Building Knowledge for Geohazard Assessment and Management in the Caucasus and other Orogenic Regions

Practical cooperation in the framework of NATO’s Science for Peace and Security (SPS) Programme represents a unique opportunity to build networks among scientists and experts from NATO and partner nations. By supporting the development of joint collaborative activities, the Programme contributes to promoting scientific innovation, dialogue and knowledge-sharing, while delivering tangible results that contribute to tackling emerging security challenges in key areas, such as cyber defence, counter-terrorism, and security-related advanced technology. This chapter provides an overview of Georgia’s participation in SPS activities, outlining in particular the contribution of the Programmes’ activities to energy and environmental security in the country and the surrounding region.

We hereby provide an overview of four multi-year projects on geohazard assessment and mitigation, carried out under the umbrella of the North Atlantic Treaty Organization (NATO), with the involvement of more than 80 scientists coming from several countries, among which the US, Georgia, Italy, Russia, Azerbaijan. The projects have been aimed at enhancing the security of people and the safety of vital infrastructures as well as facilitating cooperation between scientists from NATO and non-NATO countries. The study areas are located in the Caucasus (Georgia), in Central Asia (Kyrgyzstan) and Northeast Asia (Kamchatka).

Our work clearly demonstrates how Earth Science can contribute to improving scientific collaboration among countries that are politically in tension; moreover, geoscience can play a key role in preventing situations that may escalate into conflicts. This paper showcases the main results of the NATO-funded projects, both in terms of their scientific relevance and their geopolitical importance.

In this paper, we describe the active kinematics of the Greater Caucasus (territories of Georgia, Azerbaijan and Russia) through an integrated analysis of seismological, geological-structural and GPS data. Alignments of crustal earthquake epicentres indicate that most seismic areas are located along the southern margin of the mountain belt and in its north-eastern sector, in correspondence of major, active WNW-ESE faults, parallel to the mountain range. Focal Mechanism Solutions (FMS) delineate dominant reverse fault kinematics in most sectors of the mountain belt, though swarms of strike-slip FMS indicate the presence of active transcurrent faulting, especially along the southeastern border of the Greater Caucasus. The mountain belt is characterized by dominant NNE-SSW-oriented P-axes. In the central-southern sector, in correspondence of the local collision between the Lesser and Greater Caucasus, P-axes are mainly NNW-SSE oriented. GPS data show dominant motions to the NNW, with rates increasing in eastward direction. All observations are consistent with a component of eastward escape of the central-eastern part of the Greater Caucasus.

A new, crustal-scale structural model aimed at illustrating the recent geometry of the western Greater Caucasus, has been built based on surface and subsurface data, in agreement with the theory of fault-related folds. The crustal-scale, structural cross-section shows that the western Greater Caucasus has a double vergence with a pro- and a retro-wedge actively propagating towards the Rioni foreland basins to the south and the Terek basin to the north. The retro-wedge and the Terek foreland basin developed on the upper plate, whereas the pro-wedge and the Rioni foreland basin developed on the lower, subducting plate. The formation of an antiformal stack in the axial zone of the western Greater Caucasus is related to reactivation of pre-existing normal faults during the orogeny. The main style of deformation within the pro-and retro-wedge is a series of fault-propagation and fault-bend folds, duplexes and structural wedges. Within the frontal part of the pro-and retro-wedge, a series of thrust-top basins developed.

The thrust front of the central Lesser Caucasus and southern part of the Greater Caucasus orogens is one of the key regions of an apparent convergence zone between two orogens. The formation of the complex structure of the Lesser Caucasus-Greater Caucasus convergence zone is governed by the northward and southward-directed thrusting. Here we show the structural style of deformation of a convergence zone between Lesser Caucasus retro-wedge and Greater Caucasus pro-wedge based on seismic reflection profiles. Seismic profiles reveal the transition between convergence and the initial collision zone within the study area. The frontal part of the Lesser Caucasus retro-wedge is represented by a shallow triangle zone and north-vergent structural wedge. The thrust front of Greater Caucasus pro-wedge is represented by south-vergent fault-related folds. Between the Lesser Caucasus and Greater Caucasus frontal parts, the undeformed Kura foreland basin is located. The structure of the Lesser Caucasus-Greater Caucasus initial collision zone is fairly complex. The orogens collision zone is represented by south-vergent imbricate thrusts. Under the triangle zone, there are two structural wedges. The frontal part of the eastern Achara-Trialeti fold-and-thrust belt exhibit structural variations along strike within the study area. Near the Lesser Caucasus-Greater Caucasus convergence zone is located Tbilisi city, where the north-and-south-vergent thrusts of this collision zone represent a significant seismic hazard.

The study of seismic activity triggered by transient stress changes associated with hydrocarbon reservoir exploitation and deep fluid injection is especially important, in a seismic risk perspective, in regions, where relevant natural seismicity is coupled with widespread and regionally distributed petroleum fields. Hydrocarbon occurrences in Italy derive from a variety of petroleum systems characterized by source/reservoirs distributed in age from Mesozoic to Quaternary. Several of them are located along and in the proximity of the Apennine Outer Thrust System which started to develop in Late Pliocene times and is still active, as well as seismogenic, along most of its extent (especially northern-central Italy and Sicily). Other occurrences are sited along the front of the more internal Pede-Apennine compressional belt, which was mainly active in Early Pliocene times. Still, a large percentage of hydrocarbon fields are observable within the Adriatic-Pelagian foreland, whereas a small number of fields, highly relevant in terms of oil and/or gas extraction, are sited within the intermountain Apennine active extensional domain. In this paper, after grouping the Italian oil and gas fields in stratigraphically and kinematically homogenous Hydrocarbon Field Assemblages (HFAs), we build a regional seismotectonic zonation of the HFAs, taking into account their surface and depth location with respect to the 3D boundary of regional seismogenic provinces. The provinces differ in kinematics (extensional, compressional, strike-slip) and in characterizing seismogenic thickness and depth, which may coincide or not with the depth range of the hydrocarbon recovery, as well as with the depth of fluid withdrawal and injection activities. The HFAs zonation is a new conceptual product intended as a regional-scale tool that contains base 3D geometric-kinematic information on the active and potentially seismogenic deformation in correspondence of all large Italian hydrocarbon fields. In case of a seismic sequence ongoing near an HFA (epicentral distance <~10 km), it could provide information on the Quaternary fault pattern and structural style characterizing the area, as well as on the associated crustal state of stress, as input constraints to the discussion on the likelihood of a direct or indirect link, controlled by tectonics, between the hypocentral area and the hydrocarbon field.

The Earthquake Model of the Middle East (EMME) project paved the road to a state-of-the-art seismic hazard assessment in the region, including Georgia as one of the key participants. After the EMME project, the Institute of Geophysics initiated the revision of the national seismic hazard model of Georgia, in light of the new findings of the EMME project, new harmonized datasets, fully aligned with the probabilistic framework promoted by the Global Earthquake Model (GEM). In this contribution, we present the main elements of a newly developed seismic hazard model for Georgia. We started with the updating of the regionally harmonized datasets (i.e. earthquake catalogues, area seismic sources) with focus on data collected in the recent years. The seismogenic source model consists of two key components: area sources and active faults combined with background seismicity. The main features of the seismo-tectonic domains in the Caucasus region were summarized into three seismogenic classes (i.e. shallow crust, volcanic sources and deep seismicity). Given this classification, a set of ground motion prediction models was selected for each tectonic region and used to quantify the inherent uncertainties of ground motion. The probabilistic seismic hazard was computed for the entire region using the OpenQuake engine; the results including mean and quantile hazard maps, hazard curves and hazard spectra. Comparisons with previous probabilistic seismic hazard maps, followed by a discussion and outlook, conclude the paper.

A sparse data set consisting of 33 local strong-motion recordings from earthquakes with magnitudes between 4.0 and 7.1 and distances between 8 and 190 km is used to develop an initial non-ergodic ground-motion model for the Georgia Republic for spectral acceleration at T = 0.2 s. The non-ergodic adjustments capture the local differences in the linear site effects and linear path effects. The non-ergodic GMMs have reduced aleatory variability along with shifts (increases or decreases) to the median ground motion for a given site/source pair. For sites in central Georgia, there is some local data to constrain the shift in the median ground motion from the base ergodic GMM. For sites far from the available local ground-motion data, such as the Enguri dam site, there is larger epistemic uncertainty in the shifts to median. In this case, the reduced aleatory variability will be offset by the larger epistemic uncertainty. Although there is large uncertainty, the advantage of using the non-ergodic approach in regions with sparse local ground-motion data is that the large epistemic uncertainty range is properly quantified and it shows the potential change to the hazard that can be expected as local ground-motion data are collected.

The 271-m-high Enguri arch dam, still one of the highest of this kind in operation in the world, was built in the canyon of the Enguri river (western Georgia) in the 1970s. It is located in a zone of high seismic hazard and is close to the Ingirishi strike-slip active fault. The strong seismic activity, as well as the great number of people living downstream of the dam, make this facility a potential source of a major catastrophe in Georgia. Thus, the Enguri Dam, with its 1 billion cubic meters water reservoir, should be under permanent monitoring. At the same time, this area is an amazing natural laboratory, where researchers can investigate both tectonic and geotechnical issues and the effects of load-unload processes at the artificial reservoir, i.e. the reaction to a controllable loading of the Earth crust. This is an important scientific topic, connected with the fundamental problem of reservoir-induced earthquakes as well as with environmental geotechnical problems, related to the security of major dams in general. The complexity analysis methods applied to time series of the fault strain monitoring data enables discriminating seismic events derived by the human activities and background seismicity.

Such complexity analysis provides a new approach – Reservoir Synchronized Induced Seismicity, or RSIS – for a quantitative assessment of reservoir water level load on the (synchronized/ordered) temporal pattern of local seismicity. Besides, analysis of complexity in the fault strain monitoring data can provide also some early warning methods for signaling dangerous deviations of fault strains and dam tilts temporal behavior from the stable (background) pattern.

The present work provides an assessment of the seismic hazard across the southern slope of the Greater Caucasus (territory of Azerbaijan). The parameters that have been taken into account include the moment magnitude, seismic energy, peak ground acceleration and site effects. The analysis output is expressed as the spatial distribution of peak ground acceleration (PGA) assessed at the maximum magnitude. The earthquake catalogue from the Republican Center of Seismological Survey (RCSS) at the Azerbaijan National Academy of Sciences (ANAS) was employed in order to perform the research. From the results of the probabilistic analysis, an earthquake with maximum M_W 7.9, is estimated for the central area, corresponding to the worst-case seismic scenario for the region. This is predicted to be the strongest possible earthquake, which can be generated within a collision zone along the Main Caucasus Thrust (MCT) and the West Caspian Fault (WCF). Considering the parameters of two target (scenario) earthquakes, based on the deterministic hazard assessment, the highest PGA values are distributed in the north-western part of the study area: 95–110 Gal (0.95–1.10 m/s²). This may have a significant impact, especially in terms of the safety of critical facilities in those areas.

Our work provides as review of Quaternary volcanic activity in the Greater Caucasus. In particular, we have focused our attention on the Elbrus (northern slope of the main range of the Greater Caucasus), Kazbek (central sector of the Greater Caucasus) and Keli (southern slope of the main range of the Greater Caucasus) volcanoes. After conducting detailed isotope-geochronological, geological and petrological-mineralogical studies regarding the above volcanic centres, we have been able to document multiple phases of volcanic activity: i) five phases have been defined for the Elbrus volcanic centre: I – 950-900 ka (andesite-basalts, trachyandesites and dacites), II – 800-700 ka (ignimbrites, rhyodacites, dacites and andesites), III – 225-170 ka (dacites), IV – 110-70 ka (dacites) and V phase – less than 35 ka (dacites); ii) four phases have been defined for the Kazbek centre: I – 460-380 ka (basaltic andesites and andesites), II – 310-200 ka (latest phase – andesites and dacites, earliest phase – basaltic trachyandesites, basaltic andesites, and dacites), III – 130-90 ka (latest phase – dacites, earliest phase – andesites and trachyandesites), IV – less than 50 ka (andesites and dacites); iii) for the Keli centre, three phases have been defined: I – 245-170 ka (dacites, rhyolites and andesite-dacites), II – 135-70 ka (earliest phase – dacites and rhyolites, latest phase – dacites, rhyolites, andesites and trachyandesites), III – less than 30 ka (dacites and andesites). Owing to the Holocene age of the latest phases of volcanic activity, these volcanic centres ought to be regarded as potentially active (dormant).

The purpose of the present work is to integrate previous research focused on the Abuli Samsari Volcanic Ridge, situated in the Javakheti Highland, Georgia. Through a synergic approach, consisting in the collection and analysis of field and satellite data, combined with the results of previously published research, we have been able to define the overall structure of the volcanic ridge, which, on its northern sector, is cut across by two parallel pipelines, carrying oil and gas from the Caspian Sea to the western countries. Despite the likelihood of seismic or volcanic events in the area, geohazard assessment had never been adequately performed for this section of the pipelines’ route across Southern Georgia. The most relevant outcomes of our effort, aimed at filling this critical gap, consist in: the identification and mapping of eruptive centers and tectonic lineaments; the reconstruction of magma pathways; the definition of the expected moment magnitude for possible earthquakes; the assessment of orientation of the maximum horizontal stress from the Late Miocene to the present day. We have used these results to evaluate the current seismic and volcanic hazards affecting the Abuli Samsari Volcanic Ridge, which may have major impacts on the security of the pipelines. The calculated, about N-S directed maximum horizontal stress may play a key role in volcanic reactivation, which might occur in the form of fissure eruptions and the formation of new vents and monogenetic as well as composite volcanoes. As the track of the pipelines lies just north of the younger volcanic edifice in the ridge we suggest that these lifelines could be severely affected by possible future volcanic eruptions, which might bring about a major interruption in oil delivery from the Caspian Sea towards the west.

Geological hazard posed by landslides, debris flows, rock avalanches and mudflows has always been and still represents a major threat for communities all over the world, causing extensive damage and often times the destruction of infrastructures and facilities. Over the last decades, the protection of the population from geohazards and the safe operation of infrastructures have become a significant priority for most countries in the world. Geological-related, adverse phenomena are more frequent in mountainous countries with high rainfall amounts and complicated geological settings. The above-mentioned geological hazards can also be favoured by climate change, earthquakes, as well as by pervasive human activities. Georgia belongs to one of the most complicated regions among the world’s mountainous countries: thousands of settlements, buildings, roads, oil and gas pipelines, high-voltage power lines are prone to geohazards, that can trigger disasters and lead to widespread losses of life and property. Consequently, geohazard assessment is an important step towards the management and mitigation of adverse, natural events. In the present work, we introduce a set of new hazard maps for geological hazard assessment, compiled by employing methods applied at the national level, with a particular focus on landslides and mudflows.

Landslides are the most common natural hazard in mountainous terrains and have a high potential to disrupt human activities and damage infrastructure when they occur in populated areas. The study area encompasses a portion of the Enguri Hydroelectric Dam (and reservoir), along with the steep, clay-rich slopes directly to the east of the reservoir. A large landslide in this area would have far-reaching negative consequences, as the Enguri Hydroelectric facility provides 50% of domestic energy production and serves as an anchor for socio-economic stability in the region. In order to reduce the risks associated with these slope failures, it is essential to improve our ability to forecast future landslides and determine which slope areas should be targeted for mitigation practices. This study will view the significance of input Digital Elevation Model (DEM) spatial resolution (30 m vs. 12 m) within a physics-based numerical model for regional slope stability analysis. Unlike the previous researches that have viewed the significance of input DEM spatial resolution within statistical slope stability models, we found that there is considerable improvement in the quality of output landslide susceptibility maps when utilizing DEMs with a higher spatial resolution. At 12 m spatial resolution, there is more distinct delineation of the reservoir boundary adjacent to the base of the hazardous slope. More importantly, the trials utilizing the 12 m DEM accounted for 0.22 km² of the new slope area that is considered “unstable” (FS < 1.25). These important details were completely missed at a spatial resolution of 30 m. The findings from this study highlight the advantages of utilizing high spatial resolution DEMs when using a physics-based numerical model for a regional slope stability analysis. Landslide susceptibility maps with higher spatial resolution reveal important slope details that could drastically improve the efficiency of landslide mitigation practices, and aid in the forecasting of potentially catastrophic slope failures.

During a 2-year period, we monitored deformation taking place within the Khoko landslide by means of high-resolution techniques. The mass movement is found on the eastern slope of the Enguri artificial water reservoir. A network of 20 benchmarks was established along the Mestia-Zugdidi road, at the head scarp of the landslide zone, for a total length of 1.8 km. Measurement campaigns were carried out during three different periods, from May 2016 until June 2018. We estimated the displacement velocity and vectors and provided end users with a GIS-based platform for immediate use of the collected data. The whole upper part of the studied slope is affected by continuous deformation with a quite constant displacement rate. During the observation period, maximum average velocity of net displacement amounted to as much as 0.44 mm/day (first period of observation), with an overall average velocity of 0.12 mm/day (entire period of observation). The whole set of benchmarks moved to the west, indicating a coherent displacement of the whole upper landslide area. We suggest that critical rates of displacement were not observed during this period. Anyway, we recommend continuing observations of slope movements using the current geodetic stations, in order to detect any possible alarming changes in deformation rates.

For the last one and a half-century, the Black Sea region of Georgia has been affected by the impact of adverse phenomena, which are the result of the violation of the balance of natural processes along the coastline due to human-induced interventions.

The first of such actions was the building of seaports in Poti and Batumi, during the second half of the nineteenth century. Along the seacoast, dozens of kilometres of shorelines suffered from drastic interference in the deposition balance. In the subsequent decades, because of the withdrawal of abundant material from the beaches and riverbeds, uncontrolled processes of intense erosion along the coast developed for hundreds of kilometres.

The construction of dams in the River Chorokhi basin, since the 1990s, had an extremely negative impact on the stability of the southern section of the Black Sea coast. Because of this, the deposition of material along the coast by the River Chorokhi has almost stopped. A similar process has taken place at the mouth of the River Enguri as well.

It is worth highlighting that it is very likely that an uncontrolled pattern of interference in coastal processes will go on in the future. Therefore, the environmental processes going on along the Black Sea coast need to be further analysed with a systemic approach.

Budget limitations require an optimal allocation of resources devoted to seismic risk reduction. In order to allow local Authorities to operate public interventions to strengthen more exposed structures, increase population preparedness and improve emergency planning, a detailed knowledge of seismic hazard at the scale of a municipality (or of the minimal administrative structure in charge for prevention activities) is mandatory. To this purpose, a gap must be filled between seismic hazard assessment at regional scale and seismic response study at the scale of a single building, which is typical anti seismic engineering practice. Seismic Microzonation operates at this intermediate scale, focusing on heterogeneities in the seismic ground motion expected at the scale of a settlement (village or town) as an effect of local subsoil and morphological conditions. Being extensive in nature, its sustainability requires the development of specific methodologies, characterized by cost-effectiveness and, at the same time, able to provide reliable and useful outcomes. In this paper, the seismic microzonation strategy developed in Italy and applied in the last 10 years is briefly outlined. Sharing this experience with other countries prone to damaging earthquakes like Italy, may be of main importance to develop a common strategy to cope with future earthquakes.

Seismic hazard and risk assessment is a crucial issue for Georgia, a country located in the Caucasus, which is one of the most seismically active regions in Alpine-Himalayan collision belt. It has long been known that subsoil conditions may have a significant influence on the expression of earthquake motions at the surface, modifying both amplitude as well as the frequency content and duration of the seismic ground motion. In this regard, seismic microzonation studies aimed at identifying and mapping zones, in a given area, characterized by homogeneous seismic behavior, represent a worldwide-accepted tool for the mitigation of seismic risk. In this paper, we provide the preliminary results of the first site effects assessment performed in the urban area of Mtskheta (Georgia). Our main outcomes consist in: (i) a geological map focused on the study area; (ii) a distribution map of resonance frequencies (f₀ and f₁); (iii) an estimation of the average shear-wave velocity of the upper 30 m (V_S,30) and (iv) the amplification factors from standard acceleration response spectra according to the EC8 classification. The results obtained will represent a first step toward reducing seismic risk in Georgia and providing a knowledge base of local seismic hazard, useful for effective seismic risk mitigation strategies.

Rheological properties of soils influence the surface response of strata to seismic ground motion. This paper presents modelling of site amplification in the South Ukrainian nuclear power plant. The territory of the South Ukrainian nuclear power plant was divided into 3 zones according to the results of seismic microzonation. For each zone, the resulting frequency response and a set of design accelerograms were separately calculated. The effects of the rheological properties of the soil on site amplification and resonance frequency are analyzed for each zone. In the conditions of the site of the South Ukrainian nuclear power plant, the roof of the bedrock changes quite sharply. This leads to a shift of the resonance maxima in a wide range of frequencies. The study of the variability of the parameters of ground motion during earthquakes depending on the rheological properties of the rocks and the structure of the surface part of the section of the site is an essential element in earthquake-resistant design, reconstruction and extension of the life of buildings and structures.

The direct method of mechanics is utilized in studying the passing and reflecting of SH-wave while it propagates through the finite number of ground layers with differing thicknesses and rheological properties. The mechanical properties of the ground layers are described by the Hookean and standard rheological models. The explicit formulas for evaluation of the wave number and attenuation of the harmonic SH-wave are obtained. The wave attenuation is studied by two variants – by the spatial coordinate and in time. The obtained formulas can be treated as some continuation of the classical works of Prof. Savarensky (Russia) in the area of elastic seismic waves and Prof. Stepanishen (USA) in the area of viscoelastic seismic waves.

In the present work we applied the use of the UAV-based Structure from Motion technique (SfM) to geological and geohazard studies, with emphasis placed on active tectonics and volcano-tectonics cases. Our aim is to obtain high-resolution orthomosaics and Digital Surface Models (DSMs) in two study areas: the Theistareykir Fissure Swarm within the Northern Volcanic Zone (NVZ) of Iceland and the active Khoko landslide, Enguri reservoir, in the Greater Caucasus, Georgia. The first is affected by seismic and volcanic hazard, the second by landslide and hydrogeological hazard. Regarding the NVZ, by analysing the resulting Orthomosaics and DSMs we collected a total of 453 quantitative measurements of the amount of opening and opening direction of Holocene extension fractures and 36 measurements of the height of fault scarps. These data allowed us to assess an overall spreading direction of N106.4° during Holocene times within the studied rift zone, which has been compared with geodetic motion vectors, and a stretching ratio of 1.013–1.017 for 8–10 ka old lava units. We conclude that deformation in the area is related to both dyke intrusions and extensional tectonics. In the Greater Caucasus, we applied the method to identify the main geomorphological features related to the Khoko landslide and to measure the scarp height of the principal slip surfaces, in order to improve geomorphological knowledge of the landslide, and contribute to the assessment of the hydrogeological hazard of the area. At a general level, our results suggest that the use of UAV-based SfM is a convenient and efficient way to collect plenty of data aimed at better assessing geohazards in areas prone to catastrophic natural phenomena like earthquakes, volcanic eruptions and landslides.

The several geohazards, the costs for supporting personnel for long periods at potential mass movement sites, the growing number of exposed vulnerable objects and the limited resources of developing countries, the most affected by natural disasters, call for the development of cost-effective and at the same time, accurate, automatic monitoring/early warning telemetric systems.

We have developed the operating prototype of an original, cost-effective multi-sensor telemetric monitoring/early warning system with autonomous power source, aimed at forecasting the initiation of landslides/mudflows and sending alarms as far as 15–20 km by radio signals, or to a longer distances – by Internet or Mobile nets. Humidity, tilt and acceleration sensors, using modern high-tech elements (modified MEMS sensors and processing-diagnostic-remote transmitting ARDUINO blocks), are proposed. This ensures the cost-effectiveness of the system. The performance of our sensors has been compared with standard devices. Moreover, our system has been tested in laboratory conditions for defining optimal sensitivity, frequency and amplitude ranges. The EWS system, based on measurements of differential humidity, tilt and acceleration signals, was installed in October 2018 within the Gldani landslide (Tbilisi, Georgia). The EWS detected significant anomalies during and after the landslide event of 25 January 2019, as well as during intensive rainfall on 18 July 2019, which was not followed by significant landslide displacement.

The map of areas/objects affected by risk has been compiled for Georgia, in which the locations of dams, pipelines, roads, and high density of population are superimposed on a landslide hazard susceptibility map. This allows for the identification of areas, where the installation of EWS systems is especially recommended.

There are several ways to monitor the evolution of a mass movement in mountainous areas, such as a landslide: from inclinometers, helpful in measuring deep deformation, to piezometers, for determining water level within the unstable mass, to electronic and manual extensometers, suitable for assessing local deformation. Here, we document the results of an extensometer-based campaign of measurements carried out in Georgia from 2016 to 2019, at the giant Khoko landslide, located on the southern slope of the Greater Caucasus. The campaign was conducted in the framework of a NATO-funded project, aimed at identifying geohazards affecting the Enguri artificial reservoir and the related hydroelectrical plant. Our results, which are meant to be integrated by the more accurate GPS-measurements performed during the NATO-supported project, indicate that the Khoko landslide is indeed active, and its displacements appear to be controlled by variations in hydraulic load, in turn induced by lake oscillations and, although to a minor extent, by rainfall.

This manuscript presents an ad-hoc methodology for the assessment of the vulnerability of buildings to be applied in Georgia where such assessment is included in the management risk approach designed to work at the national level.

The risk management approach is based on the determination of several factors: specifically, it considers the severity and probability of occurrence of adverse events, the multiplicity and complexity of their impacts (anthropological, economic, environmental, political and social), and the determination of physical and social vulnerability. The physical vulnerability assessment of buildings is here generally defined against all events that produce mechanical effects on buildings, with special focus on natural hazards.