalized appropriate weights on the Saaty’s scale. Finally, a weighted sum overlay analysis tool was used to integrate the thematic maps to develop GWPZs. The study area’s delineated GWPZs are categorized into five different zones. According to the GWPZs, 4154 Km2 (29.2%) very poor, 1467 Km2 (10.32%) poor, 4476 Km2 (31.46%) moderate, 3158 Km2 (22.2%) good, and 971 km2 (6.82%) very good. The GWPZs’ map was validated by comparing it to the distribution of 722 water points and the results were found to be representative and reliable. This study provides a convenient method for delineating GWPZs, which will provide quantitative information for decision-makers to implement efficient management of groundwater resources.

Yasir Abduljaleel, Mustapha Amiri, Ali Salem, Mohamed Ghzal
Performance Aspects of Geographic Data Processing in NoSQL Databases

The continuous increase in the amount of collected data forces the development of new methods of more optimal processing. In this case, the use of relational databases is limited due to their insufficient performance and scalability. One of the alternatives is NoSQL databases, which can be easily scaled. Graph databases are NoSQL databases that use a graph structure where nodes and relations store and process data. Tree-structured data are better represented in graph databases. The intuitive use of graph databases in geospatial solutions allows the use of a model consisting of nodes (data points) and relationships (connections between points). This is one of the reasons why graph databases can be used, for example, to calculate routes between points in a road network. This article presents performance tests of geospatial functions available in the popular NoSQL databases, which have been adapted to work with spherical geometry, making it particularly useful for working with geographic data. Tests were carried out on two of the most popular, according to the DB-Engines ranking, open-source graph database management systems—ArangoDB and Neo4j. This article compares the performance of the query that calculates the shortest path between arbitrarily selected vertices. Yen's and A* algorithms have been tested. Tests have shown that the ArangoDB system is faster than Neo4j, in which the A* algorithm proved more efficient than Yen's. The authors also converted queries to the PostgreSQL relational database, the performance of which was compared with graph databases.

Wojciech Sarlej, Dominik Bartoszewski, Michał Lupa, Michał Wierzbiński
Prediction of Slope Failure Susceptibility of an Iron Ore Mine Using PCA and K-Means Clustering

Slope failure in mines is one of the most frequent accident events that cause damage to both property and life every year. This study uses remote sensing and GIS technique to predict and generate a slope susceptibility map of an iron ore mine area in India. First, the required remote sensing data and satellite images are collected. The final results of this study will help to find the vulnerable zones for slope failure, and eventually, this will help in effective land use planning to save the environment and lives. The basic data sources required to generate the final susceptibility map are various thematic maps such as land use, elevation, curvature. They are generated with the help of Digital Elevation Model (DEM) data collected from the satellite images of the study area. First, the weights for each thematic map are calculated using Analytical Hierarchy Process (AHP) method. Then, the PCA algorithm is implemented using PYTHON code to associate all the attributes to each pixel of the final slope susceptible map. Finally, each pixel of the final map is again classified into high, moderate, low, and very low slope susceptibility indexes using the K-means Clustering algorithm.

Suryajyoti Nanda, Raushan Kumar, Shantanu Patel
Digital Image Processing for UAV-Based Landslide Investigations

In recent years, Unmanned Aerial Vehicle (UAV) has increasingly become more common and practical in digital image processing for land mapping, including landslide investigation. Our work aims to analyze the displacement of the ground by digital image processing. The study area was the landslide site in Semarang State University Campus, Jalan Sekaran, Gunungpati, Semarang, Indonesia. We undertook this study by comparing the area’s elevation to investigate whether or not the area is prone to landslides using UAV. Flights took place in five different periods from September 2019–January 2020. Of five periods, two images representing the study area in September–October 2019 were investigated using DroneDeploy and calibrated using MyElevation. Digital terrain model (DTM) was obtained at the end of the investigation. The displacement result is ± 1 m. Although the displacement is relatively small, an area with a 1-m displacement is still considered susceptible to translational rockslide with the basal clay material. DroneDeploy can provide effective time in processing digital image data. In conclusion, this study shows that UAVs are essential tools in landslide investigation, and the displacement can be monitored, allowing early decisions and precautions to be made to prevent more tragic disasters.

Muhammad Mukhlisin, Aditya Putra Pradinawan, Hany Windri Astuti, Eni Dwi Wardihani, Rini Kusumawardani
Comparison of Original and Deep-Learning Enhanced Sentinel-2 Imagery in Mineral Prospecting Problems

Remote sensing methods based on satellite data with open access (as Sentinel-2 provides) are commonly used in geological applications. This paper examines whether Sentinel data with artificially enhanced resolution (to 2.5 m of 8 bands) can provide higher-quality results with mineral prospecting analysis. We believe that we have found deep-learning enhanced data to be the basis for getting considerably more valuable results. Furthermore, the enhanced resolution data allowed for an average of 8.55% more coverage, with the test area to be highlighted. We anticipate our research to be a starting point for the broader use of enhanced imagery in geological mapping.

Adamek Katarzyna, Michał Lupa, Andrzej Leśniak, Michał Wyczałek-Jagiełło
Debris Sliding Monitoring Using Permanent Interferometry Disperser Technique in the Chosica-Lurigancho District, Perú, 2020

Every year in the period from January to March, the constant rains produced by the El Niño phenomenon destabilize the terrain of the streams of the capital of the Lurigancho district, Chosica, located in Lima, Perú. Due to the heavy rains, many landslides occur in the different streams of Chosica. Although there are records of landslides every year, the last events recorded in Chosica occurred from January 14 to March 19, 2017. This study applies the Persistent Scattering Interferometry Synthetic Aperture Radar (PSInSAR) technique to estimate landslide displacement. Our study area includes 24 km2, emphasizing the Carrosio and Corrales streams. This research uses images of Terrasar-X, 19 scenes in ascending orbit and 20 scenes in descending orbit, from April 2020 to December 2020. This study has been worked with the PSInSAR technique, based on the InSAR time series. Considering the Chosica Landslide as a very slow-moving debris flow, this technology has acquired line-of-sight (LOS) deformation. First, the orbital displacement result has been obtained by processing with ENVI’s 5.3-Sarscape tool. Later, both orbits were spatially combined to obtain vertical (top–bottom) and horizontal (east–west) displacement using the ArcGis-Python tools. High consistency was achieved between the descending orbit and ascending orbit displacement results. A slight deformation of − 8 mm/year to − 21 mm/year was found in the area of interest in the Carrosio and Corrales streams, results obtained in the PSInSAR processing with descending orbit. While ascending orbit, possible areas prone to slipping of debris were identified with values of 8 mm/year to 10 mm/year. Subsequently, the integration of displacement data in ascending and descending orbits was carried out. As a result, we obtained a slight displacement of 0.10 mm/year to 0.16 mm/year of horizontal displacement and 0.10 mm/year to 0.19 mm/ year of vertical displacement. We conclude that the monitoring carried out throughout 2020 has not detected displacement. This research on monitoring Chosica área was made cause every year in this zone. We have heavy rain from January to March, so we need to monitor the area to prevent disasters. During the landslide monitoring of the year 2020, the analysis of results showed an insignificant displacement, and during the same period, no landslide events were reported by governmental authorities. Nevertheless, it is recommended to continue observing the area to prevent future debris flow in Chosica.

Lucero Rodas
SAR Image Despeckling Using a Self-supervised Learning Model

Synthetic aperture radar (SAR) images are often contaminated by speckle noise. Reflectors, on the ground, return constructive and destructive interference within each SAR resolution cell can result in a multiplication noise known as speckle. Such noise affects subsequent computer data processing and human visual interpretation. To effectively reduce the impacts of noise on signals, recent deep learning-based methods have shown promising results in natural images. However, applying such methods directly in a SAR despeckling task is not feasible where no ground truth data are available for training. To address this issue, we adopt a self-supervised training strategy, where we only look at corrupted (noisy) data without explicit image priors or a likelihood model of corruption. A deep neural network is applied to learn a mapping to each pixel's noisy version from its neighborhood pixels. We use a random donut masking strategy on training samples to prevent the model from learning identity mappings, significantly improving training efficiency. Since the noise has independent characteristics, our model can recover the pixels’ clean version correctly without a clean reference during training. We quantitatively assess our proposed method's performance using natural images with ground truth information. Experimental results demonstrate improvements compared to conventional noise filters. Qualitative evaluation is also conducted using real-world SAR images, and our outcome shows better visual quality than those from conventional filters. Our despeckling self-supervised model suggests the potential of using deep learning for SAR image filtering in the absence of ground truth.

Chuyang Liu, Ningbo Zhu, Xinyao Sun, Irene Cheng
Mapping of a Landslide Site with SAR Images in the Taurus Mountains

Remote sensing (RS) techniques help characterize the earth's surface. RS techniques can solve many engineering problems related to natural disasters. Landslides, essential agents of mass wasting and hillslope evolution, are common on mountainous terrains and cause loss of life and property. Interferometric Synthetic Aperture Radar (InSAR) is an effective way to measure land surface altitude changes and map topographic change on earth. Detection of movements in vertical and horizontal directions is needed to evaluate slope failure mechanisms. In this study, we analyzed the landslide after heavy rainfall and created coherence and phase maps with SAR data. We illustrated the potential usage of Sentinel-1 usage in a slow-motion landside site. This study can provide significant geomorphologic information about landslides. Our results show that monitoring landslides with InSAR data where traditional mapping opportunities are missing.

Aydın Alptekin, Murat Yakar
Using UAV-Based Photogrammetric Data for Pegmatitic Lineament Extraction in the Angarf Area (Zenaga Inlier, Morocco)

Data acquisition using unmanned aerial vehicles (UAV) has increased interest in the geological field. This instrument allows capturing of high-resolution images of the rock surface and the analysis of those datasets remotely. In this study, a lineaments extraction approach was applied to highlight the pegmatitic veins in the Angarf area (Zenaga inlier, Central Anti-Atlas, Morocco) using UAV photogrammetry. The photographs were acquired by Phantom 4Pro with a flight altitude set at 100 m. The resulting spatial resolution is about 3 cm/pixel. First, several preprocessing techniques were applied to the raw data to obtain a Digital Elevation Model (DEM) and an orthophoto. Then, a comparison between the two methods was conducted. The first consists of automatically extracting the lineaments from the shading of the DEM, and the second is based on manual interpretation to list the pegmatite veins directly from the aerial photographs. As a result, the approach using automatic extraction from shading provided little information since the elevation is almost invariant in the study area. This is in contrast to the manual interpretation of the orthophoto, where many veins were identified. Although the latter method is more time-consuming and relies mainly on human experience and capacity, it remains the most suitable for the case of our study.

Yousra Morsli, Youssef Zerhouni, Hamza Kadir, Soufiane Maimouni, Saida Alikouss, Amina Wafik, Zouhir Baroudi
Using SAR Data to Delineate Burned Territories in Central Kazakhstan

The study of fires and their consequences using remote sensing methods in the optical range is widespread. However, many works are devoted to forest fires, a little less to fires in arid areas. At the same time, even in arid regions, weather conditions do not always allow us to get a correct picture of the spread of fires in a sufficiently high spatial resolution (the first tens of meters). Our research uses the study area of the separating parts of the launch vehicles drop zone in Central Kazakhstan. To study the possibilities of remote sensing in the radio range, we used data from Sentinel-1 satellites to the same territory in Central Kazakhstan. In the course of experimental work, we found fresh burns in VH polarization seem to be the most contrasting. Therefore, we used Google Earth Engine to process the data. Since most fires in this area occur in June and July, we took the average image in VH polarization for April and August and subtracted one from the other. Due to the many factors affecting the radio range’s backscattering, we also added the difference between May and September average images to the previous one. Segmentation of the image by the mean shift method and classification of the obtained range of values into two classes using the natural breaks method gave a result comparable in accuracy with the use of indices in the optical range.

Andrey Karpachevskiy, Sergey Lednev, Ivan Semenkov, Anna Sharapova, Tatiana Koroleva
A Geo-Remote IoT Seismic Sensing Device, Made of Robust High-Sensitivity TENGs

This work presents the best TENG (Triboelectric Energy NanoGenerator) candidate to be used as a seismic sensor and integrated into any global seismic network. The most optimal one out of six different compositions’ was made of PPA-PEI: PVDF with 10% of PPA, which is flame retardant and has a very low dynamic resolution. Oscillations with an Instrom electromechanical machine in the range of (0.5–50 Hz) were generated and tested with the PVDF-based TENG. An estimated sensitivity of 250 pulses/s was calculated, and the electrical power density was measured at 100 mW/m2. Pulses were Wi-Fi transmitted following the LoRA protocol. After being analyzed, they were received and decoded in The Things of Stack platform (TTS). Simulations of real ground motions caused by seismic waves were performed by hand-tapping the surface of a table on which a TENG was fixed with a calibrated metallic weight (inertial mass) resting on its upper surface. Pulses generated by the TENG were detected with a high-resolution DAQ, and the frequency spectrum was studied. In addition, they were tested in a triaxial vibrating platform with microelectromechanical sensors (MEMS), giving very similar results. The possibility that hundreds of these low-cost TENGs are integrated into seismic networks, and that frequency spectra and pulse shapes generated by seismic waves can be monitored anywhere in the globe makes this application one of the most relevant in the geo-remote sensing field.

José Sánchez del Río Sáez, Abdulmalik Yusuf, Ignacio Astarloa Olaizola, Lucía Urbelz López-puertas, José Luis Jiménez, Vanesa Martínez, M.ª Yolanda Ballesteros, Romano Giannetti, José Benito Bravo Monge, Juan Vicente Cantavella Nadal, Carlos González González, Xiaosui Chen, De-Yi Wang
Investigation of Probable Impacts on Land Cover Transition in Istanbul Driven by Planning the Canal Istanbul and the Great Istanbul Tunnel Projects

Population growth has caused enormous transportation problems in Istanbul, joining Asia and Europe. As a result, three bridges and two tunnels were built between two continents, and the Canal Istanbul and the Great Istanbul Tunnel projects are planned to be constructed to overcome traffic problems. The paper's main objective is to determine the urban sprawl triggered by the new transportation projects in Istanbul. Therefore, cellular automata-based simulation models were created for 2040 using the SLEUTH Urban Growth Model. According to the results, Istanbul will continue to sprawl onto agricultural and forest areas, and the new projects, especially Canal Istanbul, can accelerate urban sprawl twice as much.

Ismail Ercument Ayazli, Ahmet Emir Yakup
Development of an Object-Oriented Geographical Data Model for the Management of SPEA

Protected areas have preserved their importance from past to present; these must be preserved due to their historical, cultural, economic, social, and natural characteristics. Protected areas in Turkey are managed under the powers and responsibilities of different institutions within the framework of the legislative provisions. It is aimed to develop an object-oriented geographic data model to protect, manage and transfer the Specially Protected Environment Area (SPEA), which is one of the protected area types, to future generations. In line with this purpose, experts related to the study were included in the study to determine the current situation and problem. The study is handled under two elements. First, a semi-structured interview form was made with the expert staff. Expectations, problems, and alternative solutions were tried to be obtained. With this research, an object-oriented SPEA geographic data model was designed as a result of the information obtained from experts and the literature research. In the development of the model, international visionary studies and standards such as LADM, INSPIRE, ISO, and Cadastre 2014 and Beyond were examined. However, the national-scale TNGIS developed in parallel with these studies was discussed, and the model was developed accordingly. UML schemas were used to design the object-oriented model. The use of UML schemes in GIS applications has gained momentum recently. Thus, a geographic data model, including spatial and attribute data, has been designed for SPEA. As a result of the study, it has been determined that protected areas, considered the common property of all humanity, should be protected and transferred to future generations in a good way. Currently, it has been determined that no TNGIS and e-government applications belong to SPEA. It has been determined that this situation may deepen the existing problems in SPEA management. For this reason, object-based geographic data model design has been realized through UML diagrams integrated with TNGIS, and a GIS data model application has been made. The spatial and attribute data of the study area were presented, the topology was established, and the model was implemented. The data were obtained from the study carried out with the General Directorate of Nature Conservation and National Parks, the Ministry of Environment and Urbanization, and experts. Thus, it was possible to make spatial analysis and query. The importance of managing SPEA in a common geographical database throughout the country was emphasized to establish an object-based SPEA management model. In order not to deteriorate the protected areas with structuring under the pressure of the city over time, the importance of effectively managing these areas with a single responsible organization in the organizational sense has been mentioned. In addition, it was stated that a data theme, such as the protected areas data theme in INSPIRE, should be defined in TNGIS.

Mehmet Özgür Çelik, Yakup Emre Çoruhlu
Comparative Analysis of the Spectral Response of Vegetation for Monitoring the State of the Landscapes of the Protected Area of Delta Del Cauto (Cuba)

Using satellite images and indices to determine qualities of the natural environment components enables today to identify their behavior and evaluation while facilitating diagnosis or predicting trends and projections of their behavior. The vegetation cover is essential for man; hence, there are multiple and substantial resources, methods, and technologies for studying and conserving this heritage. The use of indices to show the spectral behavior of the coverage is becoming increasingly common in many pieces of research about the geographical environment. The article analyzes the study results of the spectral response of vegetation in the main communities of the Cauto Delta Fauna Reserve, which is necessary for follow-up studies, vegetation mapping, and optimization of territory management. For this purpose, the temporal behavior was analyzed from the spectral response of the vegetation cover using the normalized vegetation index (NDVI) of Sentinel-2 images. As a result, the spectral responses of the six plant formations in the area were obtained. Our calculations indicate that the average spectral response of plant communities varies in the range of − 0.01 to 0.83. These values are present in the communities of saladares and secondary forests, respectively. Months and years of the highest and lowest spectral response of NDVI were also identified.

Alejandro Oliveros Pestana, Khlebosolova Olga Anatolyevna
Integration of Cloud and Desktop Platforms to Support Analysis of Big Geospatial Data Time Series

Despite the computing power growth of the cloud-based platforms providing the opportunity to process the big amounts of remote sensing data, there is still a need to process and store some kinds of data locally. During the last several years, scientists have been interested in makings to make the popular open-source GIS application QGIS and the most popular cloud-based platform Google Earth Engine (GEE) friends. However, today it is not comfortable to use different processing platforms because of their data format differences or some long converting data manipulations. Some platforms suggest their cloud-based storage services use, but some restrictions include limited storage space, upload/download speed limitations, or data format differences. This research uses the GEE as a well-designed platform with often updated remote sensing data storage, processing tools, and algorithms for interdisciplinary research using the cloud and desktop data processing opportunities. The main idea is to create a well-designed infrastructure that can be more flexible than separately used cloud and desktop platforms. An integrated cloud-desktop processing infrastructure is based on GEE cloud performance via the Python API, QGIS as a powerful desktop GIS software, and PostgreSQL with PostGIS extension to store and analyze the results of cloud-desktop processing of remote sensing data locally by database management system (DBMS). Integration of the cloud-desktop processing has allowed for increasing the data processing speed, ensuring the operational usage of the representative satellite observation data, and processing long observation series without using local capacities without needs.

Ivan Rykin, Evgeny Panidi
Comparison of Semantic Segmentation of Point Clouds Obtained from Different Sensors Using Deep Learning

Deep learning methods have been successfully used in image processing and computer vision. Point cloud semantic segmentation is also a current study subject where deep learning is widely used. In this study, Semantic3D, a terrestrial laser scanning data, and Dublin City, an airborne laser scanning data, were used. Random sampling and an effective local feature aggregator (RANDLA-Net) were used as the segmentation algorithm. Precision, recall, F1 score, and overall accuracy were used as evaluation metrics. The overall accuracy is obtained as 0.882 in the Semantic3D dataset and 0.896 in the Dublin City dataset.

Muhammed Enes Atik, Zaide Duran
Geo-ontologies and Their Role in Integrating Big Spatiotemporal Data and Knowledge Management

Managing Exploration and Production (E&P) data and establishing the connectivity between Geology and Geophysics (G&G) domains are vital in the upstream petroleum businesses. These challenges can affect the data integration during the interactive interpretation of exploration data. In addition, the E&P data are big in size and scale; new file storage systems are needed. Exploring the basin ecosystem and managing knowledge through holistic data modeling studies are innovative research strategies. A single data anomaly attributed to seismic data can yield ambiguous results. To establish the G&G connectivity, we explore geo-ontologies to motivate data modeling methodologies with a case study in the Nile Delta basin ecosystem. Data mining and interpretation artifacts are added solutions to discern data patterns and unlock latent geological knowledge. We have proposed an integrated digital petroleum ecosystem framework, collaborating with various multidimensional data schemas built from multiple domains of upstream exploration businesses. The new integrated framework can facilitate the E&P entities and accrete new prospect volumes with drillable assets, minimizing the exploration and field development risks.

Shastri L. Nimmagadda, Andrew Ochan, Said Hanafy, Torsten Reiners
Spatio-Temporal Mapping on the Distribution of Volcanic Products as Construction Materials Using ASTER Images at Southeastern Part of East Java (Indonesia)

The southeastern region of East Java, Indonesia, named Jember Regency, is known as the city of “a thousand volcanic products dune”. Volcanic product, which is generally a dune containing construction materials (sand as a matrix and stone as a fragment), has been widely mined by the local communities as a building material and a foundation for road construction. This study aims to map the distribution of volcanic products from 2016 to 2019 using Aster satellite imagery to analyze their spatiotemporal changes. So that within about three years, the change of construction materials distribution due to the mining activities by local communities can be analyzed. There are two volcanoes in the northwestern and eastern parts of the study area, known as Mt. Argopuro and Mt. Raung, respectively. The field survey results indicated that a few numbers of the product originated from lava flows characterized by columnar joints of andesite and the presence of tuff or lapilli (product of volcanic ash), which is utilized for the concrete brick material by the local community. However, the volcanic product was mainly found as lapilli with some volcanic bomb mixed. A petrographic observation was used to identify the mineral composition and texture and verify the rock types. This study gave a new idea to quickly map hundreds to thousand of volcanic products and report the change in their volume as construction materials.

Mohamad Nur Heriawan, Fajar Djihad, Asep Saepuloh, Haeruddin
Study of Water Mass Change Impacts on Water Salinity and Steric Fluctuations in the Caspian Sea

The water level fluctuation associated with water density changes, known as steric fluctuation, is an essential contribution to total sea-level fluctuations and the principal reason for water circulations in the Caspian Sea. Water salinity is one of the main parameters controlling water density. Aside from regular seasonal changes, as an additive parameter, water salinity could have a long-term cumulative impact on the water density and, therefore, on the steric fluctuations. Water mass variations mainly control water salinity rate; it is particularly confirmed in closed inland water bodies. In the absence of water salinity data, utilizing altimetry-derived water level anomaly, we estimated a time series of salinity variation in the Caspian Sea. According to water density changes, steric fluctuations are estimated for four decades (1981–present). The results show that water salinity variations have changed the seasonal amplitude of steric fluctuations, decreasing from 1981 to 1995 and increasing from 1995 to the present. This change exceeds 0.15 mm, equaling 2% of the total seasonal amplitude, during the study period. Considering the continuation of the lake level drop over the last 25 years, water salinity may experience unprecedented increases, resulting in increasing seasonal amplitude of steric fluctuation, which critical changes could follow in water circulation.

Ayoub Moradi
Identification of Art Styles of Tectonic Maps Using Machine Learning

The paper aims to verify the possibilities of the Orange software for defining and identifying artistic styles of tectonic maps using machine learning techniques. A set of tectonic maps obtained from online sources was tested so that the selection of maps was not influenced by the data capture method. The collected maps differ in color and design mainly. The maps evaluated were included in the analysis of the artistic style in the Orange software as pictures. The Painters embedder was applied, which has the most significant potential for clustering maps according to the artistic style of all embedders in the Orange. All maps were cartographically described and subjected to a “map-use” experiment to obtain a subjective evaluation of artistic style by 30 map readers. The obtained evaluation was compared with the assessment of the artistic style using neural networks from Orange, which was used to determine how maps are grouped according to art map style using already integrated neural networks with hierarchical and non-hierarchical clustering methods. The results of the user evaluation in the experiment were compared with the results of the Orange evaluation. The classification of tectonic maps according to the map style and the results from the Orange embedder were compared. The paper results in a recommendation for the creation of a neural network to evaluate the artistic style of not only tectonic maps. Thanks to the created neural network, searching for maps of an art style identifies easily. The paper reveals an original way of identifying the artistic style of the map to support the interpretation of information in the map.

Vit Vozenilek, Martin Sadilek
Comparison of Vegetation Indices of Crops from Satellite Images PerúSAT-1 and UAV

Vegetation indices mainly identify plant health conditions, such as bioindicators monitoring crops using satellite images. The most used indices in the agriculture sector are Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Soil Adjusted Vegetation Index (SAVI). These indexes can be obtained from the visible and infrared bands from sensors aboard platforms such as satellites or Unmanned Aerial Vehicle (UAV). The present research was carried out on an area of horticultural crops in the Carabayllo, Lima (Peru) district. Images from the Naomi sensor of the PeruSAT-1 satellite and the MicaSense Altum multispectral sensor of UAV are used, where PeruSat-1 is an Earth Observation Satellite that belongs to the Peruvian government, and it is operated by Comisión Nacional de Investigación y Desarrollo Aeroespacial (CONIDA). These images from the study area were obtained at different wavelength amplitudes for each spectral band. The best environmental conditions were considered, such as the low cloudiness and proximity of the capture dates of both sensors, to reduce the spectral variations of the crops and their phenological state. However, it is important to convert digital levels to surface reflectance levels for the same radiometric scale for spectral response analysis with both sensors. The images underwent radiometric and geometric correction, then the generation of vegetation indices to obtain segments with similar spectral characteristics for each class, from which the values were extracted using random points (50 points per class). The results are analyzed using a Pearson sample linear correlation, where it is observed that the vegetation indices obtained from PeruSAT-1 and UAV images show a positive correlation around r > 0.8 for the variables of NDVI, SAVI, and EVI.

Tulio Wilfredo Chávez, Rodolfo Moreno, José Pasapera, Niltón Perez
Analysis of Spatial Information Technologies Education in Jordan and Algeria

This study focuses on promoting spatial information technology education within the scope of the “Earth Observation Tools for The Promotion of Digital Economy (ERODITE)” project, sponsored by the Erasmus + Capacity Building in Higher Education program. An overview will be given on how the relevant Earth Observation technologies are currently offered within the official courses of relevant education degrees in Algerian and Jordanian Universities and the way they can be updated to include implementations for the digital economy, determining new job opportunities and educational enhancements and some issues such as gender equality. One of the first tasks that have already started is to describe the current status of geospatial information technologies in the curriculum of universities in Algeria and Jordan by evaluating their staff, facilities, and infrastructures, including the strengths and weaknesses of the relevant departments and the opportunities that were discussed. According to the findings, Jordanian universities have insufficient appropriate academic staff and EO-related content. In contrast, Algerian universities and institutions appear to emphasize vocational and technical education more than theoretical and research aspects of EO-related content.

Nawras Shatnawi, Nusret Demir, Maria Tsakiri, George Hloupis, George Vergos, Mohammed Obaidat, Habib Mahi, Abdellatif Megnounif, Mourad Korichi, Bara Al-mistarehi

Applied and Theoretical Geophysics

Frontmatter
Comparison of Migration Methods on Seismic Reflection Data from the Marmara Sea and Its Interpretation Using Active Tectonics

Interpreting multi-channel seismic reflection data requires several modifications for improvements and the association of data with geology. This editing and improvement process is called seismic data processing. Seismic migration, the basis of this study, is a seismic data processing step that moves the seismic reflections associated with strong dips and refraction scattering in the data to their accurate geological locations in the time and depth domains. This study aims to apply and compare the different seismic migration methods on two lines of 2D multi-channel marine seismic reflection data collected at Central Basin and Çınarcık Basin in the Sea of Marmara in 1997 by R/V MTA Sismik 1. Following the application of migration methods on both pre- and post-stack sections and comparing the results, 2D Kirchhoff pre-stack depth migration (PSDM) sections are interpreted in terms of active tectonics. In the Central Basin, it has been found that the basin structure is formed by N-W striking left lateral to oblique-extensional faults, which are terminated in the N and S by en échelon segments of oblique-extensional faults. In the Çınarcık Basin, “V” shaped sagging sedimentary layers consisting of turbidites, the main Marmara fault, and its related faults are observed. Concluding the investigations, new faults were observed in addition to those observed in previous studies both in the Central Basin and the Çınarcık Basin. These new faults are compatible with the tectonic features of the region.

Mehmet Ali Üge, Ali İsmet Kanlı
Seismostratigraphic Characterization of the Rharb Basin’s Post-nappe Series (N-W Morocco)

The Rharb basin is a tectonically active zone between the Rifaine fold and thrust belt and the western Moroccan Meseta. It is made up of a set of structural Miocene tectonostratigraphic units witch evolution is nowadays debated. Compilation of an array of industrial seismic profiles calibrated with well-log data enables us to establish the sismostratigraphic framework of the Miocene units. The new three-dimensional model of the substratum (nappe prérifaine) of the Rharb basin shows an arcuate and diapiric-like structure linked to the southwestern extrusion of the prerifaine nappe. The most associated deformations are normal extensional faults with a detachment surface located mostly on the “prérifaine” layer hinges. The identified sismosequences are controlled by prerifaine nappe extrusion and Miocene/Plio-quaternary relative sea-level fall.

Fatima Zahra Sbihi, Abdelaziz Mridekh, Mohamad Hafid, Abdallah Ait Salem, Malika Killi, Mohammed El Bouhaddioui
The Death Throes of the Tethys Seaway and the Birth Pangs of the Red Sea: The Geodynamics of the Levant

As the Tethys Seaway closed in the tectonic domain of the Levant, it left behind two branches. The continental collision occurs in the eastern branch along the Bitlis–Zagros suture. Subduction still prevails along the western branch between the Anatolia–Balkan sections of Eurasia, where the last remnant of the Tethyan maritime domain persists. It seems that differences in the northward plate motion of Arabia as its convergence with Iran–Anatolia gradually changed from subduction to collision took place, leading to the break up of the Gulf of Aden and the Red Sea. Concurrently, the subduction along the Hellenic convergence in the west was associated with extensive rollback that broke up the Aegean Sea as its back-arc basin, and the rollback of the deformation front dragged Anatolia westward. It seems that the closure of Tethys Seaway led to the emergence of the Aegean Sea, the Red Sea, and the Gulf of Aden.

Yossi Mart
Resistivity and Seismic Refraction for Solving Groundwater-Related Problems: A Case Study from North Oman

Geophysical methods are very widely used for groundwater exploration and characterization. In Sultanate Oman, with the increasing demand for groundwater, geophysical methods are increasingly involved in exploration activities and solving problems relevant to this vital natural resource. In this study, seismic and resistivity methods were used to solve problems related to groundwater in Bidbid, Northern Oman. Falaj Mazra in Bidbid, the ancient irrigation channel, receives surface water from Wadi Samail’s water running from the base flow when the wadi is dry. Four pipelines were installed and buried over the wadi channel, parallel to its course. After several years of flow, the falaj has dried up. Geophysical methods have been invoked to investigate whether the pipelines’ influence on the falaj system caused its dryness. Resistivity and seismic refraction have revealed that the water table has dropped below the bottom of the falaj. Landsat images collected over the area have shown a significant increase in agricultural activities during the past decade. Consequently, the actions led to a considerable rise in groundwater exploitation. In addition, demographic statistics over the past decade also inferred that the overexploitation of groundwater by the increasing population has contributed to the decline of groundwater reserves and water table. In conclusion, based on the results from seismic and resistivity, the falaj dryness is attributed to the water table level drop caused by the increasing population and its associated agricultural activities.

Mohammed Farfour, Talal Al-Hosni
Pan-African Structures Evidence of Maghreb Domain (North Africa) Revealed by Aeromagnetic and Gravity Data: Special Focus on the Tunisian Territory and Surrounding Area

Pan-African structures of Maghreb (North Africa) have been studied using aeromagnetic and gravity data compilation. Special attention will be placed on the signature of these structures in the Tunisian territory and surrounding area. The comparison between magnetic analysis results and the gravity study shows a perfect agreement between the two approaches. The basement puzzle configuration and the deep-rooted fault systems have been demonstrated for the Tunisia study case. At least two Pan-African major lineaments have been revealed with different magnetic signatures: the NW–SE North Saharan Flexure and the N–S Axis. The N–S Axis can be connected to N–S mega-faults affecting the Hoggar–Tebisti Archean–Paleoproterozoic craton.

Hakim Gabtni
Postulated Precambrian Basement of the Iraq Southern Desert: A New Look Utilizing Magnetic Data

The Iraq Southern Desert (S.D.) forms part of the stable shelf of the Arabian Platform, characterized by a thick and generally non-magnetic sedimentary cover that overlies the Precambrian and reworked Proterozoic basement. Airborne magnetic survey data are utilized to study the magnetic intra-basement and potentially more profound crustal variations in S.D. A third-order polynomial trend is removed that represents the regional field. The calculated residual field map shows high amplitude negative anomalies in some isolated locations. These anomalies lie on the northeast and north–south pervasive magnetic lineaments that favorably correlate to postulated tectonic extension. The lineament structure may reveal extensional tectonics that caused latterly differential subsidence within the shallow crust in a similar form to the well-known N–S trending Al-Ma'aniyah Depression in the extreme northwest of S.D. suggesting the occurrence of structural lows or proximal sub-basin systems. The residual magnetic anomalies are inseparably correlative to the structural lows. The reliable Euler deconvolution approach, which was recently proposed by Melo and Barbosa (2020), is applied to the total, regional, and residual magnetic products for depth estimation. The estimated depth, based on 38 selected anomalous areas on the residual map and assuming contact and dyke source geometries, is between 4 and 9 km.

Hayder Al-bahadily, Ali M. Al-rahim, Andrew Long
The Hadean–Cenozoic Vertical Growth of the Continental Crust on Seismic and Geological Research

The relevance of the study is caused by the need to show the real evolution of the continents according to planetary seismic data. For the first time, the German geophysicists H. Closs and Ch. Behnke made a deep seismic section of the planet’s Earth's crust at latitude 40° N—in 1963. The origin and growth of the American and Eurasian continents in deep depressions (of deep to 50 km) of the Earth's mantle are visible in the section. Later, this discovery was subsequently confirmed in various parts of the planet. The main peculiarity of the continents’ formation is clearly expressed in these sections—from the Hadean to the Cenozoic time. The lower layer of the continental crust was formed in the Hadean era (4.4–4.0 billion years ago). It is represented by metabasalts and peridotites, which were later transformed into crystalline shales and amphibolites. The layer thickness is 10–35 km, and the density of rocks is 2.75–3.05 g/cm3. The middle layer of the Earth's crust was formed in the Archean–Lower Proterozoic time (4.0–1.7 billion years ago). Granites and gneisses represent it. The layer thickness is 5–20 km, and the density of rocks is 2.5–2.75 g / cm3. Finally, the upper layer of the Earth's crust was formed in the Proterozoic–Phanerozoic time (1.7 billion years to 1 million years ago). Carbonate, sedimentary–metamorphic rocks, and intrusive rocks of different compositions represent this layer. The layer's average thickness is 3 km, and the density of rocks is 1.8–2.5 g/cm3. The proof of the vertical growth of continental earth crust in the deep depressions of the upper mantle is a new important knowledge in the Earth sciences.

Anatoly Zhirnov
Integration of Sequence Stratigraphy, Facies, and Geotemperature Analyses in the Study of Hydrocarbon Prospectivity of Bornu Basin in Northeastern (Nigeria)

As Nigerian drilling operations expand into more challenging and costly operating environments of deep frontiers, there is a need for critical analyses of facies, stratigraphy, depositional environments, prospects, leads, geotemperature, and abundant hydrocarbon windows of the inland basins. In this study, the hydrocarbon prospectivity of Bornu Basin has been determined by integrating the above studies and reassessing the key petroleum play elements and prospects in the Seloken field. The facies interpreted from gamma ray and resistivity logs are sandy shale, shale/sand heterolithic, hemipelagic shale, shaly sandstone/coarse-grained sandstone, and sandy shale/coarse-grained sandstone facies, which are associated with Bima and Gongila Formations, Fika Shale, Kerri–Kerri, and Chad Formations, respectively. The log also interpreted the depositional environments, and the result shows that the sedimentary facies were deposited in various settings ranging from fluvial through transitional to shallow marine environments. Seismic and log data were used to analyze the sequence stratigraphy, and a genetic model was used to delineate the sequence boundaries. Three depositional sequences, including three maximum flooding surfaces (MFS), were identified. Three significant reservoirs corresponding to the sand members of the Gongila, Kerri–Kerri, and Chad Formations were placed, and these lie within the lowstand system tracts (LST) and highstand system tracts (HST). Fika Shale and shale members of the Gongila Formation found within the transgressive system tracts (TST) constitute the source rock. In contrast, the shale members of the Gongila, Kerri–Kerri, and Chad Formations, which lie within HST, are the seal. Depth surface maps were generated from seismic data, and two prospects and eight leads were identified across the maps. Seismic facies were interpreted from seismic data. The facies identified are named D, E, and Bh, which correspond to continuous high/low amplitude, low amplitude/high impedance, and high amplitude discontinuous, respectively. As E facies ranks highest, the Bh facies ranks lowest. The root mean square (RMS) and the sum of the negative amplitude attributes were run on the generated surfaces. The results show localized amplitude anomalies within the surfaces of the formations. The map generated from the above results shows clusters of bright amplitude which indicates traces of hydrocarbons within the shapes. These amplitudes are highest in the Kerri–Kerri Formation and are identified as prospective zones. Geothermal gradients of the field were calculated from the bottom hole temperature data, and they range from 3.4 °C/100 m to 4.0 °C/100 m with an average of 3.65°/100 m and a standard deviation of 0.01 °C/100 m. Temperature values of shale units of the formations calculated from geotemperature equation range from 30.99 to 202.45 °C. This shows that some shale units of some formations are thermally mature to cook petroleum. The hydrocarbon window model generated from the mathematical equation indicates that the oil window is between 1178.1 and 2547.9 m, while the gas window is between 2547.9 and 5424.7 m. This study shows a hydrocarbon prospect in Seloken Field, Bornu Basin, because most of the petroleum system elements are in place.

Eliseus Akpunonu, Onochie Okafor, Solomon Okeke, Godwin Oboh, Adolphus Omeokachie, Didi Chekwube, Celestine Obi
Use of Ultrasonic Waves for the Evaluation of the Unsaturated Zone Hydrodynamic Parameters: An Example from Merguellil Basin Downstream of El Haouareb Dam (Central Tunisia)

Groundwater recharge estimation, which is usually required for good water resources management, is usually based on predicting the unsaturated zone hydrodynamic properties. This study uses the ultrasonic method to assess the soil hydrodynamic properties of the unsaturated zone in Merguellil Basin downstream of El Houareb Dam (central Tunisia). This method is considered a fast indirect tool to determine soil physical parameters and spatial variability. These data are required to estimate infiltration rates in the unsaturated zone and its evolution over time and space. Several measurement points were chosen on the subsurface downstream of El Houareb Dam. Models were produced using artificial neural networks, correlating the selected physical parameters (ultrasonic velocity, density, and lithology) with the soil hydrodynamic properties (effective porosity and water content (Wc)). For this purpose, 16 soil samples were taken from 4 stations of the basin downstream. The obtained results illustrated the behavior of the ultrasonic waves controlling soil physical properties of the subsurface, which shall be subsequently valorized in simulating infiltration and groundwater recharge.

Mohamed Abdelhedi, Dhouha Ben Othman, Habib Abida, Hakim Gabtni, Chedly Abbes
Prediction of Late Paleocene Source Rocks in Lishui Sag, East China Sea Shelf Basin

For most oil and gas fields, it significantly predicts the spatial distribution of hydrocarbon source rocks. Generally, the evaluation of source rocks depends on geochemical analysis and a significant quantity of wells. However, for offshore exploration areas, the prediction of source rocks is limited by the wells’ data. With the development of 3D seismic exploration technology, combining wells and seismic reflection data can obtain important information to forecast source rocks. We describe an integrated method involving non-standard processing of seismic reflection data with sedimentary facies analyses to control the prediction accuracy of source rocks. And we applied the method to our study area, Lishui Sag, located in East China Sea Shelf Basin. The results show that the seismic reflection of source rocks in this area is characterized by low frequency and high amplitude. And source rocks mainly distribute in the Yueguifeng and Lingfeng Formation, characterized by a high percentage of mudstone. Source rocks in the East Subsag and South Subsag are few and thin because these two places are far away from the sediment source. The thickness of the source rocks is less than 200 m. On the contrary, the thickness of source rocks in the West Subsag is the largest in the area, reaching 500 m. By comparing the literature results, we believe combining sedimentary facies analyses with geophysical data can provide reliable information on the spatial distribution of potential source rocks.

Na Li, Jinliang Zhang, Lianjie Li
Analysis of Geoelectric Data Through Machine Learning Algorithms for Waste Leachate Detection

Electrical resistivity tomography (ERT) is an effective method for detecting the leachate plume due to the plume's very low resistivity values. However, it is well-known that identifying contaminated areas in landfill sites based only on the distribution of electrical resistivity values is highly ambiguous, especially in the presence of clayey soils, given the low resistivity values that generally characterize both wet/saturated clays and contamination plumes. To overcome this problem, the ERT method is usually combined with the induced polarization method to derive useful information on leachate detection from the resistivity, chargeability, and ratio values. In this study, we developed a tentative methodology for leachate detection based on clustering analysis of geoelectrical data. The k-means algorithm was applied to perform a cluster analysis of the inverted resistivity and chargeability data acquired in a landfill site in the Campania region (southern Italy). This site is in a geological context characterized by silty-clayey deposits, with intercalations of graded sandstones from the Miocene age. Therefore, it represents a meaningful test bench for investigations integrating different geophysical datasets.

Ester Piegari, Valeria Paoletti
Study of the Agricultural Land Salinization by Subsurface Geophysical Methods in the Merdjadja Palm Grove Touggourt Region (Algeria)

The present work is devoted to applying geophysical methods to study the agricultural land salinization in a small palm grove in the Touggourt region located northeast of the Algerian Sahara. Several causes have made this region favorable to the accumulation of salts at the surface and at depth, such as its tectonics, low altitude, geomorphology, the direction of its water flow, and lithology, which are added anthropological practices that accentuate the phenomenon. The study began with an electromagnetic survey, whose results showed the presence of a conductive anomaly with an N–S direction occupying most of the western part of the palm grove. An electrical survey was then carried out to identify this anomaly, and several Schlumberger soundings were conducted. The processing and interpretation of the electrical resistivity data confirmed the high mineralization of the groundwater and the contact between the shallow water table and the Mio-Pliocene water table used for irrigation, thus explaining the poor physicochemical quality of the water in the latter.

Madina Khelifi Touhami, Seyfallah Bouraoui, Mohand Ou Abdallah Bounif, Mohamed Walid Belgroun, Oussama Belaroui
Porosity Prediction from Seismic Using Machine Learning: Example from North-West Shelf Offshore Australia

Porosity has always been an essential property for determining reservoirs’ volumetric; however, determining porosity with an acceptable range of certainty carries many challenges. The deep-water Plover reservoir in Poseidon area, North Western Australia exhibits a special depositional environment, unique interior structure, and a complex porosity distribution that make predicting reliable reservoir properties challenging. This study aims to enhance the characterization of the Poseidon reservoir in terms of porosity using a combination of reservoir geophysics (seismic attributes and petrophysics) through machine learning (ML) techniques. Three methods of porosity estimation from seismic data have been implemented and compared: (1) multi-linear regression (MLR), (2) probabilistic neural network (PNN), and (3) deep feed-forward neural networks (DFNN). The seismic data available is a post-stack volume inverted to derive P-impedance. After the inversion, training data at well locations were analyzed, and statistical relationships were established between the porosity log, the seismic data, and the seismically derived P-impedance. Cross-validation was used to assess the reliability of the derived relationships. The probabilistic neural network (PNN) showed promising results far better than other comparative methods. Apart from PNN, the deep feed-forward neural network (DFNN) was also tested but gave limited success due to the scarcity of labeled data. The lack of labeled data has limited the optimum prediction of subsurface properties to a large extent. The predicted porosity from PNN has revealed geological features that otherwise are not seen in simple seismic inversions or seismic attribute analysis.

Mohamed Al Sarmi, Mohamed Farfour
MAVO: A Free Matlab-Based AVO Analysis and Interpretation Application

Amplitude variation with offset (AVO) methods are commonly used to study seismic amplitude variations with respect to offset or angle and relate them to fluid and lithology types and changes. MAVO is a free Maltab-based program for AVO analysis and interpretation. The program allows the user to carry out AVO theoretical and real data analysis and interpretation. With MAVO, one can invert pre-stack gathers for AVO attributes such as intercept and gradient. The intercept and slope are combined to produce other AVO attributes related to fluid, such as different fluid factors and scaled Poisson ratio. As an application, Vp, Vs, and density models from the Marmousi II model are used to compute the AVO intercept, gradient, P-wave reflectivity, and S-wave reflectivity. The latter AVO attributes are combined to produce the first fluid factor (FF1) proposed by Smith and Gidlow (Geophys Prospect 35:993–1014, 1987), the second fluid factor (FF2) presented by Fatti et al. (Geophysics 59:1362–1376, 1994), and the third form of the fluid factor (FF3) proposed recently by Farfour and Castagna (A new expression for fluid factor using AVO intercept and gradient. Expanded Abstract in SEG21 91st Annual Meeting, 2021). The above attributes showed an excellent ability to detect the different hydrocarbon-saturated reservoirs in the Marmousi model. Therefore, MAVO will be an excellent tool for students and new AVO practitioners to practice AVO attributes and their uses for hydrocarbon-saturated reservoir detection.

Mohammed Farfour

Earthquake Seismology and Geodesy

Frontmatter
Prospects for Combining a Geodetic Angle Refractometer and an Electronic Tacheometer to Improve the Accuracy of Angular Measurements

The atmospheric refraction effect significantly distorts the results of conventional geodetic measurements. The error due to the vertical refraction can be one hundred times greater than the instrumental error of an electronic tacheometer. Therefore, GNSS measurements do not always obtain reliable results. Furthermore, the hardware methods of refraction determination are complicated to implement in a real atmosphere. Therefore the methodical direction has the most significant development. In geodetic production, only one methodological technique is used. This is the determination of the refraction correction using the standard refraction coefficient. However, the accuracy of this method is insufficient. We are improving the angle refractometer based on the compensation method for refraction measurement. This way implements the two-wave dispersion method for angular refraction determination. The researchers faced several problems with the implementation of this method. Our refractometer scheme includes components that allow converting an information signal into an alternating electric current, amplifying it a billion times, effectively suppressing different types of interferences, and aligning different wavelength signals by the intensity and area of irradiation of photoreceivers. Furthermore, the developed scheme fully automates the process of registration and compensation of dispersion; as a result, the prospect of combining a refractometer with an electronic tacheometer into a single measuring complex opens up. In our opinion, this combination will make it possible to obtain values of angles, free from the influence of atmospheric refraction, with an accuracy close to the instrumental one.

Olga Vshivkova, Igor Kalugin
K-Fold Cross-Validation: An Effective Hyperparameter Tuning Technique in Machine Learning on GNSS Time Series for Movement Forecast

In deformation analysis, irregularly spaced data, extreme values, and anomalies in time series can lead to misleading simulations for forecast models, such as overfitting and underfitting. Therefore, K-fold cross-validation is one of the hyperparameter tuning techniques used in machine learning (ML) to deal with these problems. In this study, we use data from 22 permanent GNSS stations to predict the motion trajectory of the Earth’s crust. Lag functions and sampling techniques are applied to generate 924-time series samples. Time series standardization techniques are also performed to improve the quality of data. To test the efficiency of the K-fold cross-validation method, we investigate 26 mathematical models based on six ML algorithms. The optimal K values are selected through trial methods. Root mean squared error (RMSE) of validation and test is the basis for determining the overfitting and underfitting models. The investigations show that the optimal intervals of K-fold range from five to ten folds for the GNSS time series with many anomalies, jumps, and significant variations, from three to ten for stable time series. The sensitivity of cross-validation is more effective on the time series of the Up component than those of the North and East components. In addition, cross-validation can also detect effectively overfitting and underfitting for forecast models in motion of permanent GNSS stations.

Nhung Le, Benjamin Männel, Mihaela Jarema, Thach Thanh Luong, Luyen K. Bui, Hai Quoc Vy, Harald Schuh
Evaluation of the Accuracy of the Mosaic DEM Generated with Stereo Images of the Peruvian Satellite System (Perú)

The Peruvian satellite system provides stereo-capable images that allow users to generate digital elevation models. However, most DEMs generated are considered representative and do not have the positional control analysis determining the quality of the same serious limiting factor for their use in cartography. This paper describes the extraction of the Lima Dem Mosaic at 3 m of spatial resolution generated with tri-stereo and stereo images of the Pleiades, Spot, and PeruSAT satellites and 114 geodetic control points. The rational functions mathematical model was used to generate the MosaicoDem, choosing as the mesh size of the DEM a dimension of 3 × 3 m. To verify the final accuracy in the vertical, 74 checkpoints were used. For the analysis of the positional accuracy of the DEM, the National Standard for Spatial Data Accuracy (NSSDA) of the US Federal Geographic Data Committee was used. Finally, to determine the data normality, the Kolmogorov Smirnov test was made. The results show an RMSE of 2.68 and an accuracy in the vertical of 5.25 m. Furthermore, the analysis of the influence of the slope in the errors does not show significant variation.

Carmen Villon, Wilder Caballero, Justo Giron, Martin Talavera, Luis Calle
Radio Direction Finding System Applied to Identify Pre-seismic Signals in the Adriatic Sea

In this study, we present the application of a multiparameter analysis for the search of seismic precursor candidates, tested with a deterministic approach. The seismic sequence analyzed concerns the earthquakes that occurred on March 27, 2021, in the Adriatic Sea, characterized by seventeen earthquakes greater than Ml 2, occurring in less than two hours with the main shock of magnitude Mw 5.2. In the pre-seismic phase, with a time window of five days from the first earthquake, three types of signals have been detected in temporal sequence, which occur with decreasing times from the seismic event. The start of the monitoring is given by the emission of radon gas Rn-222, followed by the emission of radio anomalies within the frequency band of 3 Hz, and then by the direction of electromagnetic signals describing the future epicentral zone. Applying this method, in this case, resulted in a successful prediction regarding the time window and epicentral zone but not the magnitude.

Valentino Straser, Daniele Cataldi, Gabriele Cataldi
Out-of-Sequence Faulting Is Not an Exception but a Rule: Evidence from India-Eurasia Collisional Orogen

Out-of-sequence faults are observed in orogenic belts. These faults are located in the interior regions of the orogenic wedges. They are considered out-of-sequence in a dominant foreland propagating thrusting sequence. The cause of their formation remains controversial because the traditional consensus of mountain-building processes cannot fully explain their occurrences. Over the decades, two terms have emerged to explain the so-called anomalous behavior of these faults. The term “out-of-sequence thrusts” argues that thrusts are not following a sequence expected from a foreland propagating deformation sequence; faults that follow the line are called “in-sequence-thrusts”. Morely (Am Assoc Pet Geol Bull 70:12–25, 1986) argues against using these terms; instead, he suggests the usage of regressive thrusts. Our mapping in the interior region of the NW portions of the Himalayan orogenic system shows that active faults are widespread. The occurrence of earthquakes in the area supplements it. Examining the earthquake centroid moment tensor (CMT) events suggests that out-of-sequence faults are not only restricted to thrusting events revealed by the occurrence of active reverse, strike-slip, normal, and oblique faults. Therefore, our data support that out-of-sequence faulting is of common occurrence, which means that such faults would be expected during the life cycle of a typical orogenic belt. During orogenesis, deformation is mainly consumed in the frontal thrust system, which means the interior faults would be less active. Therefore, regressive faulting makes more sense than out-of-sequence faulting, which means such faulting is not an exception but a rule.

A. A. Shah, Navakanesh M. Batmanathan
Study of Seismic Precursory Nature of Soil Radon with a Network of Monitoring Stations in Eastern India

Radon concentration in soil, a well-known short-term precursor of an earthquake, was monitored for about five months in 2018, simultaneously at three monitoring stations in the eastern Himalayas and the Bakreswar-Tantloi geothermal region of east India. The eastern Himalayas is one of the world’s six most seismically active regions. In contrast, the geothermal area, although considered ‘non-seismic’, has experienced small to moderate earthquakes over the years. The recorded data shows that various physical and meteorological parameters influence the emission of radon gas from soil, resulting in complex nonlinear nonstationary radon time series. A nonlinear two-step technique consisting of empirical mode decomposition and Hilbert-Huang transform was applied to remove influences of periodic factors. However, as this method alone is inadequate to identify the effects of geophysical factors, the networking approach was adopted in conjunction. The study looked for precursors for earthquakes of magnitude 5.0 or above within 500 km epicentral distance from each monitoring station; however, for earthquakes of smaller and larger magnitudes, smaller and larger epicentral zones, respectively, were considered. Apart from several seismicity-induced anomalies found in the radon time series of all three stations, one anomaly was observed almost simultaneously from all three monitoring centres preceding an M 5.3 earthquake that occurred on 12 September 2018, in Kokrajhar, Assam. The epicentre of this earthquake was found to be in the common region monitored by the three centres.

Saheli Chowdhury, Chiranjib Barman, Muhammed Nurujjaman, Dipok Bora, Argha Deb
Destructive Intraplate Earthquakes in Arabia—The Archeoseismological Evidence

The Arabian Plate is surrounded by seismically highly active margins, while the plate interior is seemingly aseismic. To add unknown events to the historical catalog, new archeoseismological studies of four intraplate sites are presented here. We surveyed buildings seeking evidence of seismic damage and/or following reconstructions, assigned destruction intensity values, and dated destruction events based on building stratigraphy and historical sources. Qalhat in northern Oman is a ruined Medieval city. It is > 300 km from the closest plate boundary of the Makran subduction. An earthquake caused I = VII damage in 1494, from which it recovered. The next event, causing I = XI damage, occurred between 1570 and 1592 AD, yielding destruction. Julfar city near Ras al-Khaimah (United Arab Emirates), > 100 km from the Zagros collision zone, suffered I = VIII damage in the late fifteenth century. Palmyra (Syria) is > 180 km from the Dead Sea Fault. A preliminary survey identified evidence for earthquake(s) causing I = VII and more severe damage. Umm al-Jimal in northern Jordan is > 70 km from the Dead Sea Fault. I = VII damage occurred in the city during late Byzantine times, between 550 and 650 AD, from which it recovered. However, following I = IX damage at the end of the Umayyad period, it was abandoned. It is suggested that systematic archeoseismological studies can provide evidence for destructive earthquakes in Arabia, for which written documentation was lost. Promising sites are along the coasts of the Gulf of Oman, the Arabian (Persian) Gulf, the Zagros foreland in Iraq and Syria, eastern Jordan, the Red Sea in Saudi Arabia, and much of Yemen.

Miklós Kázmér, Mohammad Al-Tawalbeh, Krzysztof Gaidzik
Reassessment of the November 7, 2010 Earthquake Northwest of the Aswan High Dam, Egypt

On November 7, 2010, an earthquake of magnitude 4.6 ML hit the area between the High Dam and the old Aswan Dam, 4.5 km northwest of the High Dam. It occurred near the spillway fault (24.00 °N, 32.85 °E), which is believed to be the origin of this activity. This earthquake was felt in Aswan and the surrounding areas. Aswan local seismic network and Egyptian National Seismic Network (ENSN) were used to pinpoint the event’s venue. Extensive ground cracks were discovered in the epicentral region west of the spillway fault. Seismic activity in this region from 1982 to 2020 indicates almost no seismic activity before 1999. From November 1999 to July 2003, a few minor events occurred in conjunction with the seasonal rise in the lake water level, which exceeded 180 m in 1998, 1999, 2000, and 2001 and peaked at 181.6 m in 1999—this event’s total moment tensor decomposition revealed a non-double-couple variable. The fluid pore pressure from intrusion into pre-existing intersection faults by the lake can cause the non-dual pair segment. A microgravity survey was carried out in the epicentral zone. The outcome demonstrates a key feature of N-S trending anomalous activity. This function can be interpreted as a complex fault system that runs vertically to obliquely. This fault system’s amplitude is shallow in depth and has a high-density contrast. The leveling measurements showed subsidence along the spillway fault’s western side and uplift along the eastern side.

Abdelmonem Mohamed, Hamada Saadalla, Gaber Hassib, Haggag Mohamed, Nadia AbouAly
Seismic Assessment of Vertically Irregular RC Frame Buildings Designed Using Direct Displacement-Based Design Approach

In recent years, open-ground story (OGS) RC buildings have been famous in India due to the availability of high parking spaces. On the other hand, OGS buildings are among the most common forms of vertically irregular RC buildings, where irregularity lies at the ground level. This study evaluates the seismic response of OGS RC buildings under earthquake ground excitations. Direct displacement-based design (DDBD) approach is used in designing the case study of eight-storied OGS frame buildings. RC buildings are adopted in three different structural configurations, having the same plan area and height but with different plan-aspect ratios. The seismic evaluation is performed by nonlinear dynamic analysis under various earthquake records. The selected earthquake ground motion records are all far-field earthquakes having a hypo-central distance of more than 10 km. Therefore, the tremors are compatible with the design target response spectrum of Indian Standards. The seismic assessment uses maximum displacement and inter-story drift ratios from the nonlinear dynamic analysis. A life-safety damage state of 2% is considered the target performance objective per FEMA-356. The results indicate that OGS buildings designed by the DDBD approach can easily be implemented and successfully satisfy the target performance objectives.

Anurag Sharma, Rajesh Kumar Tripathi, Govardhan Bhat
Fingerprints of the Dark Universe in Geoscience

Dark matter (DM) dominates our universe, while its nature remains unknown. To unravel its composition is of fundamental importance for all physics. The solid Earth, with its atmosphere, could be the new target and detector of “invisible matter”. Any not well-understood dynamical behavior is of potential interest, e.g., the anomalous annual temperature excursions in the stratosphere and the global electron content of the Ionosphere (with its anomalous behavior around December-January known since 1937) also show planetary relationship, which is the ultimate signature for streaming DM involvement. Because this to happen is not expected within known physics, since a remote planetary tidal force is extremely feeble to cause any noticeable impact. Following this reasoning, here we present novel results combining the dynamical behavior of spatiotemporally occurring atmospheric activity with inner Earth activity like earthquakes. This finding should encourage geoscience to make the Earth the as-yet overlooked observatory for (streaming) DM, even parasitically, because Earth’s dynamic atmosphere and seismic activity are monitored continuously for other reasons. Of note, such an endeavor would be a natural extension of using the Earth to detect conventional cosmic rays. Exotic cosmic particles like anti quark nuggets, magnetic monopoles, and hidden-sector photons are among the most promising candidates. Other as-yet unpredicted DM constituents could make the surprise.

Konstantin Zioutas, Vassilis Anastassopoulos, Athanasios Argiriou, Giovanni Cantatore, Serkant Cetin, Antonios Gardikiotis, Jinyun Guo, Haris Haralambous, Dieter Hoffmann, Sebastian Hofmann, Marin Karuza, Abaz Kryemadhi, Marios Maroudas, Andreas Mastronikolis, Christina Oikonomou, Kaan Ozbozduman, Yannis Semertzidis
The 18th March, 2021 Bejaia (North-East Algeria) Earthquake Mw: 5.9

On March 18th, 2021, at 00h04mn (UTC), a moderate earthquake (Mw: 5.9) hit Bejaia city, located 200 km east of Algiers, the capital of Algeria. This event happened more precisely 17 km northwest of Cap Carbon inside the large bay of the city. This earthquake, the largest recorded offshore event since the May 21st, 2003 Boumerdes earthquake, triggered several aftershocks and caused damage to 2000 houses and social infrastructures, but no fatalities were reported. Onshore, the earthquake induced many rock falls along the rocky coastline. Offshore, this event also produced a small tsunami (a few cm) recorded by Spanish tide gages. In addition to the permanent Algerian seismic network, several portable stations were installed in the epicentral region to constrain the aftershock locations better. The waveform inversion of the main shock and the first day’s aftershock analysis allowed us to give the main preliminary characteristics of the event. This analysis revealed that the event occurred along an EW reverse southward dipping offshore fault in the western part of Bejaia Bay with a seismic moment of 8.70e + 17 Nm corresponding to Mw 5.9. The earthquake does not seem to be associated with the main NW–SE striking strike-slip fault, the so-called Babors transverse fault (BTF) recently identified (Boulahia et al., Pure and Applied Geophysics 178:1253–1279, 2021). This event belongs to the series of numerous earthquakes which affected the Lesser Kabylia block region from 2017 to 2021. It is typical of the African-Eurasian incipient subduction process along the northern Algerian margin. The study of this event is in progress and will allow us to better define the geometry of the fault and the rupture process. The occurrence of such offshore events, together with historical seismic events, highlights the necessity to re-evaluate the seismic risk for the City of Bejaia, where major seismic events could occur like the previous Boumerdes event of May 21st, 2003 (Mw: 6.8).

Abdelkarim Yelles-Chaouche, Chafik Aidi, Hamoud Beldjoudi, Adel Chami, Redouane Chimouni, Issam Abacha, Oualid Boulahia, Yahia Mohammedi, Abdelaziz Kherroubi, Athmane Belahouane
Site Response Mapping at Pulau Pinang, Malaysia Using the Horizontal-to-Vertical Spectral Ratio Technique and Multichannel Analysis of Surface Waves

Evaluation of the soil site response is vital for the mitigation and preparedness of strong ground shakings of earthquake type. Among several techniques available, both the horizontal-to-vertical spectral ratio (HVSR) and the multichannel analysis of surface waves (MASW) were adopted because of their feasibility and suitability for the study area. A dense population and several strategic hi-tech industries characterize the study area. The current work is motivated by the need to prepare a mitigation and preparedness plan for a future large earthquake. Although both techniques can be conducted separately to quantify the soil response, the present study adopted a joint analysis of both methods to fill the shortcomings of both. For instance, the HVSR technique faces a debate that peak amplitude does not represent the expected accurate amplification. This resulted from the discussion on the nature of the ambient seismic noise used for the HVSR analysis. To overcome this, the research adopted the HVSR and MASW survey conducted at 110 sites considered in this work. The aim is to use the 1-D transfer function deduced from MASW to build a model to obtain the amplification factor through regression analysis. This will end up with an equation to correct the amplification factor obtained from HVSR. The regression gave bad fitting when using the undamped 1-D transfer function. However, the fitting has significantly improved when using the damped 1-D transfer function. The model obtained applies to the Penang peninsula and may help with a more realistic seismic hazard assessment.

Amin Khalil, Mohd Nawawi, Geraldine Anukwu, Hesham Abdelhafiez
Kinematic and Elastic Modeling of Fault-Related-Folds: A Comparison Between El Asnam and the Sahel Active Structures

Active fault-related folds with surfacing, hidden, or blind thrust are tectonic structures capable of generating large-magnitude earthquakes (Mw > 6.5). We study active folds using geological and geomorphological field observations coupled with seismic parameters of moderate to large earthquakes of the central Tell Atlas (Algeria). Case studies are taken from the El Asnam fault-related fold responsible for the 1980 large earthquake (Mw 7.1) and the coastal Quaternary Sahel anticline with an active crustal structure tectonic geomorphology. Field investigations in Plio-Quaternary geology and tectonic geomorphology are conducted using high-resolution Pleiades correlated with the active tectonic features of each folded structure. Fault parameters are taken from the fault-related fold dimensions and geometry at the surface and depth using the seismicity distribution and focal mechanisms. El Asnam case study provides data on (i) coseismic surface folding and its relationships to the 1980 earthquake faulting at depth and (ii) coseismic rupture geometry and related seismogenic depth using the mainshock and aftershock distributions. The coastal Sahel active fold affects late Quaternary marine and alluvial terraces and may be related to a blind or hidden fault. The folding and faulting analysis compares the elastic modeling in isotropic homogeneous half-space (Okada, Bull Seismol Soc Am 82:1018–1040, 1992) with the kinematic modeling (Allmendinger, Tectonics 17(4):640–656, 1998). Modeling approaches suggest 1 ± 0.2 mm/year shortening across folds, and the comparative study of the fault rupture at depth and surface shows the seismogenic potential of active folds.

Souhila Bagdi-Issaad, Mustapha Meghraoui, Jugurtha Kariche, Ahmed Nedjari
Highlighted Active Tectonics Markers Along Fault-Propagation-Folds in the Tell Atlas (Algeria), Using High-Resolution Pleiades Images

High-resolution satellite Pleiades images produce accurate Digital Elevation Models for precise geomorphological and geological observations. DEMs of 1 m resolution are generated using the PCI Geomatica program to calculate morphometric parameters in relation to active tectonics. The valuable products help identify and characterize tectonic structures in earthquake-prone areas for a better seismic hazard assessment. The Tell Atlas of Northern Algeria was the site of large and destructive earthquakes due to a transpressive tectonic regime and convergence along the western Mediterranean’s Africa–Eurasia plate boundary. Here, we use a panchromatic and multispectral tri-stereo “Pleiades” acquired by ISIS-CNES from 1A and 1B optical satellites. They operate in a true constellation and orbit at 180° to each other. Our data covers large areas with 04 fault-related folds associated with past earthquakes (1922 Tenes Mw 6.2; 1980 El Asnam Mw 7.1; 1989 Sahel-Tipasa Mw 6.0, and 2003 Zemmouri Mw 6.8). The panchromatic product (0.5 m resolution) includes a black and white band. It covers the visible spectrum’s 0.47 and 0.83 μm wavelengths. Raw and processed images highlight geomorphic markers of late Pleistocene and Holocene tectonic movement determined from marine, lacustrine, and fluvial terraces distribution. Fault scarps traced along triangular facets of folded geological units characterize the seismic potential of tectonic structures with long-term cumulative surface deformation. The contribution of satellite Pleiades images seems to be significant in earthquake geology and, ultimately, in seismic hazard and risk evaluation.

Souhila Bagdi-Issaad, Mustapha Meghraoui

Numerical and Analytical Methods in Mining Sciences and Geomechanics

Frontmatter
Fractured Reservoirs: An Extensive Geomechanical Integrity Approach

There is no more challenging task for today’s oil and gas production companies than simulating the production behavior of naturally fractured reservoir fields. These reservoirs are highly prosperous at their early production stage, only to decline afterward. The previous behavior has raised awareness of the geomechanics role in controlling the deliverability of those reservoirs. This is not a straightforward rock mechanics problem to tackle as it requires dealing with two constituting continuums, matrix and fractures; they respond differently to solicitations. Hasdrubal is a naturally fractured reservoir field located offshore Tunisia. Recently, the area has manifested profound integrity and water coning issues. An integrity study was necessary to accurately determine the ever-changing stress settings and assimilate their impact on the production trend. Thus, former geomechanical investigations of the field were revisited to acquire a strong understanding of the reservoir and develop an appropriate three-dimensional geomechanical model (3D-GM) that incorporates the invasive impacts of faults/fractures on the mechanical and hydraulic behavior of the field. The 3D-GM was initially deployed to appraise the alteration of the governing stresses and strain setting induced by the reservoir depletion before generating a potential reactivation map of the faults at current and future conditions.

Kais Ben Abdallah, Salma Souissi, Essaib Hamdi
An Investigation of the Rock Creep and Its FE Modeling

The constant force method with stress compensation is a widely used technique in laboratory creep tests. But the method does not board well with the ideal creep loading definition. Hence, there is some discrepancy when using creep properties obtained from those tests. In the present paper, an attempt is made to study rock creep using three-dimensional Finite Element (FE) analysis. The simulation of the creep test does not yield a precise response due to the influence of many factors, namely, load condition and end-plate restraint. This FE model is developed to simulate rock creep and corresponding creep parameters with strain versus time curves are adopted from the literature. Furthermore, a visco-elastic model that would correct the creep curve is adopted and a back-analysis method is proposed. Obtained corrected creep curves from the experimental creep curves would help to better understand rock creep and quantify various influencing parameters and long-term performance of rock engineering structures.

Rajaguru Rajagopal, Vidya Bhushan Maji
Stability Analysis of Rock Slope Along National Road 43 (Northeast Algeria)

The national road 43 connecting Jijel to Bejaia (Northeast Algeria) runs along the Mediterranean Sea and crosses a volcano-sedimentary rock massif of more than 50 km. The road development of this ledge is constantly being considered for the needs of road traffic. However, several topographic and geotechnical constraints permanently threaten the rock cliffs overhanging the sea. Various land movements (landslides, rockfalls) occur during the multiple realizations of road works on the sections treated in this study. Before deciding on the state of stability or behavior of the Liassic rock mass in the study section (RN 43), we were interested in several sites divided into stations and in particular the station Aftis, part of the study region of national road 43 linking Jijel to Ziama (Northeast Algeria). We also want to recall that the fragile state of this massif has been detected by the records of discontinuities observed on site. All this disparity of discontinuity orientations has been recorded throughout the tectonic phases within the Brek unit and the Babors in general, whose tectonic compartmentalization was initiated in the Lias and remobilized during the Meso-Cenozoic. Slope mass rating and Continuous Slope Mass Rating are used for the evaluation of the assessment of slope stability. The stability analysis is also used in this study to determine a factor of safety value (Fs). The result indicates that Continuous Slope Mass better asses the slope stability from the stability calculation and field observations. Our works demonstrate that the rock slopes of station Aftis are classified as unstable rock slopes with a probability of falling from the wedges block (95.80%).

Chahra Yellas, Riad Benzaid
Effect of Compressive Strength on Blasted Rock Fragmentation in an Aggregate Quarry

This paper aims to study the effect of the strength of the rock mass and blast design parameters on the degree of blast fragmentation in the aggregate quarry Djebel Bouzegza C01 in Boumerdes, Algeria. Before the blast operation, it was conducted to obtain the strength value through the uniaxial compression strength (UCS) test of three blocks of bench blasting. After the blast, photographs of the muck piles fragments were taken to evaluate the fragment size using the image processing software Split-Desktop and compared them with the Kuz-Ram model results. Therefore, the mean fragment size X50 obtained by the Kuz-Ram model and Split-Desktop were linked to their respective UCS value, and the coefficient R50 was calculated as an error between the two methods. For improving the blasting, it was carried out by adjusting the design blast (burden and spacing) and the specific charge of the explosive using the empirical model of prediction Kuz-Ram. It is found that the strength of in-situ rock and the geometrical variables of design affect the distribution size fragmentation in a blast.

Khaoula Bedri, Djoudi Merabet, Mohamed Aguid Bachar Assed
The Importance of Joint Set Measurements for Slope Stability and Design Case Study: Ikpobia BUA Quarry, Okpella, Edo State, Nigeria

The kinematic analysis technique is largely used to assess the ability of rock slopes. Its objective is to identify the possible modes of slope failure by determining discontinuities’ properties. Kinematic analyses of planar discontinuity sets in three zones of a marble quarry in Okpella, Edo State, Nigeria, were carried out to illustrate the importance of kinematic analysis in assessing slope stability. Joint sets were measured, and their kinematic analysis was carried out using DIPS software. The results of the investigation showed the possibility of potential slope failures in the three zones. It was observed from the results that the most stable zone is zone 3, and the other two zones potentially are unstable and face the risk of failure. In zone 1, the most dominant failure mode is wedge sliding (50%). In zone 3, there is a small probability of occurring of flexural and direct toppling (16%). While in zone 5, the direct toppling mode of failure is critically possible (75%) in the left, middle, and right benches, with the possibility of wedge sliding in the left bench. These results show the importance of measuring discontinuity orientation for increasing stability in mines with slopes and by better design.

Ouadadi Senouci, Olugbenga Akindeji Okunlola
Performance of Hyperbolic Model Parameters for Non-cohesive Soil-Concrete Interface

The response of the stress–strain curve at the soil-concrete interface is nonlinear. The interface response is generally idealized in numerical modeling using a hyperbolic model. The hyperbolic interface model (IHM) is versatile and has been used by researchers for various soil-structure interaction applications. The parameters (modulus number ‘Kj’, exponent ‘n’, friction angle between soil and concrete contact ‘δ’, and failure ratio ‘Rf’) for this model have been evaluated using an interface shear test in the laboratory. The parameters ‘Kj’, ‘n’, and ‘Rf’ have evaluated from the transformed shear stress–shear displacement curve, whereas ‘δ’ has been assessed directly from normal and shear stress. These parameters mainly depend on particle size, moisture content, and soil density. The process of evaluation for these parameters is very tedious if the samples are in large numbers. Thus it is necessary to study the IHM parameters for variation in particle size, moisture content, and density so that the appropriate correlations have to be established to evaluate these parameters directly. In this investigation, the large box shear test has been carried out on concrete-non-cohesive soil (coarse, medium, and fine sand as well as fine gravel) interface. The test was conducted in dry and moist conditions. The performance of IHM parameters for various particle sizes, moisture content, and density has been studied. The generalized correlations have been established for every parameter based on particle size, moisture content, and density. These correlations can be directly used for the evaluation of model parameters.

Gaurav D. Dhadse, Gangadhar Ramtekkar, Govardhan Bhatt
Fines Generation and Its Impacts at Morupule Underground Coal Mine, Botswana

Fines generation is one of the common problems associated with coal mining, such as mine accidents, land subsidence, water contamination, and air pollution. Mining companies spend a lot of money annually to reduce and mitigate the impact of fines generation. A study was conducted to identify the causes of fines generation at Morupule Coal Mine and evaluate its economic and environmental impacts. Twelve coal samples of 20 kg were collected from each of the four operating mining sections and conveyor belts. They were tested for their mechanical and chemical properties. The results show that coal from section SM 3/1 is the most brittle, with a value of 31.25%, while the coal from section SM 4/5 is the least brittle, with a value of 15.5%. The fines generated vary from 3 to 13%. The transfer points account for the highest (up to 9%), while the fastest conveyor belt contributes about 8% of fines. The fines cause blockages at the tail ends of the conveyors, causing approximately a loss of 575 tons/shift. Targets are also not met at the wash plant due to more fines. In terms of air quality and health hazards, the environmental impact of fines generation is negligible as the mine employs strict dust control measures.

Saubi Onalethata, Suglo Raymond, Bheemalingeswara Konka
Metadaten
Titel
Recent Research on Geotechnical Engineering, Remote Sensing, Geophysics and Earthquake Seismology
herausgegeben von
Attila Çiner
Zeynal Abiddin Ergüler
Mourad Bezzeghoud
Mustafa Ustuner
Mehdi Eshagh
Hesham El-Askary
Arkoprovo Biswas
Luca Gasperini
Klaus-Günter Hinzen
Murat Karakus
Cesare Comina
Ali Karrech
Alina Polonia
Helder I. Chaminé
Copyright-Jahr
2024
Electronic ISBN
978-3-031-43218-7
Print ISBN
978-3-031-43217-0
DOI
https://doi.org/10.1007/978-3-031-43218-7