Landslide Science and Practice

Eleven rockslide dams exist in Møre og Romsdal county in Norway. Geological evidences indicate that more of such dams existed during the Holocene. Eight of those dams formed in prehistoric times, while two rockslide dams formed in historical time. One of the rockslide dams failed partially at the beginning of the Holocene eroding 45,000 m

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from the dam, however the remaining dam is stable and it is used for hydropower generation. Present hazard of rockslide dams is represented by the Mannen unstable rockslope. This site has a volume of 15–25 × 10

6

m

3

and is moving up to >4.5 cm/year on measurement points. A failure of the slope would dam the Rauma valley and few farms would be flooded upriver. However, due to the large discharge of the river the dam would only prevail a short time and dam failure is likely to cause inundation downstream. Here we present a probability analysis for this scenario.

The origin of mountains lakes’ dams is the source of much discussion among researchers. The most common interpretation is that gravitational phenomena on valley slopes are the primary source of such dams. Moreover, the biggest dams are interpreted as seismically triggered events, resulting in estimates of very high past seismicity rates for areas where such dams are located. Nevertheless, many big mountain river dams have the glacial origin, although the shape of such dams are the same like gravitational phenomena.

In Three Gorges area of China, the biggest dam in the world was constructed from 1994 to 2008. During the reservoir operation up to now, many landslides occurred. In this report, research results on Qianjiangping landslide, which was triggered by an initial impoundment in 2003 and moved for long distance with high velocity, and Shuping landslide, which was reactivated by the initial impoundment and moved slowly until present are presented. It is found that the slope structure controlled the influences of the water level variation. For slopes with dip-structure, large deformation may occur during water level rising; while for existing landslides with near circular sliding surface, the reactivation becomes active during water level decreasing, and the landslide deformation rate is proportional to the water level decreasing rate.

This paper presents an overview of seismic and mass movement hazards affecting major Hydropower-plants (HPP) and ongoing dam projects in the mountain regions of Central Asia. HPP cascades are located along the Naryn River in the Kyrgyz Republic and the Vakhsh-Surkhob valley fault zone in Tajikistan. The latter region hosting the presently and future tallest man-made dams of the world is very prone to earthquakes and various types of slope instabilities. The Naryn Valley hosting several dam sites is marked by the presence of ancient rockslides and a dense network of seismically active faults. In December 2009, Kyrgyz, Russian, Slovak and Belgian teams have monitored seismic ground motions and displacements induced by the blasting of a slope on the Kambarata 2 site producing a 35 m–high blockage on the Naryn River. This work is part of a NATO Science for Peace and Security project on landslide dam hazards in the Tien Shan.

The case study of the rockslide in the reservoir of 207-m high Fernando Hiriart Arch Dam (Mexico) is discussed. The problem required the stability analysis of this rock mass with the evaluation of its volume to estimate the consequences if the rock mass would fall into the reservoir. Evidently the sliding started when the water in the reservoir reached a certain level. The main problem of the analysis was the lack of information about the position and shape of the sliding surface and the shear strength of rock mass. The position and the shape of the sliding surface were predetermined on the basis of some premises, and the consequent numerical analysis allowed determining the shear strength of rock mass. On the basis of the results obtained it was concluded that with the normal water level the rock mass must be stable.

Gravitational mass movements on steep slopes (rockslides, landslides, rock falls) resulting from strong earthquakes could initiate multi-stage (synergistic) geohazards providing threat to large hydraulic facilities in the mountainous areas. The powerful explosion was performed to create blast-fill dam of the Kambarata-2 hydraulic power plant (KHPP-2) on the Naryn River upstream from the Toktogul reservoir (Kyrgyzstan). Its impact on the potentially unstable slopes at the construction site and its vicinities was studied. It would help to assess long-term slopes’ stability and to develop measures that have to be undertaken to prevent large-scale slope failures at the construction site and reservoir area and their negative consequences. In this work, we present the landslide risk evaluation of the Kambarata-2 hydraulic scheme performed within the frames of the NATO SFP LADATSHA Project.

New Zealand’s Young River was dammed on 29 August 2007 by 11 million m

3

of debris at 44° 08′ 44.6″S, 169° 06′ 46.0″E. The fractured biotite-schist debris travelled up to 1.8 km to form a 74-m high dam. Water flowed from the new 2.5 km-long, 23 million m

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lake after 5 weeks. The slope on the dam face is about 10°. The mean surface particle size is about 1 m (uniformity coefficient, 8). Lake level and rainfall at the dam have been monitored since 10th October 2007. There have been many high flows since then; the largest, 3.4 m deep at the outlet. The outlet had lowered 0.7 ± 0.2 m by January 2011; the channel mostly widened but locally aggraded and degraded as boulders < 1 m across moved. Larger boulders appear stable. Outlet lowering is attributed to 3 outlet flow depths > 2.1 m. The rainfall which put 3.4 m water depth through the outlet had an annual exceedence probability of 0.1 a

−1

. We estimate the expected (most probable) longevity of the lake as twice the current age, but recognise that this probabilistic estimate will eventually be 2x too large.

A protruding part of rock mass No. 65 was considered to be potentially unstable according to calculations of waterside slopes stability of Irganayskaya HPP reservoir. The assessment of mass residual displacements after a strong seismic impact has been made to define if there is a necessity of carrying out work to improve the stability of rock mass. Three nonlinear dynamic models of the rock mass have been developed to assess residual shears of rock. The influence of input parameters on the results of calculations has been studied. A 3D model in linear definition was calibrated by the results of seismometer observations over mass quakes. The received values of maximum residual displacements in the rock mass after a seismic impact made it possible to define a hazard to head front structures of Irganayskaya HPP from rock mass No. 65 that is connected with a danger of the wave appeared during rock sliding into the reservoir.

Evidence of former landslide-dammed lakes exists in several places of the Central Asian mountains, both from historic and prehistoric times. Geomorphic records help to understand recent processes: large landslides repeatedly dam lakes which then threaten the population downstream. Even though most dam failures occur in the first few months after formation, lakes may also drain suddenly at later stages. Two case studies from Northern Pakistan are employed to exemplify the involved phenomena regarding dam formation, outburst mechanisms and options for hazard mitigation.

The paper presents the numerical inverse analysis of a well-documented slow-moving landslide in Southern Italy which has been active in the 70s along the banks of an artificial reservoir servicing a hydro-electric power plant. A numerical procedure was adopted to predict movements of active landslides along pre-existing slip surfaces related to changes in the groundwater regime of the affected slope. The analysis was used to: (1) evaluate the absolute and relative importance, for the observed kinematic behaviour of the phenomenon, of the two triggering factors of the landslide: rainfall and changes of the reservoir’s level, (2) assess the effectiveness of different mitigation strategies on the basis of numerical predictions based on the calibrated model of the phenomenon.

Geology and landslide risk investigations are very important segments for the environmental impact assessment (EIA) study for any development project. Present study is focused to conduct the geology and landslide risks investigations for some of the mini hydropower projects in central highlands of Sri Lanka. The evaluation of general aspects of in-situ ground stability of the proposed location of the weir site, fore bay tank, penstock line and the power house have been investigated. The proposed locations to construct mini hydropower projects where moderate level of geological hazards and landslide risk exists can be recommended only with the applications of location specific guidelines and precautionary measures for the prevention of future geologic hazards and landslide risk. It is advised to adhere to some recommendations for the sound construction and operation of the proposed mini hydropower projects.

A first inventory of landslides responsible for river damming in Campania region (Italy) is here presented. Based upon archival research, cartography analysis, air-photo interpretation and field survey, thirty-six landslide dams have been recognized, along with four dams related to mixed fans. The inventoried cases have been classified according to the existing schemes; however, considering the peculiar features of the case studies, some new dam types have been introduced. Finally, a basic statistical analysis has been carried out, which revealed a good correlation among some environmental and geomorphometric variables.

High Rogun dam with overyear storage reservoir is under construction in the middle reaches of the Kyzylsuu-Surkhob-Vakhsh River basin in Tajikistan. Most of its catchment area slightly exceeding 30,000 km

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belongs to high mountains of Northern Pamirs and Southern Tien Shan and is subjected to glaciation and large-scale slope instabilities. Special studies have been performed to investigate if high blockages could originate upstream, what flood could result if they would fail catastrophically and to estimate effect of such phenomena on the reservoir and dam safety.

In the present work the 1963 Vajont landslide has been back-analyzed in detail to examine the influence of performed reservoir operations on the Mt. Toc slope stability. Coupled-seepage stability analyses show that the main trigger of the Vajont rockslide was the reservoir-induced water table which formed as a consequence of rapid seepage inflow. The permeability of the shear zone material occurring at the base of the Vajont rockslide is evaluated at 5·10

−4

m/s and back-calculated values of the friction angles Φ range from 17.5° to 27.0°. Considering mountain reservoirs, slope failures can occur during both filling and drawdown phases. In the Vajont case, due to highly permeable materials of the shear zone, the slope stability decreased during filling and increased during drawdown. Another time-dependent phenomenon of mechanical nature (progressive failure) has to be considered to understand the final slope behaviour related to the last drawdown.

On 11 April 2010 at 7:40 icefall and rockfall from the Hualcán Mt. caused flood on the Chucchún River, right tributary of the Santa River, near the city of Carhuaz, department of Ancash. Direct damage comprises of aesthetical or functional damage to several residential houses located close to the river bad, loss of livestock and damage to the drinking water treatment plan. Geomorphologic mapping along the watercourse identified areas with prevailing type of fluvial processes. Detailed cross sections of the stream and adjacent valley slopes were constructed using laser range finder. Special attention was paid to identify flood sediments at each cross section. These data along with topography were used to model the flood in 1D HEC-RAS model.

The Vajont landslide (NE Italy) occurred on the 9th October 1963, when approximately 270 million m

3

of rock slid down into the existing reservoir at 20–30m/s. The movement involved limestones and marls of the Fonzaso and Socchér Formations and occurred along a chair-like sliding plane. The landslide has been object of numerous studies but a comprehensive explanation of its triggering and dynamics remains elusive. Here we report the results of new structural and geomechanical data from conventional mapping on 88 field stations within and outside the landslide. Each station includes joints orientation, spacing, persistence and roughness, Geological Strength Index and Schmidt Hammer tests. The characterization of the landslide deposit was completed by the description of seven boreholes drilled by RODIO Company in 1965 down to the sliding surface. Representative rock samples were collected for laboratory measurements of the unconfined compressive strength, Young modulus and Poisson’s ratio. The new data represent an important tool to reconstruct a detailed 3D geological and geomechanical model of the landslide.

The impact of deep-sated landslides on reservoirs and river network has a long history within Vrancea Seismic Region. During the last 100 years, tens of such landslide cases were noted, blocking valleys and forming temporary and permanent lakes. Also, the reservoirs built for complex purposes are affected by deep-seated landslides, causing major disturbances in their activity, especially due to an accelerated silting process. Several case-studies were considered, among which Siriu landslide (250,000 m

2

, more than 2 mill.m

3

; blocked Siriu reservoir) and Zăbala landslide (1,900 m long; blocked Zăbala River). The study emphasize the role of earthquakes, long-lasting autumn rains and spring showers overlapping snowmelt in preparing and triggering such phenomena and also the role of reservoir level variations, as a result of inflow-outflow variability. The study represents an important step in understanding the behaviour of old, peri-glacial landslide reactivations and also a progress towards a better hazard assessment.

This study presents the detailed reconstruction of the entire structure of the oldest Vajont rockslide (270–300 million of m

3

) for the first time, describing the complex geometry and the characteristic superimposition of distinct rigid blocks on a very thick shear zone (40–50 m thick) made up of a chaotic assemblage of rock blocks, limestone angular gravel and high plasticity clays. Typical back-calculated values of the friction angle Φ

m

, obtained for the 1963 Vajont slide, ranged essentially from 17° to 27° but these are mean values referring to the entire slip surface and can differ considerably from the true shear strength properties of the materials effectively involved in the failure. This explains the difference between the friction angles measured by means of different shear tests on various Vajont clay samples (Φ

c

= 6–15°, prevailingly) and the typical back-calculated mean values. The recognition of the bottom shear zone is decisive both for the geotechnical and the hydrogeological modelling of the huge Vajont landslide (Oct. 9, 1963).

On 4 December 2007, a 3 Mm

3

debris avalanche entered Chehalis Lake, British Columbia, Canada. The resulting tsunami caused extensive shoreline damage as far away as the outlet (7.5 km) and far down lower Chehalis River (>15 km). We documented impacts of the tsunami through a multifaceted investigation that included field surveys and collection and analysis of SONAR data, LiDAR data and high-resolution orthophotographs. Geomorphic impacts included a wide range of erosional and depositional features, many of which provide information on wave energy, direction, run-up and inundation along much of the lakeshore. Our characterization of the geomorphic impacts of the Chehalis Lake event advances understanding of landslide-generated tsunami in several ways: it aids identification of events elsewhere by providing insight into their geomorphic signature; it provides an opportunity to verify hydrodynamic numerical models; and it improves regional understanding of hazard and risk.

Construction of the pumped storage plants (PSP) in Central Russia region is often complicated by landslide processes. The case study of the Zagorsk PSP 120 km north from Moscow describes the geological prerequisites of slope instability, which ignorance at the initial stage of construction work had resulted in massive activation of slope movements. Despite these quite hazardous processes timely arranged protection measures based on complex site investigation, allowed successful stabilization of the landslide-prone slopes and safe operation of this important power facility.

In the assessment of a dam safety with respect to global instability, nominal pore water pressure distributions are often adopted for each stage of the dam life, referring to a hypothetical “expected performance” of the different dam components. The seepage phenomena taking place within the dam may, however, modify substantially the pore water pressure distributions up to make them inconsistent with the nominal ones. With reference to this subject, the present paper represents and interprets the singular pore water pressure distributions measured within an Italian earth dam, pertaining to the typology of zoned earth dam with internal clay core. Pore water pressure interpretation is supported by the representation of the evolution of the measured seepage flows. The work highlights how pore water pressure may differ strongly from the nominal distribution during the first stages of the dam life, when, if nearly undrained conditions take place, pore water pressures are discontinuous as a result of their dependency on total stresses. The work also shows how pore water pressure may assume distributions differing from the expected ones also after some decades of the operational stages, this time as a result of suffusion phenomena induced by the seepage processes within the dam embankment. Measured pore water pressure distribution, suitably interpreted as piezometric heads contours, clearly show how part of the downstream shell contributes to the embankment watertightness.

Nine potentially unstable massifs and rockfall prone sites that could fail partially or completely have been identified downstream from the Chirkey hydropower station in 1980. Four areas in the immediate vicinity from the dam have been anchored, and permanent monitoring of the rest is carried out. An inspection of unstable massif about 400 m thick located 1.1 km downstream from the Chirkey dam on the right bank of the Sulak Canyon has been performed. Shear deformations of some blocks of this massif develop progressively and fresh fissures and slides are observed as several sites. The landslide – rockfall phenomena develop on the steep valley slope composed of fractured rocks (limestone and marl) subjected to unloading and seismic shaking typical of the study area. Slope stability was calculated based on field structural-geological and geophysical investigations and drilling, and the appropriate monitoring system was proposed.

Roads, rails and pipelines often are crossing areas with rock faces and steep slopes in mountainous areas. Rockfalls and debris flows are frequent fast moving landslides, which constitute hazards and can damage infrastructures requiring additional serviceability, crash or bury vehicles and result in death. These type of landslide events are characterised by very fast trigger and evolution and so, even if they are typically preceded by intense rain, they occurs without any clear warning. The first think to do in these cases, is to understand the entity and the distribution of these phenomena along the transportation corridor by means of computational instruments able to compute slope hazard; then consolidation works have to be designed taking the risk distribution along the corridor into consideration; the consolidations or the protection works have to be started where the risk is higher and, therefore, more urgent. In this paper, methods that refer about the geotechnical aspects of fast landslide movements constituting hazard for the transportation network and the consequent mitigation works will be discussed. Some applicative examples are reported too.

Nilgiris district, a renowned hill station in the state of Tamilnadu, India, has a history of damaging landslides. This paper presents field observations and results of preliminary geotechnical investigations on the damages to infrastructure due to rainfall induced landslides during November 2009, which left more than fifty people dead and hundreds homeless. Laboratory tests were conducted on soil samples collected from landslide locations. The soils are of clayey sand and silty sand type with high fine content and low permeability. Case studies of damages caused to roads, railways and buildings are presented. Though the immediate triggering factor for the landslide at many locations was heavy intense rainfall, there were several causal factors like excavation of slope at toe, vertical cutting, loading at crest and defective maintenance of surface drainage systems.

Rockfall hazard comes from two processes: detachment of rock blocks from the upper part of the cliff, and their propagation along the lower part of the slope. Several hazard approaches attempt to assess the probability of propagation, for an assigned rockfall magnitude class, stopping at a specific point from the source area. The probability of reach is evaluated by trajectory simulations, from the distribution of the blocks deposited along the slope, or by empirical approaches such as the reach angle and/or the shadow angle.

The aim of this paper is to compare the results of rockfall travel distances calculated by means of two methods for a cliff impending over a viaduct near the harbour of Salerno. Using the reach angle model, a first scenario was prepared showing three reach probability boundary lines. Using trajectory simulations, another rockfall hazard scenario based on kinetic iso-energy curves was then drawn. Comparison of the two hazard scenarios shows several differences, subsequently analysed in detail.

The D15 cutting is located on the Marrakesh-Agadir motorway, on the stretch between Imintanout and Argana, between kilometres 32 + 460 and 34 + 540 of the project. Measuring approximately 2,080 m long and with a maximum height of almost 125 m, the D15 cutting was designed with 5-m wide berms every 10 m in height and a slope between berms of 1 H:2 V. The excavation of this cutting required moving more than 1.3 M m3 of earth, making it one of the biggest in the world. In late 2009, during the excavation of cutting D15, superficial landslides were detected in the berms built so far. These phenomena of surface instability alerted the owners, represented by Autoroutes du Maroc (ADM), who hired the services of Eurogeotecnica-Euroconsult to study the problem. The preliminary study concludes that there was pathology in the cutting of greater significance than that referring to the surface landslide observed. The report highlighted the fact that it would not be possible to correct the latent effects simply with the surface treatments scheduled at that point by the contractor. These treatments consisted of a containment system based on anchoring systems measuring less than 10 m in length, consolidated by means of a mesh of steel cables. In mid-march 2010 Eurogeotecnica-Euroconsult was contracted by ADM to begin exploration, monitoring and evaluating of the movements than had started, and to supervise the works carried out by the contractor. Following heavy rains, large fissures began to appear in the cutting in the excavation phase, in the berms themserves (following the stratification surfaces) ans behind the crown of the cutting. Subsequently, on 21 and 22 March 2010, a break of some depth ocurred in the southern end of the cutting in the excavation phase when two of the upper berms gave way and the colluvium that covered that part of the slope shifted, with an approximate volume of 50,000 m3. With regard to the notrhern part of the cutting, following the previous break, on the insistence of Eurogeotecnica-Euroconsult, elements were immediately installed that made it possible to monitor the landslide movements in the part of the rock mass, which were shown by the large fissures that appeared and that meant a more global movement than that initially supposed, thereby involving a volume of more than a million cubic metres. This landslide, while showing no evidence signs of acceleration, required immediate decisions to be taken in order to stabilize it. In light of the preliminary reports deriving from the supervision of the works in the cutting and the monitoring and evolution of the movements of the cutting in the northern part, ADM asked Eurogeotecnica-Euroconsult to study the problem, draw un the project and carry out general supervision of the cutting. This intervention was also carried out with technical advice on treating and managing the risks generated by landslides on the slope.

The overall road network in the Principality of Andorra is affected by continuous rockfall hazards from adjacent slopes. To determine the risk of each section of road and establish a priority for actions to be undertaken, a methodology has been developed based on two variables: the rockfall hazardness and the likelihood of impact in road sections based on the average daily traffic (ADT). The aim of the methodology is to define an objective criterion with a parameterization of variables by assigning numerical values to reflect the estimated risk for each road section. The results obtained allow to establish the order of priority for countermeasures and risk management. In those cases where identical results are obtained for various sections, we have used an expert criterion to prioritize a section over another.

The Scascoli Gorge (Bologna – Italy) is bounded by very steep slopes. The right side of the valley is dominated by the Large Scascoli Landslide (20,000,000 m

3

). The left valley floor of the Savena stream is flanked by vertical sandstone walls 40–80 m high, and steep slopes of heavily fractured marl-sandstone multilayers. The most important rockfall known occurred in 1992, 2002 and 2005 when a rock wedge called “Mammellone 1”, collapsed with an estimated volume of 27,000 m

3

destroying a long segment of road and dammed the Savena riverbed. The geological – geotechnical surveys and the installed monitoring systems till 2002, allowed to plan the following interventions: (a) reshaping the residual unstable rock mass in the left valley side (b) removing a shallow earth slide from the right valley side, and consolidating its detachment zone with nails and mesh; (c) reconstructing the road embankment with reinforced soils and gabions; (d) delocalizing a segment of the road from its original path at the foot of a high and wide unstable cliff.

The present paper reports a multi-disciplinary team work, involving professionals, research institutes and public administration, for defining and applying low-impact techniques for risk assessment and mitigation of landslide areas. A study area located at Lugnano in Teverina (Umbria Region, Italy) and interested by landslides triggered by heavy rainfall and affecting important railway and road networks, was considered. A geological field survey has been carried out (including in situ and laboratory tests) in order to define strength parameters to be used in the stability analysis, for the detection of the most active area (residual risk) and implementation of preliminary design. In order to identify landslide surface and estimate the involved volumes, 3D laser scanner acquisition has been performed at different times. The obtained results stress the importance of performing different analysis in the light of reducing the impact of landslides on critical infrastructures by promoting low-environmental and sustainable solutions.

In Canada’s north, slope stability is a critical issue affecting infrastructure. There are several types of landslides and ground hazard features that are directly related to the presence of permafrost: active layer detachment slides, retrogressive thaw flows, solifluction, thermo-karstic depressions, and rock glaciers.

A landslide inventory and preliminary susceptibility assessment of debris flows and rockfalls/rock slides were carried out for a proposed pipeline route along the Yukon Alaska Highway Corridor (YAHC). The YAHC covers a linear distance of 950 km with a 40 km width. A total of 2,018 geohazard features including 1743 landslides were identified, which represents about 1 landslide per 17 km

2

. Prominent landslide types included debris slides (31 %), debris flows and fans (28 %), rock slides (11 %), solifluction (8 %), earth slides/flows (5 %), thermo-karstic depressions (5 %), rockfalls (4 %), and combined retrogressive thaw flows and active layer detachments (1 %). Rock glaciers were also identified (6 %).

The qualitative heuristic debris flow susceptibility map indicates that 73 % of the debris flow deposits occur downstream from a high susceptibility zone and 23 % downstream from the moderate susceptibility zone. For the qualitative heuristic rockfall/rock slide susceptibility map, 76 % of the known failures occur in the high susceptibility zone and 17 % in the moderate susceptibility zone. Thus, as preliminary qualitative landslide susceptibility mapping, this is considered a good correlation between the maps and landslide inventory.

The coastal roads of the Gipuzkoa province, Basque Country, Northern Spain, suffer frequent damage and blockage as a consequence of the instability of slopes. In 2006 the Gipuzkoa Road Conservation Service promoted a study aiming at identifying the locations showing the highest risk and prioritizing actions for road stabilization and protection. In this communication the results obtained with the Rockfall Hazard Rating System (RHRS) modified by Budetta (Nat Hazards Earth Syst Sci. Euro Geosci Union, 4:71–81, 2004), which has been adapted to the specificities of the study road, are presented. First, the index has been normalized by the length of the sections analyzed to allow their comparison. Second, rockfall volume and frequency have been modified to accommodate local conditions of the cut-slopes and their hazard level. Finally, the RHRS has been adapted to account for the occurrence of small-size debris flow events

National Road SS63 is endangered by large scale slope instability phenomena few km north of the Cerreto Pass (northern Apennines, Italy). At the Col Piagneto slope, SS63 was closed two times in the past 50 years after landslide events. In 1974, the collapse of portion of a rock slide triggered a debris slide that buried more than 50 m of the road track. In 2008, the reactivation of an earth slide in eastern portion of the slope damaged about 400 m of the “new” track built to by-pass the 1974 risk area. In order to evaluate if it is worthwhile keeping the old track open to traffic, or it is maybe better to repair the new track a comprehensive study was financed by Emilia Romagna Region. Research methods included: high resolution DEM, landslides mapping, continuous displacement and groundwater monitoring. Results allowed to assess different semi-quantitative risk scenario for the road structures or vehicles.

In mountainous urbanized areas, shallow landslides cause significant, often unpredictable, hazard conditions. Landslides may involve and destroy infrastructures, kill people. Source areas are often located along the road network, representing a recurring situation also during not heavy rainstorms in Northern Tuscany. The landslides are generally first time debris slide-flows, occurring in peculiar environments: colluvium/debris slope cover (0.5–2 m thick), semipermeable-impermeable bedrock, hollow shaped slope, high slope gradient. Despite little size, they cause damage and deaths owing to their high velocity and erosion power. The source area along the road network is generally associated to the lack of efficient drainage systems. In fact, the concentration of uncontrolled runoff downslope creates an “unnatural” increase in pore pressure that the only rainfall should not have produced. This generates reaching and exceeding of the local critical rainfall threshold, making landslide hazard assessment more difficult. As example, in October 2010, almost 60 % of the landslides source area in the Massa area was located along the road network.

Few years ago, during the start-up works for the realization of a tunnel entrance, a shallow translational landslide occurred. Following this event detailed engineering-geological surveys of the slope were performed and an integrated monitoring system, including also a Terrestrial SAR Interferometer (TInSAR), was built. Based on the time series of displacement semi-empirical approach was applied to the anchored bulkheads. Simultaneously an engineering-geology model was devised for a stress–strain numerical analysis which was performed by the finite difference code FLAC 6.0.

For the rack railway of Montserrat a hazard assessment has been performed to evaluate rockfall protection degree after the intensive protecting works carried out during the last 10 years. A qualitative analysis has been done to determine the hazard in 39 initiation areas defined by levels and basins, considering the rockfall propagation in the basis of reach angle method to be implemented in GIS. Despite all constraints of such type of approach, an overview on risk along the railway is obtained to assess the protection level obtained thanks to the protective investment done by the railway office, and also to prioritize the remaining hazard focus.

The paper focuses on the description of a landslide event occurred along the Gran Sasso d’Italia Massif (Central Apennines, Italy) and on the interpretation of the possible causes that determined some unusual secondary effects occurred at the base of the slope. The study was carried out by coupling the results of field surveys with the processing of an available seismic record generated by the rockfall. The recorded velocimetric data were processed in order to assess the evolution of the rockfall in terms of number of main impacts and energy dissipation.

The Cassas landslide is located in NW Italian Alps and impinges on a corridor encompassing main transportation lines between Italy and France, hydro facilities and a village. The largest potential reactivation phenomenon is considered to be of approximately 10 Mm

3

, with a maximum depth of the main body of approximately 80 m and an average slope of 20–25°. The slide was the object of monitoring for more than a decade and special attention was devoted to it in view of the 2006 Torino Winter Olympics (the highway at its toe was the main Olympic lifeline). A formal quantitative risk assessment (QRA) and related monitoring program were performed. The integrated approach yielded interesting predictive/observational results, which drove stabilization actions including a drainage tunnel and the compilation of a highly sophisticated alert/crisis plan in case of future accelerations.

During the construction of the south portal of the tunnel Baldaia I along the SS106 motorway in Calabria, unexpectedly large and continuous displacements of the earth retaining structures occurred leading to a precautionary suspension of the excavation works. To study the kinematics of the observed instability phenomenon, inclinometer probes were used together with the topographic monitoring of the portal structures; it was found that the unstable mechanism was deep-seated, block-type and extending over the entire slope. In this paper the site investigation activities carried out to understand the origin of the instability process are presented. The interpretation of the observed behaviour is then given together with the description of the remedial measures suggested to safely complete the construction of the tunnel. The link between the time evolution of the instability and the sequence of the excavation works, which turned out to be an important issue in the process, is also discussed in some detail.

Much knowledge has been accrued over the years regarding landslide triggers, failure mechanisms and debris movement mechanics. In addition, technical frameworks for hazard and risk assessments have been developed for practical use. However, there remain considerable uncertainties in respect of natural terrain landslide assessment and design of risk mitigation measures. The need to consider the impact of climate change further complicates the issue given the fuzziness of the state of the art in this area. The main problems relate to knowledge gaps and potential errors in engineering judgement.

In this paper, the key uncertainties associated with natural terrain landslides and adverse effects of climate change, together with difficulties faced by the geotechnical profession, are highlighted. The strategy and approaches that may be adopted to manage these uncertainties are discussed.

Landslides are one of the most destructive natural disasters in Malaysia besides floods. The socio-economic losses due to landslides are significant and set to continue growing as population growth sees development expanding to encompass further potentially unstable hillside areas. These losses can be reduced by means of effective planning and management which involves legal, policy and institutional framework and guidelines of best practices for every stage of development. In this paper, existing laws, policies and guidelines applied since as early as 1960 to minimise losses due to landslides are discussed along with proposed best practices.

The opportunities of artificial neural networks model application to landslide forecasting are considered, namely prediction of landslide types and parameters of landslide damage area. The data collected by observers with different qualification are used as predictors, in doing so the reliability of prediction increases with higher professional skill of observers and accomplished research work. Real data from number of landslide-prone areas in southern Kyrgyzstan were used.

Features of the contemporary activity in landslide slopes of the north-west coast of the Black Sea within city area of Odessa (Ukraine) are considered. Results of their study utilising the method of gamma-mapping were described. The possibilities of using remote sensing methods were estimated.

El Forn Landslide is one of the largest landslides in the Pyrenean area. To date, it has not been thoroughly studied or characterized by what is known of the existence of movements and their evolution (residual deformation, acceleration, more or less active areas, etc.). This paper presents the device implementation of a large active landslide inhabited from the Middle Ages, situated in the Andorran Pyrenees and its associated risk management. In 2000, the Govern d’Andorra initiated several actions to manage the risk associated with large slides, with an initial zoning of the territory in relation to different natural hazards (large landslides, rockfalls, debris flows and shallow landslides). In 2002 a map of buildability of the landslide was carried out, and in 2005 Andorran Government raised about the possibility of monitoring the most active areas of the slide. In 2007 work began on instrumentation that lasted until early 2009 in order to characterize the terrain (through surveys of 200m deep) and placing measurement devices for monitoring all the slopes of El Forn Landslide. There are ongoing periodic readings of the instruments with the aim of identifying areas of greater movement and activity, but, given its characteristics (speed, size, etc.), it is not expected that one could get reliable results until a few years.

The village of Cancia, close to Cortina d’Ampezzo (Italian Dolomites), has been many times hit by destructive debris flows that caused deaths among dwelling people and severe damage to houses and roads; the most recent of these disastrous events happened in July 2009 and caused the death of two people. This study considers the cases of the most calamitous past debris-flow events: the morphological settings of the initiation area are illustrated, along with an analysis of the processes that led to the formation of this dangerous phenomenon. In particular the critical interaction between geological and anthropic systems are examined showing the hazardous effects of the realization of a tourist development in the area. A critical review of the countermeasures so far proposed concludes the study.

The Kastamonu Castle is one of the magnificent monuments of the Kastamonu province (Turkey) located on a steep sandstone hill with Eocene age. The surrounding settlement around the castle suffered from numerous rockfall events in the past. Rockfalls after an initial block toppling are controlled by a bedding plane and two joint sets existing in the sandstone. The rockfall potential along the entire castle perimeter was evaluated by means of three-dimensional (3-D) rockfall analyses using the ROTOMAP software. Rockfall initiation was modelled along a detachment line situated just below the castle walls. The results indicate that the maximum run-out distances around the castle exceed the settlement boundary on the western, southern, and eastern sides. The northern part of the castle is less critical due to lower slope gradient. In order to protect the settlement from falling blocks, vital remedial measures are suggested.

The Tartagal River basin is placed in the Sub-Andean Hills in northwestern Argentina. In this area the town of Tartagal, in Salta Province, with 55,000 habitants, is located. At this site the contribution river basin is approximately 100km

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. Between 2006 and 2009 the region was affected by extreme events of different characteristics, which created a risk to human lives, productive infrastructures and communications. In 2006, large rainfalls above average values generated landslides, with the appearance of large-scale gullies. In 2007, remedial works were carried out. In 2009, an avalanche of water and sediment with logs came down the Tartagal River reaching the city’s main avenue bridge. After the 2009 event, structural and non-structural measures of short, medium and long term were implemented.

Since the 1980s the risk studies have definitely been unable to follow the growth and the density of favelas, and some communities have started to trigger the first records of accidents in areas hitherto stable. The mapping made in 2010 is today the largest geological-risk database in the country. Besides technical information, the survey has also shown the types of intervention to be implemented according to the degree of risk and the type of verified occupation, – vital data to prioritizing the public-authority actions. Out of 1,602 favelas and informal settlements in the city, 25% have currently occupied areas with some occurrence probability of mass-movement processes. Together, the assessed areas cover about 13.5km

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, located in the outskirt regions. Nowadays, about 115,000 people are living in landslide-prone areas in the capital. As a result, the low-income intervention projects by the government have been reassessed and adjusted, prioritizing housing, social-educational infrastructure, and basic-sanitation actions in areas of greatest susceptibility.

This paper presents the results of a geo-environmental study carried out in the urban area of Dessie town, one of main urban centres of Ethiopia with 200,000 inhabitants. In this area, landslides heavily interact with a disorderly expanding human settlement, inducing high risk conditions for human lives, buildings, infrastructures and economic activities. Based on a detailed geological and geomorphological field survey and mapping, a GIS-based analysis of landslide susceptibility has been applied to the Dessie basin, one of the “hanging” tectonic depressions located along the western Afar margin. Landslide hazard and risk maps were successively produced for the central sector of Dessie town. The landslide risk map and the related report will constitute the starting point for a possible plan of risk mitigation in the urban area of Dessie.

In the last 4 years Messina Municipality has been hit by rainfall events that triggered a great number of debris flows. Due to 2009 event ENEA started landslide hazard researches in the south of the Municipality. Messina territory (210km

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) is located at the NE culmination of Peloritani Range, formed by seven metamorphic Units covered by late orogenic terrigenous formations and by Plio-Pleistocene deposits. Steep slopes lead to high erosion rates, that increased in last years because of intense rainfall. The first step of the hazard assessment method is an inventory of landslides, followed by the detection of landslide parameters. Through GIS analysis of this parameters landslide susceptibility is assessed. Geomorphological analysis allows evaluating the runout and energy of the future events. Rainfalls data analysis allows definition of triggering threshold for the area. These parameters will be tested in a test site field for the measurement of soil saturation.

After very intense rainfalls and pre-failure little ground movements, a large landslide occurred in San Fratello on 14th February 2010. San Fratello is a little town on the Nebrodi Mts., a chain in north-east of Sicily, Italy. The landslide is one of the most devastating phenomena occurred in Sicily. In fact it extends over an area of about 100 hectares and has caused enormous damage in the little town: about 300 buildings have been damaged, tens of which completely destroyed, about 2,000 inhabitants have been evacuated. This landslide is very complex for several reasons: it includes different but complementary ground movements; it develops in structurally complex formations; the water table is close to ground level. Based on the results of experimental investigations and back-analyses, geological and geotechnical landslide models have been implemented. Designed stabilization works also include new technologies, such us trench drains realized by means of permeable concrete secant piles having a length of 12.00m.

This work describes the extreme event of landslides occurred in January 2011 in the Rio de Janeiro mountainous region and discusses its relationship to the spatial and temporal variation of critical and prior rainfall. Interviews in the field let us establish the landslide initiation timing around the automatic pluviometer stations which supply detailed data on the rainfall intensity. The study concludes that the accumulated rainfall during the last months associated with high rainfall levels over 24h, along with local conditions like the direct impact of lightning and tremors resulting from landslides, formed the relevant conditions for thousands of landslides.

In this paper preliminary results of scientific research of the Kostanjek Landslide (the City of Zagreb, Croatia) are presented, which are achieved in the frame of a scientific Japanese-Croatian project. The aim of this research is to develop a base for planning of integrated real-time geodetic and geotechnical monitoring of the landslide. Despite long history of landslide movements (approximately 50 years) and geotechnical investigations conducted in 1998 and 2008, present landslide model does not ensure information about landslide activity state, activity style, activity distribution and velocity of movement. On the basis of preliminary investigations it is concluded that determination of landslide geometry, soil properties and hydrogeological conditions require additional research (geomorphological, geomechanical and hydrological) which need to be conducted before design of monitoring system.

Natural-risk levels assessment related to debris-flow and flood occurrence is a crucial process for the development of proper land management policies in densely urbanized alluvial-fans of the Alpine region. Mitigation measures are built to protect edified areas lowering natural-risk level below defined thresholds and to allow socio-economic development at local scale, especially in mountainous areas, where urban expansion is strongly conditioned by local morphology and natural processes dynamics. In 2009, SEA Consulting was instructed by Bruzolo Municipality (Susa Valley, Piedmont Region, NW Italy) to assess the efficacy of a levee along the Pissaglio riverbanks designed to protect a densely populated area. The study was conducted considering debris-flow hazard by following two different approaches: monodimensional (“Colate detritiche”, that implements Voellmy and Takahashi equations) and bidimensional (RASH3D code, assuming a Voellmy rheology) models. Flood hazard was assessed by means of the program HEC-RAS. The results of the study are presented in this paper.

This essay presents the methodological procedures and criteria to landslide risk mapping on urban settlement unstable areas (slums) in Sao Paulo (Brazil). The methodology was developed by researchers of the Instituto de Pesquisas Tecnológicas (Institute for Technological Research – IPT), with the collaboration of other professionals, based on their own experience. The procedures are determined based on geological and geotechnical investigations, probability analysis of the occurrence of processes related to external dynamics, identification of risk areas, analysis of possible consequences of the processes and information of appropriate intervention measures for the different cases.

The geotechnical properties and the stability of a landslide site in south eastern Nigeria were assessed. The soils associated with the landslides have low bulk density, high porosity and permeability. The slip surface was impermeable black shale. The landslide site is under intense hydrostatic pressure manifested in numerous springs and oil (gasoline) seepage. Shearing tests show the shear strength parameters are very low, and that the dominant process controlling the deformation of the soils was liquefaction. Normally and over-consolidated samples all liquefied, with over-consolidated samples having higher brittleness index than the normally consolidated ones. Scanning electron microscope analyses show that there are micro planes of weakness in the undisturbed soil samples meaning that the soils are inherently unstable and needs only a minor increase in shear stress on the slope to fail. Significant excess pore pressure generation began only after the soils had been displaced considerably. Stability analysis obtained a factor of safety of 0.78. The concern is that about 95% of the slopes in south eastern Nigeria are founded on soils with similar properties investigated. Urgent action is needed, therefore, to prevent further loss of lives and property.

Protection of cultural heritage from landslide is a science at the border between Engineering Geology and Conservation of Cultural Heritage. It needs both a highly qualified know-how and funds, due to the importance of the site to protect and the possibly additional difficulties during the works execution. Cultural Heritage protection requires also an integrated approach among different disciplines, including restoration, and very deep investigation in each different sector of knowledge. Since a limited knowledge in a single step of the process may affect the entire process. In detail, when dealing with Cultural Heritage, there is the need of a correct geological and geotechnical model and relationship with slope stability. Data collecting do have to emphasize the requested need. Simplified approach can lead to a misunderstanding of processes and then to a wrong mitigation measurement.

The present paper reports general concepts about the approaches and methodologies as well as the importance of proper data collection and elaboration, low environmental impact monitoring and new technologies concerning Conservation strategies and Cultural heritage protection. Some case studies emphasize the above concepts.

In a progressively developing scope of tourism the interconnection of relief, as the basis of landscape, and recreation has become a topical question. The study of these connections opens new perspectives for scientific activities, since it allow more efficient use of natural resources, as well as ensure the safety of recreation. Approach to identify and evaluate recreation and geomorphologic potential is based on the notion of “fields of attractiveness and risk”. Comprehensive study of these “fields” gives a quantity, which indicates a complex functional suitability of territory for recreational purposes.

The component-wise assessment of geomorphic risk and attractiveness was made for three sample areas with high contemporary geodynamics (South Iceland, Sicily, Kamchatka peninsula). These territories along with high recreational attractiveness represent enormous risks induced by active relief dynamics.

The presented research deals with the stability of the rock slopes in the foundation of selected medieval castles in Slovakia.

In the first part a static analysis of the 45 selected medieval castle rock slopes was carried out, where more than 12,000 potentially unstable blocks were analyzed and factor of safety in static condition was calculated using key block theory implemented in the Kbslope module of PTworkshop software.

Based on the results of the static stability analysis a pseudo-static analysis was performed adopting the seismic acceleration in accordance to the Slovak technical norm -Seismic actions on structures. This was implemented by calculating vectors of horizontal force acting upon the shear failure in the direction of slope face with the zero vertical component. The obtained results showed, that if we do not take into account the tapered blocks which represented 81% from the 12,217 investigated blocks in the static conditions, 14% of blocks were unstable. This figure further increased to 23% in the pseudo-static condition, when the seismic acceleration was taken into account.

Rapid onset natural phenomena, such as earthquakes, floods and landslides, pose a major threat to cultural heritage and visitors in Petra The paper reports first results of a feasibility project, in cooperation with UNESCO and PNT, aimed at envisaging the stability conditions of the slope-forming rocks of the Siq that is the spectacular entrance for tourists to the monumental area of Petra. A field analysis was conducted to reconstruct, although preliminarily, the characteristics and orientation of discontinuities, main failure modes of potential unstable blocks, magnitude of phenomena, geomechanical parameters of materials. A first rock-fall hazard assessment has been defined and some potential monitoring techniques have been analyzed. Results will be used for the implementation of a forthcoming project addressed to landslide risk analysis of the Siq, as fundamental management tool of a master plan for sustainable tourist exploitation of the site.

Through the centuries coastal erosion and landslides have modified the landscape of the coastline in SE Britain, also affecting the monuments and archaeological heritage of the Roman Shore Forts and modern military installations. The back analysis of the past/recent modifications can reveal the type of impacts produced and how the perception of the built environment has been altered from the former configuration. The precious availability of historical mapping and documentation (e.g., photographs, etchings, prints, old video tapes) can provide pictorial records of architectural portions/artefacts now missed or damages occurred due to past natural hazard events. Combining historical information with updated field observations, geoarchaeological analysis was performed to estimate the impacts of coastal erosion and landsliding on the conservation of both coastal sites and isolated monuments, which testify the long history of defence and seapower of Great Britain.

Famous because of its deepness and beauty of the landscape, Colca Valley is one of the main places of tourist attraction in Peru. Maca and Lari are two of the valley villages, facing each other on opposite banks of the Colca River. High slope energy is only one of the factors causing a widespread landslide activity, triggered primarily by seismic activity.

A study carried out into a capacity building project (FORGEO) was focused on mapping landslide source areas in the territory of both the villages. Starting from an inventory of several previous phenomena occurred in the area, an evaluation of the local predisposing parameters to these events was used as input for susceptibility and hazard GIS based analysis. An assessment of exposure of structures and infrastructures was also performed, detecting residual risk condition in the territories of both villages. The role of rainfall and groundwater in local landslide processes is stressed in this paper as well as the effectiveness of an adequate water management in landslide risk reduction and sustainable land use planning.

The recent development of new remote sensing instrumentations, such as ground-based radar and terrestrial laser scanner, has encouraged the implementation of these non-invasive devices during diagnostic campaigns for the monitoring and geotechnical characterization of the instability processes in historic sites. This work presents the results of the research activities performed on the archaeological area of Roman Forum, Rome (Italy) and on the Citadel fortifications of Gozo (Malta). Ground-based radar demonstrated potentials for monitoring and surveillance at ‘single monument scale’, allowing real time warning in case of anomalies and deviations from the expected structural behaviour of the ancient masonry, thanks to the integration with the 3D model obtained from terrestrial laser scanning. On the other side, laser scanning provided fundamental base to calculate the probability of occurrence of instability mechanisms interesting, in the case study of Gozo, the Citadel rock mass, also providing a useful indication for the installation of on site monitoring network.

ERS1/2 (1992–2000), ENVISAT (2002–2008) and RADARSAT1 (2003–2007) satellite data, processed with Persistent Scatterer Interferometry, are exploited to study the historic urban area of Agrigento, Italy, whose structural stability is threatened by retrogressive landslide processes. Up to 2–5mm/year of line-of-sight displacement are observed in 1992–2008 on the staircase and the left aisle of the Cathedral. Displacement acceleration to 13–15mm/year is measured in July 2006–May 2007, in the northern portion of the churchyard, in front of the left aisle. The areas moving at higher rates, located at the edge of the NW slope of Girgenti hill, correspond to those showing major structural damages. Aggravation of structural instability of the Cathedral and increased risk of collapses is observed in 2011.

The present work aims at reconstructing the stratigraphy at the ancient citadel of Machu Picchu by using a passive seismic technique to implement a landslide stability model and a risk mitigation plan. After the warning launched in March 2001 by the scientific community about the potential collapse of the citadel as a consequence of potential landslide event, different studies have been promoted to reconstruct the landslide activity and to suggest mitigation measures for the protection and conservation of Machu Picchu cultural heritage.

Italy is the country that owns most of the world cultural heritage and is affected by a very large number of landslides widespread throughout its territory. Aim of the work is to define a methodology, developed on GIS platform, in order to assess cultural heritage exposed to very slow and extremely slow mass movements using: SAR data, the Italian Cultural Heritage database and the Italian Landslide Inventory. The methodology has been developed at provincial level and tested on Macerata province. A single building approach has been also performed on six cultural heritage. The proposed methodology could be applied to all cultural heritage sites in Italy to identify priorities and plan field surveys, detailed studies and monitoring systems.

The Maaloula village is situated in the Palmyrides Mountains (Syria), close to the anti Lebanon orogenic zone. The morphology of the village is the result of important tectonic activity, which resulted in an impressive narrow valley intersecting an anticline. Maaloula is well known as the place of the first example of Christianity sepulture, such as the Santa Tekla tomb (IV c. A.D.). Local population are still speaking traditional Aramaic language.

Purpose of the work is to evaluate ongoing consolidation activities and to propose further development and implementation.

The paper is describing the main rock engineering features of the Maaloula site and some recommendations for a proper implementation of a consolidation strategy for the conservation of Santa Tekla monastery. The latter is located below a small and isolated hanging blocks as well as adjacent to an important rock slide.

The main features of the site have been synthesized from the all available documents and from some direct field survey and laboratory tests. All data have been utilized to establish a model for slope evolution. Some remarks and comment on ongoing consolidation works and other proposed projects are also reported.

The Sacred Grove of Bomarzo (Central Italy), usually known as Monsters Grove, is a unique historic garden and comprising allegoric sculpture on huge rock block. These are the result of a quaternary geological and geomorphological activity, developing from the deposition of volcanic ignimbrite from Cimino apparatus topping plio-pleistocene marine clay, and the subsequent erosion from the Tiber river evolution. This last one was very important during the last glacial age. The final result is a continuous and rapid evolution of the flank of the valley, producing a retrogressive phenomena affecting the whole volcanic plateau, presently hanging over the valley. Due to the presence of rigid materials covering plastic formations, the area is mainly characterized by the presence of typical landslides phenomena such as rock falls isolating huge block falling down from the upper part of the valley, forming debris accumulation. The park of Monsters of Bomarzo was realised in 1552 as “Villa of Wonders” to be the only one of it’s kind in the world. It was devised by the architect Pirro Ligorio (he completed the Cathedral of Saint Peter in Rome after the death of Michelangelo and built Villa d’Este in Tivoli) on commission of Prince Pier Francesco Orsini, called Vicino, only to vent the heart broken at the death of is wife Giulia Farnese. Vicino Orsini created a labyrinth of symbols, where “Ladies and Knights” might look for what they most wanted and wonder till they got lost. He populated the “sacred wood” with monsters and tortoises, obelisks, nymphaums and giant statues. After Vicino Orsini’s death nobody cared any longer for this jewel of mannerist art, that only after centuries of oblivion has been recently saved and restored.

Tiwanaku is an Archaeological World Heritage Site, located at an elevation of 3,885m.a.s.l., south of Lake Titicaca, in the altiplano or high plateau region of the Republic of Bolivia. It is in the province of Ingavi, department of La Paz, 60km from the city of La Paz. Major highlight of the site is the Akapana pyramid, an extensive earth mound hill, with only few remaining of the original coverage of stone and coloumns.

The pyramid is suffering for extensive erosional phenomena such as: rill erosion, mass movement and creeping;

The majority of the phenomena mentioned above are caused by the uncontrolled flow of the rainwater, which flows freely through the depressions (natural or cultural) but which, also, infiltrates and deforms the materials of the deposits and appears to be affecting the stability of the internal structures. From site inspeciton it is possible to note the large toe deposit originated by the erosion/dismantling of the earth mound, some potential surficial mass movement and creeping and the evidence of deformed walls, suggesting internal deformation to the mound. Also, in grey is the large rubble left from the excavation of the Colonia Period.

With reference to the erosion of the mound, there is a clear evidence (rill erosion and small valleys on the mound) that a large part of the original structure has been affected by erosion and deposited at the base or foot of the pyramid; moreover, it is not possible to exclude that the stepped design in the shape of the “chacana” or Andean cross could have played some roles in such erosion.

The present paper is showing major erosional problems and suggesting mitigation measurements, possibly based on local traditional techniques.

The ancient fortified city of San Leo is built on a limestone plateau. The rock slab is tectonized and crossed by several families of joints and faults, while the underlying foundation of the rocky cliff is composed of gentle clay slopes, modelled in the so-called “Argille Scagliose” geological units. The differential weathering of the upper rock formation with respect to the ductile clays has produced ledges and overhangs on the cliff face. Furthermore, weathering and/or movement of the underlying clays has caused the opening and widening of vertical fractures in the brittle limestone rock masses, diffused over the entire rock mass. The evolution of plastic movements (slides and flows) in the underlying clay units might undermine the limestone slab and endanger the stability of the rocky cliff, thus posing risk to the fortified city of San Leo and its notable cultural heritage. In this paper, historical and recent slope instability events are described, on the basis of historical documents and modern investigations.

The paper reports the preliminary stage of a study on the evolution of the Velaber Minus valley and of its interaction with the slope instabilities on the Palatine western slope. The Palatine hill is among the historical hills of the Ancient Rome, as it hosts remnants of Republican temples, Imperial palaces and Archaic ruins. First the geological evolution of the valley was reconstructed on the basis of stratigraphical data. Then a stress–strain numerical modelling reproducing such evolution has been performed. Finally, it is here reported the intervention for the mitigation of local slope instabilities.

The article synthetically describes more than 30 years of intense activities (studies, plans and interventions) aimed at consolidating the Orvieto Hill, and highlights the peculiarity of a multidisciplinary approach to the study of the instability phenomena and to the definition of the design solutions. The studies required continuous research activities and the use of innovative solutions and technologies addressed to the consolidation and to the monitoring of the Orvieto Hill.

In this context, the Observatory for the Permanent Monitoring and Maintenance of the Orvieto Hill was set up by the Regional Government of Umbria. The Observatory is the Regional instrument for the control and management of the territory and of the remediation works.

The complex of the Roman villas of the ancient Stabiae is located over a morphological terrace near the edge of a steep slope that separates the archaeological site from the urban area of Castellammare di Stabia (Gulf of Naples). The hill is being affected by debris and earth flows that have endangered some ancient structures of the complex. The present work has reconstructed the slope dynamics and causes by means of a geomorphological and geotechnical approach coupled with geophysical investigation. A slope stability modelling, calibrated with landslide historical information and direct survey, has provided main failure mode and magnitude of recent events. Geophysical investigation has permitted to analyse the state of superficial terrains under prominent archaeological structures, providing important information on potential failure surfaces that can be mobilised in the near future in the lack of urgent mitigation measures in the most hazardous sectors of the slope.

A part of earthen embankment along the outermost gallery at the west moat in Angkor Wat, Cambodia, failed due to heavy rainfall in October, 1997. The moat was excavated along the squired area dedicated for the temple. The embankment was manmade compacted sandy soil, laterite block, and sandstone on the surface. Soil mounds were found in the moat at several points in front of the embankment. These mounds had been found as accumulation of eroded soil from embankment.

Geotechnical cause of losing stability of the embankment was discussed and identified as piping failure.

The failed site was reconstructed using by modern technique of geotextile to give enough strength against stability.

In saturated soils, drainage systems are one of the most effective remedial measures against slope instability due to their capacity to reduce pore-water pressure in the subsoil, increasing the shear strength of the soil. Due to their relative cheapness, subsurface drainage systems are widely used, also in combination with other stabilization works. Moreover, they provide a suitable solution to stabilization in a large number of cases, even when the landslide is very deep and structural measures are not effective (Popescu (2002) Landslide causal factors and landslide remedial options. Keynote lecture. In: Proceedings of the third international conference on landslides, slope stability and safety of infra-structures, Singapore, pp 61–81). In this paper the main subsurface drainage systems are described in terms of their conventional and innovative technologies, their limits and advantages. The design approaches in the relevant literature are also reviewed.

In this paper, a landslide in a large coal mine site in Shanxi province, China is taken as a case to study. The effect of underground mining on the stability of the old landslide and the reactivation mechanism were analyzed. The mining displacement greatly reduced the strength of the soil. The tensile cracks provided infiltration path for surface water which reduced the physical and mechanical properties of the soil of sliding zone. The gob movement and deformation in the front of landslide played a dragging role in the damage of the landslide. The boundaries and the sliding surface of the landslide have been determined by the ways of engineering geological mapping, drilling, geophysical investigation and deformation monitoring. The landslide is zoned based on the topography, material composition and deformation characters. The mitigation measures of ordered retaining structures in the landslide and anti-sliding pillar in the mine have been carried out according to the deformation characteristics, geological and environmental conditions and mining demand. Monitoring data show that the landslide keeps stable as the mitigation measure putting into effect.

The paper presents finite element (FE) modelling and simulation of a newly developed rockfall protective cable-net structure in Japan, named the Long-span Pocket-type Rock-net (LPR). A reference case LPR was taken and its element-level laboratory tests and structure-level full-scale field tests conducted in the past were utilized for the calibration and verification of the numerical model exercised on the platform of the code LS-DYNA. The ultimate goal of this research is to shade lights to the targeted design guideline of LPRs. Therefore, deliberately, a simplified (equivalent) but yet rigorous approach has been adopted without going into interface-level detailing. Moreover, a number of confusions unaddressed by the state-of-the-art literatures regarding the effects of the changes in various impact load characteristic-parameters resulting into the same specified kinetic energy have been investigated using the FE model. Furthermore, an investigation on the performance of the existing energy dissipator installed in LPR and the scope of its future modification is discussed.

Rainfall is one of the important factors which make slope unstable. After the piles are used to strengthen the landslide, the landslide seepage field will be influenced especially under rainfall condition.

The landslide stress field will change with the seepage field, which will affect the landslide stability. In order to design anti-sliding piles reasonably, the effectiveness of anti-sliding piles under rainfall condition should be studied.

Wulidui landslide in Three Gorges reservoir area was taken as an example and its engineering geology was introduced. By choosing reasonable and practical soil-water characteristic curve and permeability function, the mechanic model was obtained under two typical conditions: (a) 175 m water level; (b) 3-day rainfall with intensity of 150 mm/day. With GEOSTUDIO software package, the stress field and strain field at different time without and with anti-sliding piles were simulated in SIGMA code by incorporating the seepage field obtained in SEEP code. Based on all these analyses, the landslide stability with and without anti-sliding piles before and after rainfall was evaluated.

The Volga River slope in the Ulianovsk City engineering protection systems and their elements are described and discussed, along with the results of its present state inspection. Three methods of the landslide-prone area stabilization have been proposed: method of underground water catchment by use of pipes installed by the directional drilling; the “Geocomposit” method of the sliding zone compaction and armoring; method of additional loading of the landslide toe by coarse material and by the weight of heavy structures placed here. To develop these techniques it was proposed to arrange a special test site with a real-scale drainage system to divert water from the water-bearing horizons and to develop technology of soil massifs stabilization by the internal dowelling of the sliding surface. The latter should increase a stability of a landslide-prone slope. To increase material strength at the sliding zone the “Geocomposit” method will be used, i.e. the injection of the hardening compound to form dowels at the boundary between the stable and moving soil masses.

The effectiveness of the stabilization measures, particularly deep drainage wells, have been analysed in a complex landslide affecting a major motorway in Southern Spain. A complete failure analysis of this instability, named as the Diezma landslide, has been performed considering different steps: (1) The slope before and after the A-92 motorway construction; (2) The slope during the 2001 Diezma landslide; (3) The slope after the stabilisation measures; (4) The slope at the 2010 reactivation; (5) Possible future reactivation. The good performance of the drainage wells was verified successfully by means of electrical resistivity tomography cross-sections. The future stability of the Diezma landslide depends on the correct performance of the drainage systems after periods of heavy rain. In addition, the reactivation of the Diezma landslide is expected in the case that a low magnitude earthquake (M

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4.0–5.0), relatively common in the study area, occurs close to the landslide location.

Erosive phenomena are very diffused all over the world. Over the years different techniques of ground protection and renaturation have been developed. Among them, an outstanding and innovative natural technology uses only natural perennial grass plants with deep roots and allows to operate in areas where pedoclimatic conditions were until a few years ago considered prohibitive for the development of vegetation. Such technology also appears promising with respect to phenomena of surface instability of fronts: the deep root grasses may induce mechanical and hydraulic effects on slope equilibrium that typically increase the shear strength of soil. The mechanical effects of plant roots result from the root/soil interaction processes; the hydraulic effects derive from the significant reduction of water content and degree of saturation of soil caused by the presence of grass. Final goal of the research is the quantitative evaluation of such effects through modeling and implementation of a computing algorithm.

The information contained in this document refers to the use of high capacity flexible systems for slope stabilizations in volcanic terrains in La Gomera (Canary Islands – Spain). On the TF-711 road, civil jobs for platform improvement began in July 2007. In two different winter seasons, ending 2009 and 2010, heavy rainstorms hit the area, provoking large amounts of rock falls and landslides from slopes which had been protected with traditional technologies used in the area. A proven, but not widely extended technology was proposed to solve the problem. It is based on a mesh made of high tensile steel wire with yield strength of 1,770 N/mm

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, combined with steel rope reinforcement, and bar anchorages. Such solutions provide very versatile systems with a high retention capacity. It is being proved as definitive and the most efficient solution for the frequent instabilities affecting the road, also minimizing the environmental impact on a highly ecologically protected area. The problem and the solution are discussed here, focussing on the description of the systems.

The work illustrates the design solutions prepared and implemented to mitigate dangers and geomorphological risks in the cliff of Civita di Bagnoregio (Central Italy). Civita is located on a tuff cliff for centuries subject to landslide phenomena that have resulted in the progressive retreat of the slopes and today jeopardize the very existence of the town, so much so that Civita is widely known as the “dying town”. In recent decades, Civita has been affected by new and serious occurrences of landslides, focusing the attention of the town’s administrators and the wider scientific community on the problem of safeguarding the town’s existence, both with respect to civil defense and the conservation of its environmental and architectural heritage. The proposed solutions are the result of more than 20 years of analyses, elaborations and theoretical modeling, and represent one of the most innovative models toward the consolidation and securing of historical towns at risk of landslides. The work proposes to take advantage of the lessons learned in the past toward securing Civita di Bagnoregio, and highlights the need to mitigate such effects on the cultural heritage through interventions that are capable of effectively containing the movement of the cliff, while being at the same time sustainable and of low impact. The paper illustrates the fundamental tenets behind the methodologies and procedures for sustainable intervention and for the identification, on the basis of a careful and rigorous understanding of the ongoing natural phenomena, of appropriate techniques and technical choices for the implementation of works that have a minimal impact on the existing cultural landscape. This paper analyses thoroughly the approach and investigations that have led to the structural reinforcemets of the north side of the tuff cliff of Civita from reinforced concrete shaft excavated in the tuff. These works have had no visual or material impact on the valley or the slopes of Civita, and have made it possible for the first time to carry out an innovative consolidation program, a welcome departure from more traditional and less effective methodologies.

Officine Maccaferri has developed BIOS, a simplified as well as realistic design approach for the calculation of the flexible structural facing of soil nailing. The approach shows that the most important property of this kind of application is membrane stiffness of the mesh. With the procedure of BIOS is possible to reduce the timing of design and get a cost effective intervention. Anyway the designer judgment is required for a better evaluation of the critical factors like the slope morphology, the admissible displacement and settlement, the presence of water and erosion processes.

The purpose of this paper is to describe the case history of an enhanced and integrated monitoring system in an open pit marble quarry in Carrara (Italy). The current marble production comes from the more and more improved cutting technologies that have been applied since the 1970s, leading to large excavations, both open pit and underground, than can quickly reach impressive and unusual shapes. This is the context where in the last few years some specific studies have been developed and implemented, most of them taking into account the rock mass static conditions or a single sliding block identified by a specific stability evaluation code (e.g. Key block theory by Goodman and Shi (Goodman RE, Shi GH (1985) Block theory and its application to rock engineering. Prentice Hall Inc., London, pp 338pp)). The paper shows a traditional monitoring system made up of several vibrating wire transducers implemented by an innovative georadar survey system. A preliminary comparison between the experimental results coming from the two methods has been described.

The village of Acqualoreto is included in a high risk landslide area. The area coincides with part of a large paleo-landslide. The paleo-landslide does not show any evidence of possible re-activation, however, but many active or dormant landslides, classified as slips or flows, have been identified along parts of the accumulation body.

In order to resist the gravitational movement, a series of measures aimed primarily at protecting the city have been constructed. In the preliminary phase the design was to build up a flexible retaining wall together with a system of draining wells aimed to intercept groundwater.

In the execution phase, after numerous technical problems, it was necessary to modify the solution proposed, and to intervene proceeding from the top to the foot of the landslide.

Danylan landfill operated from 1955 until its closure in 1971 just prior to introduction of legislation with an emphasis on environmental protection that would have required the landfill to have a license. In early 2004, and following a prolonged period of rain, an approximately 18 m high landslip occurred at the north-western end of the former landfill. The landfill involved approximately 4,000 m

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of uncontrolled refuse tip material in a matrix of made ground. Testing of the landslide debris indicated that, if left unattended, its chemical composition could pose a significant chronic risk to human health, flora, fauna and controlled waters. Restoration of the landslide to its original profile included the engineered placement of the failed waste debris back into the slip scar with the aid of Tensar polymer geogrid reinforcement providing a robust, cost effective, sustainable, environmental friendly and maintenance free engineering solution.

A compendium of structural and non-structural mitigation measures for different landslide types has been developed as part of the EC sponsored SafeLand project, to be used both as a basis for a web-based “toolbox” also developed as part of the project and more generally as a resource for a wide variety of users. Emphasis has been placed on providing a rational framework applicable to all the measures listed in the compendium, classifying them in relation to the terms of the “risk equation” (hazard, vulnerability, elements at risk) addressed by the specific mitigation measure. Hazard mitigation measures are subdivided in relation to the physical processes involved. The compendium is supplemented by fact sheets that provide specific guidance on hazard mitigation measures, including a brief description, guidance on design, schematic details, practical examples and references, as well as subjective (provisional) ratings of their applicability in relation to the descriptors used for classifying landslides. More details of the various mitigation measures considered may be found in Deliverable 5.1 of the SafeLand project.

Like many other countries in Asian region, Thailand has been affected by various natural disasters including flash floods and landslides. The 2006 flash floods and landslide in the northern part of the country have affected 4 provinces leaving 87 people dead, 29 missing with more than 4,000 houses left totally and partially damaged. Exclusive of cost of damaged houses and individual property, the estimated total cost of damage is THB 308,615,331.

The paper investigates the vulnerability and risk of the communities living in the hilly parts of Uttaradit and Sukhothai Provinces in the Northern Thailand that are frequently hit by flash floods and landslides. The root causes of the impacts of the disasters are further discussed based on findings from fieldwork conducted a month after occurrence of the disaster event.

Learning from the flash floods and landslide disasters in the Northern Thailand, the paper recommends effective flashfloods and landslide management strategy that can empower local governments in Thailand to manage flashfloods and landslide risk thus reducing future impacts on vulnerable communities.

Risk induced by rockfall on a road is a relevant topic for designer. In this paper, we discuss a risk analysis management procedure for roads subject to rockfall phenomena using a new method specifically developed, named RO.MA. In this method rockfall risk is calculated using an event tree approach. Two different examples of application are proposed and discussed.

The examples of the engineering investigation errors, which have resulted in an appearance of the unfavourable situations in the process of construction, have been considered. The recommendations concerning a set of the engineering investigations in the landslide area of highways have been worked out for various stages of designing taking into consideration a highway category. A basic diagram of installation landslide protection design, which is based on a risk assessment taking into account an investigation volume, is suggested.

The paper deals with evaluation and mapping of landslide hazard of an area located in the Archaeological Historic and Natural Park of the Rupestrian Churches in Matera. This park and old urban area of Matera town (“Sassi di Matera”) were recognized by the UNESCO World Heritage list since 1993.

The studied site, named “Balvedere Chiese Rupestri” is to be found along the top of a deep canyon (“Gravina di Matera”) and contains many, valuable full hand-hewn, rupestrian churches.

For its lithological, structural and geomorphological features, this area is affected by a widespread and by an intense slope instability, this phenomenas lead large and rapid falls, toppling and sliding of rock blocks. This geomorphological structure causes diffuse and significant structural-failures processes that involve most of the precious rock heritages.

The evaluation and mapping of landslide susceptibility have been assessed using an artificial neural network (ANN), this system employing a back propagation-learning algorithm.

This method requires the definition of appropriate thematic layers, that allow to parameterize the area under study. The parameters adopted in this study are: lithology, elevation, angle and aspect of the slope, hillshade, fracture density, kinematic hazard index of planar and wedge sliding and toppling. The results show that most of investigated area is characterized by a high landslide hazard.

This paper aims to create a model for analyzing the systemic vulnerability of a complex urban area at landslide risk. The proposed approach of vulnerability evaluation differs from traditional methods as it provides an analysis of “Systemic Vulnerability” measuring the direct and indirect consequences of a simulated event on the territorial system. For example, the collapsing of a bridge, apart from the intrinsic loss, could bring about the interruption of an entire traffic zone, or interrupt the functions of a hospital with consequences on the health system in general as well as on mobility, communication, efficiency of civil protection forces, etc.

GIS technology allows the automated application of the method by creating a model that processes, analyzes and displays data in the form of maps. The model proposed was shown to be able to support the territorial planning and the appropriate management of an emergency in case of landslide event.

The paper shows a methodology for defining flexible high-detailed debris flow invasion hazard maps. The methodology relies on both an adequate knowledge of the study area, assessed by an accurate analysis of its past behavior, together with a reliable numerical model for simulating debris flows on present topography. The approach is based on the application in parallel computing environment, of an advanced Cellular Automata model, SCIDDICA, for simulating debris flows coupled with an innovative analysis technique in the context of hydro-geological risk assessment. The model has been applied to the northern sector of Monte Pendolo (Sorrento Peninsula), affected by several landslides in historical time. On the basis of geological survey and statistic of past events, several possible source areas have been hypothesized and potential future landslide scenarios simulated by using the SCIDDICA model, previously calibrated on past events of similar scale and type.

The Trafoi rockslide is very similar to the Val Pola landslide before it evolved in a catastrophic rock avalanche in 1987. The Trafoi rockslide was recognized and mapped on the basis of geomorphic evidences such as double crests and detachment niches/scarps as well as geologic proxies such as gravitational offset of distinctive bedrock levels and trenching and fracturing of rock masses. In order to assess the activity status of the landslide, not discernible from field evidences only, periodic GPS monitoring on 11 benchmarks was started in 2007 and continued until 2010 with static-rapid measurements repeated three to four times per year. Results have shown that portions of the rockslide move at some cm/year rate. This highlights the potential for a possible evolution of the mass movement and the necessity of hazard scenarios mapping and run-out modelling. In order to define volume of possible detachments scenarios, digital aerial photo-interpretation were used together with High Resolution DEM and information collected from geomechanical field survey. The Trafoi rockslide is among the test sites of the ongoing European project “Monitor II”, that is proposing the usage of hot spots in the process domain as a practical mean to describe hazard scenarios. Following such approach, simplified hazard and risk scenarios were schematized on the basis of the data collected with monitoring and analysis of ongoing and potential slope instability processes.

The availability of geological and geomorphological data represents an important element to support local authorities in land management policies and the design of mitigation measures to reduce natural risk levels. These data allow to improve decision makers awareness during the process of design and construction of civil works both public and private. SEA Consulting srl, was appointed by the Verduno municipality (Cuneo Province, Italy), in order to provide the inventory and the classification of the geological and geomorphological elements of the Tanaro Valley sector falling within the municipal territory. In this area the geological setting is characterized by shallow and deep landslides connected to a karst system developed in the Vena del Gesso Formation (Upper Messinian), represented by gypsum, which exerts a relevant influence on groundwater and runoff behaviour. This study was accomplished in different and consequential steps which allowed (1) to relate the field survey with the previous works and geological studies, (2) to realise the inventory with an appropriate and effective standard process for data field acquisition and (3) to develop and to implement a database to store field information. Information is organized in way to be read both on computer and on paper support. Thematic forms provides data related to specific aspects of the karsts shape such as the geographic location, morphology, evolution state, relationship to the anthropic activities, geologic and geomorphologic setting. The geographic features and the associated information are also available on a GIS. Specific command tools on database forms allow to easily read information and to perform specific queries. Finally, the study allowed (1) to improve awareness on land processes, (2) the monitoring of the evolution of the karst phenomena and their relationship with runoff dynamics and (3) to develop an operative tool for checking and managing municipal territory data by local public managers.

Deep seated landslides have historically caused extensive damage to land and structures. These large failures are usually controlled by several triggering factors, and one of the most important is deemed to be the change in pore-water pressure inside the slope.

To define the 3D geological model of complex landslides an integrated approach which combines the results of surface and subsurface surveys is often mandatory.

This paper aims to present the integrated approach adopted to study the Premana landslide, a deep seated landslide in the North of Italy. The outputs of the geophysical surveys have been combined with geological observations and have been used to model slope stability related to different water table levels in order to define the critical thresholds of pore-water pressure. Considering the complexity of the landslide, the heterogeneity of the geological features and the limitations inherent to each methodology, different approaches were used to study the Premana landslide.

Vegetation significantly influences the hydrological and mechanical properties which are relevant for the stability of shallow soils along sloping surfaces. In view of the complexity of soil plant hydrological interactions, the quantification of root mechanical reinforcement remains a challenge. In this paper we couple root reinforcement models with a quasi-dynamic wetness index (QDI), which is specifically designed for estimating the local wetness conditions by accounting for the character of the upslope topography and the time of the lateral soil moisture distribution. The overall modelling strategy can be effectively employed for assessing the relative hazard of shallow landslides accounting for vegetation patterns and dominant forest management practices. The methodology is applied to an area located in Northern Tuscany, recently interested by several shallow landslides.

Landslide risk mitigation is a societal pressing need in many countries; early warning system supported by monitoring and predictions represent effective risk reduction measures, provided that warning thresholds are properly set. Mapping of landslide risk is extremely complex: slope movements have a wide range of velocity, size and run-out, thus their magnitude and impact on exposed goods can be either very low or very high, depending on site conditions, materials involved and triggering factors. Rainfall is accepted as a major triggering factor in many types of slope movement, including rapid, shallow soil slips and, episodically, deeper landslides. Early warning can be defined as the entirety of actions to take during the lead-time, namely the time interval between the moment of the event prediction and the moment of the landslide impact. In this context, the improvement of analysis methods able to increase this time is essential.

The paper presents a joint application of the FLaIR Hydrological Model of rainfall-induced landslide triggering (Sirangelo and Versace Proceedings of XXIII Convegno Nazionale di Idraulica e Costruzioni Idrauliche, Firenze, III, pp D361–D373, (1992)) and an event-based point rainfall stochastic model (Capparelli et al. XXXIII IAHR Congress, Vancouver, Aug 2009, ISBN 978-94-90365-01-1, pp 6812–6819, (2009); Greco et al. Early warning of rainfall-induced landslides based on empirical mobility function predictor. Submitted for publication in Natural Hazards, (2011)). The first one identifies the landslide triggering conditions by defining a mobility function Y(t), obtained through the convolution of infiltrated rainfalls and a transfer function ψ(t), the second one is a stochastic model of the external structure of point rainfall height series, allowing to predict in real time the residual duration and rainfall height of a partially observed rain storm. The combination of the two models improves the effectiveness of an early warning system, since it allows to gain larger lead times. The potentiality of this approach is shown with regards to the slope of Pizzo d’Alvano (Campania region- South Italy), where mudslides occurred on May 5th 1998, severely hitting the town of Sarno.

Over recent years, the link which exists between meteoric precipitation and terrain mobility has been the focus of many studies, even in the hydrologic and hydraulic sectors. These studies are the logical consequence of the close connection between the occurrence of each type of terrain instability and rains which, directly or indirectly, influence a slope. The analytical approaches which can be found in the specific technical literature differ greatly in terms of methodology and formulation.

The paper describes analytical work on the hydrogeological events which have occurred in the Region of Calabria over the winters from 2008 to 2010. Empirical-hydrologic models were adopted to analyse the landslides. In fact, use was made of the FLaIR model which, starting from rainfall analysis, allows the critical triggering threshold to be identified. Comparison was made of the events foreseen by the model and those which actually occurred, estimating the number of Correct Alarms (CA), Missed Alarms (MA) and False Alarms (FA), which are the principal indicators for evaluating how efficacious and efficient the various models are.

The results presented in this work show that the model is highly capable of predicting the different events, with a limited number of MA.

Penang is one of the areas in Malaysia that have corrugated and hilly topography. Construction activities in these areas are increasing day by day, primarily for residential and commercial purpose. Such rapid development put the environment in risk by causing flood, changes of climate, landslides etc., and becomes a threat to the life and property of local inhabitants. This paper describes the risk assessment for Paya Terubung in Penang that are exposed to such risk. Assessments are made by using rating systems and are developed after modification from other existing guidelines and requirements. Results from the evaluation are also shown in environmental risk map with the application of Geographical Information System (GIS) to identify high, moderate or low risk areas. The results show that 12 % of project sites are at high environmental risk in Paya Terubung, 44 % at medium environmental risk and others at low environmental risk.

“Disaster!!! Mother Nature has devoured their loved ones and belongings leaving only a symbol of what was there. Thousands came, some out of curiosity, some to offer assistance and others to provide solutions. But would any of these assure their right to live in this world where they belong in the future, without coming in to conflict with the Mother Nature? Could anyone provide the lasting solution? Who can wipe their tears off?”