Physical Modeling of Landslide Generated Tsunamis and the 50th Anniversary of the Vajont Dam Disaster

NASA Astrophysics Data System (ADS)

McFall, Brian C.; Mohammed, Fahad; Fritz, Hermann M.

2013-04-01

The Vajont river is an affluent of the Piave River located in the Dolomite Alps of the Veneto Region, about 100km north of Venice. A 265.5 m high double curved arch dam was built across a V-shaped gorge creating a reservoir with a maximum storage capacity of 0.169 km3. A maximum water depth of 250 m was reached by early September 1963 during the third filling attempt of the reservoir, but as creeping on the southern flank increased the third reservoir draw down was initiated. By October 9, 1963 the water depth was lowered to 240m as the southern flank of Vajont reservoir catastrophically collapsed on a length of more than 2km. Collapse occurred during reservoir drawdown in a final attempt to reduce flank creeping and the reservoir was only about two-thirds full. The partially submerged rockslide with a volume of 0.24 km3 penetrated into the reservoir at velocities up to 30 m/s. The wave runup in direct prolongation of slide axis reached the lowest houses of Casso 270m above reservoir level before impact corresponding to 245m above dam crest (Müller, 1964). The rockslide deposit came within 50m of the left abutment and towers up to 140m above the dam crest. The lateral spreading of the surge overtopped the dam crest by more than 100m. The thin arch dam withstood the overtopping and sustained no damage to the structural shell and the abutments. The flood wave dropped more than 500m down the Vajont gorge and into the Piave Valley causing utter destruction to the villages of Longarone, Pirago, Villanova, Rivalta and Fae. More than 2000 persons perished. The Vajont disaster highlights an extreme landslide tsunami event in the narrowly confined water body of a reservoir. Landslide tsunami hazards exist even in areas not exposed to tectonic tsunamis. Source and runup scenarios based on real world events are physically modeled in the three dimensional NEES tsunami wave basin (TWB) at Oregon State University (OSU). A novel pneumatic landslide tsunami generator (LTG) was

Reinvestigation and analysis a landslide dam event in 2012 using UAV

NASA Astrophysics Data System (ADS)

Wang, Kuo-Lung; Huang, Zji-Jie; Lin, Jun-Tin

2015-04-01

Geological condition of Taiwan is fracture with locating on Pacific Rim seismic area. Typhoons usually attack during summer and steep mountains are highly weathered, which induces landslide in mountain area. The situation happens more frequently recent years due to weather change effect. Most landslides are very far away from residence area. Field investigation is time consuming, high budget, limited data collected and dangerous. Investigation with satellite images has disadvantages such as less of the actual situation and poor resolution. Thus the possibility for slope investigation with UAV will be proposed and discussed in this research. Hazard investigation and monitoring is adopted UAV in recent years. UAV has advantages such as light weight, small volume, high mobility, safe, easy maintenance and low cost. Investigation can be executed in high risk area. Use the mature aero photogrammetry , combines aero photos with control point. Digital surface model (DSM) and Ortho photos can be produced with control points aligned. The resolution can be less than 5cm thus can be used as temporal creeping monitoring before landslide happens. A large landslide site at 75k of road No. 14 was investigated in this research. Landslide happened in June, 2012 with heavy rainfall and landslide dam was formed quickly after that. Analysis of this landslide failure and mechanism were discussed in this research using DEMs produced prior this event with aero photos and after this event with UAV. Residual slope stability analysis is thus carried out after strength parameters obtain from analysis described above. Thus advice for following potential landslide conditions can be provided.

The formation and failure of natural dams

USGS Publications Warehouse

Costa, J.E.; Schuster, R.L.

1987-01-01

Of the numerous kinds of dams that form by natural processes, dams formed from landslides, glacial ice, and neoglacial moraines present the greatest threat to people and property. The most common types of mass movements that form landslide dams are rock and debris avalanches, rock and soil slumps and slides, and mud, debris, and earth flows. The most common initiation mechanisms for dam-forming landslides are excessive rainfall and snowmelt and earthquakes. Landslide dams can be classified into six categories based on their relation with the valley floor. Type I dams (11%) of the 81 landslide dams around the world that were classifed do not reach from one valley side to the other. Type II dams (44%) span the entire valley flood, occasionally depositing material high up on opposite valley sides. Type III dams (41%) move considerable distances both upstream and downstream from the landslide failure. Type IV dams (1%) are rare and involve the contemporaneous failure of material from both sides of a valley. Type V dams (1%) are also rare, and are created when a single landslide sends multiple tongues of debris into a valley forming two or more landslide dams in the same surfaces, that extend under the stream or valley and emerge on the opposite valley side. Many landslide dams fail shortly after formation. Overtopping is by far the most common cause of failure. Glacial ice dams can produce at least nine kinds of ice-dammed lakes. The most dangerous are lakes formed in main valleys dammed by tributary glaciers. Failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam. Cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel. Warmer temperate-ice dams tend to fail by sudden englacial or subglacial breaching and drainage. Late neoglacial moraine-dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several

Large landslides induced by the 2008 Wenchuan earthquake and their precursory gravitational slope deformation

NASA Astrophysics Data System (ADS)

Chigira, Masahiro; Wu, Xiyong; Wang, Gonghui; Uchida, Osamu

2010-05-01

2008 Wenchuan earthquake induced numerous large landslides, of which many large landslides had been preceded by gravitational deformation. The deformation could be detected by linear depressions and convex slopes observed on satellite images taken before the earthquake. Ground truth survey after the earthquake also found the gravitational deformation of rocks, which could be predated before the earthquake. The Daguanbao landslide, the largest landslide induced by this earthquake, occurred on a slope of bedded carbonate rocks. The area of the landslide, based on measurements made from the ALOS/PRISM images is 7.353 km2. Its volume is estimated to be 0.837 km3 based on the comparison of the PRISM data and the SRTM DEM. It had an open V-shaped main scarp, of which one linear part was along a high angle fault and the other was approximately parallel to the bedding strike. The upslope edge of the V-shaped main scarp was observed as 2- km long linear depressions along the ridge-top on satellite image before the landslide. This indicates that this slope had been already destabilized and small movement occurred along the bedding planes and along the fault before the event. The Wenchuan earthquake pulled the final trigger of this landslide. The major sliding surface was along the bedding plane, which was observed to dip 35° or slightly gentler. It was warped convex upward and the beds were fractured, which suggests that the beds were slightly buckled before the landslide. This deformation may correspond to the formation of the linear depression. The Tangjiashan landslide in Beichuan, which produced the largest landslide dam during the earthquake, occurred on a dip slope of shale and slate. The geologic structures of the landslide was observed on the side flanks of the landslide, which indicated that the beds had been buckled gravitationally beforehand and the sliding surface was made along the bedding plane and a joint parallel to the slope surface. The buckling

Computational hydraulics of a cascade of experimental-scale landside dam failures

NASA Astrophysics Data System (ADS)

Wright, N.; Guan, M.

2015-12-01

Abstract: Landslide dams typically comprise unconsolidated and poorly sorted material, and are vulnerable to rapid failure and breaching, particularly in mountainous areas during high intense rainfalls. A large flash flood with high-concentrated sediment can be formed in a short period, and the magnitude is likely to be amplified along the flow direction due to the inclusion of a large amount of sediment. This can result in significant and sudden flood risk downstream for human life and property. Numerous field evidence has indicated the various risks of landslide dam failures. In general, cascading landslide dams can be formed along the sloping channel due to the randomness and unpredictability of landslides, which complexes the hydraulics of landslide dam failures. The failure process of a single dam and subsequent floods has attracted attention in multidisciplinary studies. However, the dynamic failure process of cascading landslide dams has been poorly understood. From a viewpoint of simulation, this study evaluates the formation and development of rapid sediment-charged floods due to cascading failure of landslide dams through detailed hydro-morphodynamic modelling. The model used is based on shallow water theory and it has been successful in predicting the flow and morphological process during sudden dam-break, as well as full and partial dyke-breach. Various experimental-scale scenarios are modelled, including: (1) failure of a single full dam in a sloping channel, (2) failure of two dams in a sloping channel, (3) failure of multiple landslide dams (four) in a sloping channel. For each scenario, different failure modes (sudden/gradual) and bed boundary (fixed /mobile) are assumed and simulated. The study systematically explores the tempo-spatial evolution of landslide-induced floods (discharge, flow velocity, and flow concentration) and geomorphic properties along the sloping channel. The effects of in-channel erosion and flow-driven sediment from dams on

Late Pleistocene landslide-dammed lakes along the Rio Grande, White Rock Canyon, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reneau, S.L.; Dethier, D.P.

1996-11-01

Massive slump complexes composed of Pliocene basaltic rocks and underlying Miocene and Pliocene sediments flank the Rio Grande along 16 km of northern White Rock Canyon, New Mexico. The toe area of at least one slump complex was active in the late Pleistocene, damming the Rio Grande at least four times during the period from 18 to 12 {sup 14}C ka and impounding lakes that extended 10-20 km upriver. Stratigraphic relationships and radiocarbon age constraints indicate that three separate lakes formed between 13.7 and 12.4 {sup 14}C ka. The age and dimensions of the ca. 12.4 ka lake are bestmore » constrained; it had an estimated maximum depth of {approx}30 m, a length of {approx}13 km, a surface area of {approx}2.7 km{sup 2}, and an initial volume of {approx}2.5 x 10{sup 7} m{sup 3}. The youngest landslide-dammed lakes formed during a period of significantly wetter regional climate, strongly suggesting that climate changes were responsible for reactivation of the slump complexes. We are not certain about the exact triggering mechanisms for these landslides, but they probably involved removal of lateral support due to erosion of the slope base by the Rio Grande during periods of exceptionally high flood discharge or rapid incision; increased pore pressures associated with higher water tables; higher seepage forces at sites of ground-water discharge; or some combination of these processes. Seismic shaking could also have contributed to triggering of some of the landslides, particularly if aided by wet antecedent conditions. 54 refs., 19 figs., 3 tabs.« less

Himalayan Lake- and River-Impacting Landslides and Ice Avalanches: Some So Deadly, Some No Problem

NASA Astrophysics Data System (ADS)

Kargel, J. S.; Karki, A.; Haritashya, U. K.; Shugar, D. H.; Harrison, S.

2017-12-01

Scientific attention to landslides and ice avalanches in Nepal was heightened by the 2015 Gorkha earthquake. However, landslides and ice avalanches— some deadly— are frequent in this mountainous, glacierized country and across High Mountain Asia. River blocking landslides (RBLs) often create dangerous situations due to upstream impoundments and downstream landslide dammed outburst floods (LDOFs). Factors affecting RBL hazards include: Volumes and masses of ice, rock, and water; shape factors of the valley and landslide; grain size-frequency distribution; river hydrograph; and seasonal and weather factors. These factors affect processes such as slumping and erosion of the RBL by overflow or piping, buoyant lifting of dam material, melting of a landslide ice core, liquefaction, overfill overtopping or tsunami overtopping by subsequent landslides into the impoundment, and the volume and peak discharge of an LDOF. Not all processes aggravate hazards; a high ice:rock ratio, for example, can result in immediate tunneling by the river with no subsequent impoundment. A dam composed of mainly boulders with few fines likewise can prevent effective damming; however, a wide spectrum of the particle-size-distribution can make a long-lasting, benign dam. The most hazardous RBLs include those creating large dams and rapidly-filled impoundments, but which can rapidly and catastrophically break up, especially at sites of repeated terrain collapses. The particle size-frequency of a landslide dam depends substantially on bedrock lithology and structure. Vulnerabilities and warning times also affect whether an upstream impoundment flood or LDOF will exert a large toll. For landslide susceptibility assessments, usual treatments involving mountain slopes, valley shape, and seismic activity should be complemented by quantitative measures of bedrock lithology and weathering state, the potential energy and distribution of unstable masses, and recorded historic or prehistoric RBLs in

Glacier and landslide feedbacks to topographic relief in the Himalayan syntaxes

PubMed Central

Korup, Oliver; Montgomery, David R.; Hewitt, Kenneth

2010-01-01

Despite longstanding research on the age and formation of the Tibetan Plateau, the controls on the erosional decay of its margins remain controversial. Pronounced aridity and highly localized rock uplift have traditionally been viewed as limits to the dissection of the plateau by bedrock rivers. Recently, however, glacier dynamics and landsliding have been argued to retard headward fluvial erosion into the plateau interior by forming dams and protective alluvial fill. Here, we report a conspicuous clustering of hundreds of natural dams along the Indus and the Tsangpo Rivers where these cross the Himalayan syntaxes. The Indus is riddled by hundreds of dams composed of debris from catastrophic rock avalanches, forming the largest concentration of giant landslide dams known worldwide, whereas the Tsangpo seems devoid of comparable landslide dams. In contrast, glacial dams such as river-blocking moraines in the headwaters of both rivers are limited to where isolated mountain ranges intersect the regional snowline. We find that to first-order, high local topographic relief along both rivers corresponds to conspicuously different knickzones and differences in the type and potential longevity of these dams. In both syntaxes, glacier and landslide dams act as a negative feedback in response to fluvial dissection of the plateau margins. Natural damming protects bedrock from river incision and delays headward knickpoint migration, thereby helping stabilize the southwestern and southeastern margins of the Tibetan Plateau in concert with the effects of upstream aridity and localized rock uplift. PMID:20212156

Great landslide events in Italian artificial reservoirs

NASA Astrophysics Data System (ADS)

Panizzo, A.; de Girolamo, P.; di Risio, M.; Maistri, A.; Petaccia, A.

2005-09-01

The empirical formulations to forecast landslide generated water waves, recently defined in the framework of a research program funded by the Italian National Dam Office RID (Registro Italiano Dighe), are here used to study three real cases of subaerial landslides which fell down italian artificial reservoirs. It is well known that impulse water waves generated by landslides constitute a very dangerous menace for human communities living in the shoreline of the artificial basin or downstream the dam. In 1963, the menace became tragedy, when a 270 millions m3 landslide fell down the Vajont reservoir (Italy), generated an impulse wave which destroyed the city of Longarone, and killed 2000 people. The paper is aimed at presenting the very satisfactorily reproduction of the events at hand by using forecasting formulations.

The Sasso Pizzuto landslide dam and seismically induced rockfalls along the Nera River gorge (Central Italy).

NASA Astrophysics Data System (ADS)

Romeo, Saverio; Di Matteo, Lucio; Melelli, Laura; Cencetti, Corrado; Dragoni, Walter; Fredduzzi, Andrea; De Rosa, Pierluigi

2017-04-01

The seismically induced landslides are among the most destructive and dangerous effects of an earthquake. In the Italian contest, this is also documented by a national catalogue that collects data related to earthquake-induced ground failures in the last millennium (CEDIT database). In particular, Central Italy has been affected by several historical landslides triggered by significant earthquakes, the last of which occurred in August-October 2016, representing the Italian strongest event after the 1980 Irpinia earthquake (Mw 6.9). The study presents the effects of recent seismically induced rockfalls occurred within the Central Italy seismic sequence (October 30, 2016) along the Nera River gorge between Umbria and Marche. The study area is completely included in the Monti Sibillini National Park, where the highest mountain chain in the Umbrian-Marchean Apennine is located. Most of rockfalls have affected the "Maiolica" formation, a stratified and fractured pelagic limestone dating to the Early Cretaceous. The seismic sequence produced diffuse instabilities along the SP 209 road within the Nera River gorge: boulders, debris accumulations and diffuse rockfalls have been mapped. Most of boulders have size ranging from 0.3 to 2.0 m in diameter. Although several strong quakes (Mw > 5) occurred during the August-October sequence, only the main quake triggered the Sasso Pizzuto rockfall producing a landslide dam along the Nera River. The landslide appears to have originated as a wedge failure, which evolved to free fall when the rock block lost the contact with the stable rock mass. In other words, the quake produced the "explosion" of the rock wall allowing the rockfall process. Once the rock mass reached the toe of the slope, it was broken triggering a rock avalanche that obstructed both the Nera River and SP 209 road. With the aim to estimate the total volume of involved rock, a field survey was carried out by using a laser rangefinder. Remote measures were acquired

Hazard assessment of landslide and debris flow in the Rjeina river valley, Croatia

NASA Astrophysics Data System (ADS)

Wang, Chunxiang; Watanabe, Naoki; Marui, Hideaki

2013-04-01

The Rječina River extends approximately 18.7km long and flows into the Adriatic Sea at the center of Rijeka City, Croatia. Landslide, debris flow and rockfall are main geohazards in the middle part of the Rječina river basin. The zone between the Valići reservoir dam and the Pasac Bridge is particularly the most unstable and hazardous area in the river basin. The Grohovo landslide in the middle part of the river basin is located on the valley's slope facing southwest and situated at just downstream of the Valići dam. This landslide is the largest active landslide along the Adriatic Sea coast in Croatia. Assuming that serious heavy rainfall or earthquake occurs, it is most likely to occur two types of geohazard event. One scenario is that the debris deposited on the Grohovo landslide will move down to the channel of the Rječina River and dam up the river course. Another scenario is that the slope deposits on the landslide will be mixed with water and subsequently turn into a debris flow reaching to Rijeka City. We simulate both two cases of the formation of landslide-dam and the occurrence of debris-flow by two integrated models using GIS to represent the dynamic process across 3D terrains. In the case of the formation of landslide-dam, it is assumed that slope deposits will move downhill after failing along a shear zone. GIS-based revised Hovland's 3D limit equilibrium model is used to simulate the movement and stoppage of the slope deposits to form landslide-dam. The 3D factor of safety will be calculated step by step during the sliding process simulation. Stoppage is defined by the factor of safety much greater than one and the velocity equal to zero. The simulation result shows that the height of the landslide-dam will be nine meters. In case of debris flow, the mixture of slope deposits and water will be differentiated from landslide by fluid-like deformation of the mobilized material. GIS-based depth-averaged 2D numerical model is used to predict the

Landslides Triggered by the 12 May 2008, M 7.9 Wenchuan, China Earthquake

NASA Astrophysics Data System (ADS)

Harp, E.; Jibson, R.; Godt, J.

2009-04-01

The 12 May 2008, M 7.9 Wenchuan earthquake in eastern Sichuan Province of China triggered tens of thousands of rock falls, rock slides, rock avalanches, and deep, complex, landslides. Of the approximately 87,000 deaths caused by the earthquake, more than 20,000 have been attributed to landsides. Numerous villages were buried by large landslides. Air-blasts resulting from the rapid failure and movement of landslides were observed and documented from numerous eye-witness accounts. More than 100 landslide-dammed lakes were created by the earthquake, 33 of which were evaluated to determine if spillway construction was necessary to minimize flooding by future breaching of the landslide dams. Spillways were ultimately constructed on at least 16 landslide dams. Preliminary observations in the field and from satellite imagery indicate that the most common types of landslides were rock falls and rock slides that ranged in size from several hundred cubic meters to several hundred thousand cubic meters in volume. There were hundreds to perhaps as many as one thousand landslides exceeding 1 million cubic meters in volume. The largest landslide identified using Jaxa's Alos/Prism satellite imagery (2.5 m resolution) is nearly 1 billion cubic meters in volume and is located approximately 12 km north-northeast of the city of Hanwang. This landslide appears to have resulted from the failure of a 1.5-km section of ridge crest that now occupies most of the adjacent valley to the northeast; its toe spills over the next ridge crest to the northeast. The satellite imagery of 4 June 2008 shows two small lakes dammed by the slide debris. Within the mountainous areas in the near-field zone of shaking, rock slides dammed chains of lakes in many drainages. Sections of streams 2-3 km long have been completely covered by rock debris as of the 4 June imagery The debris from the triggered landslides is being redistributed rapidly by post-earthquake rainfall. A 100-year rainstorm in September

Landslides in the western Columbia Gorge, Skamania County, Washington

USGS Publications Warehouse

Pierson, Thomas C.; Evarts, Russell C.; Bard, Joseph A.

2016-11-04

volcaniclastic sedimentary units. Approximately two-thirds of the mapped landslide area comprises landslides that have remobilized parts of older slides, and 37 percent of these reactivated slides have involved reactivation of material from two or more older slides. The largest two recent landslides have volumes ≈1 km3 and runouts ≈6 km. One of these, the Bonneville landslide, temporarily dammed the Columbia River almost 600 years ago, and subsequent dam-break flooding inundated downstream areas. The other, the Red Bluffs landslide, slid into the river adjacent to the Bonneville landslide but apparently did not form a landslide dam. Another such landslide rapidly sliding into the Columbia River today could have a catastrophic impact on downstream communities and on the transportation and energy-distribution infrastructure of the Pacific Northwest.

Supporting response with science: the Oso, Washington, landslide

NASA Astrophysics Data System (ADS)

Godt, J.

2014-12-01

On 22 March 2014 a large, rapidly moving landslide impacted the community of Steelhead Haven, near Oso, Washington, killing 43 people. The slide displaced about 8 million m3 of sand and silt from a 200-m high glacial terrace destroying 40 homes and burying more than 1.0 km of State Route 530. The landslide temporarily dammed the North Fork of the Stillaguamish River flooding an area of about 1.4 km2. The unusually long travel distance, in excess of 700 m from the base of the slope, and apparent speed of the slide led to the great loss of life and destruction. Landslide science was critical in supporting the response to the disaster. Landslide monitoring, process understanding, pre- and post-event high-resolution digital topography, and numerical simulations were used to advise search operations. Recognizing that buildings and their contents were swept tens to hundreds of meters from their original locations, maps of deposit thickness, and estimates of landslide trajectories were used to develop safer and more efficient search strategies. Teams of county, state, and federal scientists, engineers, and specialists were formed to assess the stability of the landslide dam and to monitor stream flow and the level of the lake impounded by the slide, and to assess the geomorphic response of the river to the landslide for gauging future effects on flood hazards and aquatic ecosystems. Another scientific team assessed the threat of additional landslide activity to search operations. This team's activities included establishing a communications protocol among landslide watch officers and search operations, deploying instrument platforms developed for use on volcanoes (Spiders) to remotely detect ground movement by means of GPS technology and to detect vibrations indicative of landslide movement using seismometers. The team was responsible for monitoring and integrating data from the Spiders and other instruments and making determinations with regards to the potential for

Geomorphic impacts, age and significance of two giant landslide dams in the Nepal Himalayas: Ringmo-Phoksundo (Dolpo District) and Dhampu-Chhoya (Mustang District).

NASA Astrophysics Data System (ADS)

Fort, Monique; Braucher, Regis; Bourlès, Didier; Guillou, Valery; Nath Rimal, Lila; Gribenski, Natacha; Cossart, Etienne

2014-05-01

Large catastrophic slope failures have recently retained much attention in the northern dry Himalayas (1). They play a prominent role in the denudation history of active orogens at a wide range of spatial and time scales (2), and they impact durably landforms and process evolution in upstream catchments. Their occurrence mostly results from three different potential triggers: earthquakes, post-glacial debuttressing, and permafrost melting. We focus on two examples of giant rock slope failures that occurred across and north of the Higher Himalaya of Nepal and assess their respective influence on the regional, geomorphic evolution. The Ringmo rockslide (4.5 km3) results from the collapse of a mountain wall (5148 m) cut into palaeozoic dolomites of the Tethysian Himalayas. It caused the damming of the Suli Gad River at the origin of the Phoksumdo Lake (3600 m asl). The presence of glacial till at the very base of the sequence suggests the rockslide event is post-glacial, a field assumption confirmed by cosmogenic dating. Two consistent 36Cl ages of 20,885 ±1675 argue for a single, massive event of paraglacial origin that fits well with the last chronologies available on the Last Glacial Maximum in the Nepal Himalaya. The persistence of the Phoksumdo Lake is due to its dam stability (i.e. high lime content of landslide components) and to low sediment flux from the arid, upper Suli Gad catchment. The Dhampu-Chhoya rock avalanche (about 1 km3, area extent 10 km2) was derived from the northward failure of the Kaiku ridge, uphold by north-dipping, upper crystallines of the Higher Himalaya. It dammed the Kali Gandaki River, with complex interactions with the Late Pleistocene ice tongues derived from the Dhaulagiri (8167 m) and Nilgiris (7061 m) peaks. Both the rock avalanche and glaciers controlled the existence and level of the "Marpha Lake" (lacustrine deposits up to Kagbeni). Again, consistent 10Be ages of 29,680 ± 1015 ka obtained from two large blocks (>1000 m3

Depth of Small Scale Landslide in Slate Area : Case of 2009 Typhoon Morakot in Ai-Liao River, South Taiwan

NASA Astrophysics Data System (ADS)

Chen, T. C.; Yen, H. Y.; Zhou, F. L.

2015-12-01

This study focuses on the depth and magnitude of the small scale landslide in slate area in Ai-Liao-Shi catchment, South Taiwan. Landslide inventory of 2009 Typhoon Morakot, 5×5 m DEM, and aero photo have been interpreted by GIS software to assess the slope type and the scale of landslide events. The research database includes 276 landslides which orthographic projection areas are smaller than 1 ha. The slopes were also classified into dip, orthoclinical-dip, escarpment, and orthoclinical- escarpment 4 types of slope based on the slope aspect to the bedding orientation. The sliding plane, or so call the failure plane, was identified by aero photo, field reconnaissance and verification, and DEM before and after the typhoon event. Colluvium material deposited on the slip plane was removed based on the scarp and foot position, mass movement pattern, weak plane orientation, and the micro topography of a landslide to achieve the reasonable sliding plane. The maximum depth of sliding surface is explored through the slope type and sliding plane in total of 276 landslide cases. Results demonstrate that the average maximum depth, Dam, of dip slope is 4.6 m, Dam of orthoclinical-dip, escarpment, and orthoclinical-escarpment slopes are 5.8, 6.0, and 6.3 m respectively. In general, Dam is creasing with the average slope of landslide, the relationship of both factor is achieved in the study. Meanwhile, the orthographic projection area of landslide is increasing with the slope angle till the angle up to 40 degree then decreasing. The depth also varies with landslide magnitude. Finally, the relation of the depth normal to slope surface and the depth in gravity direction of landslides in four types slope are proposed, the R square values are 0.862 to 0.891 showing a good correlation between two types of depth.

Modeling landslide runout dynamics and hazards: crucial effects of initial conditions

NASA Astrophysics Data System (ADS)

Iverson, R. M.; George, D. L.

2016-12-01

Physically based numerical models can provide useful tools for forecasting landslide runout and associated hazards, but only if the models employ initial conditions and parameter values that faithfully represent the states of geological materials on slopes. Many models assume that a landslide begins from a heap of granular material poised on a slope and held in check by an imaginary dam. A computer instruction instantaneously removes the dam, unleashing a modeled landslide that accelerates under the influence of a large force imbalance. Thus, an unrealistically large initial acceleration influences all subsequent modeled motion. By contrast, most natural landslides are triggered by small perturbations of statically balanced effective stress states, which are commonly caused by rainfall, snowmelt, or earthquakes. Landslide motion begins with an infinitesimal force imbalance and commensurately small acceleration. However, a small initial force imbalance can evolve into a much larger imbalance if feedback causes a reduction in resisting forces. A well-documented source of such feedback involves dilatancy coupled to pore-pressure evolution, which may either increase or decrease effective Coulomb friction—contingent on initial conditions. Landslide dynamics models that account for this feedback include our D-Claw model (Proc. Roy. Soc. Lon., Ser. A, 2014, doi: 10.1098/rspa.2013.0819 and doi:10.1098/rspa.2013.0820) and a similar model presented by Bouchut et al. (J. Fluid Mech., 2016, doi:10.1017/jfm.2016.417). We illustrate the crucial effects of initial conditions and dilatancy coupled to pore-pressure feedback by using D-Claw to perform simple test calculations and also by computing alternative behaviors of the well-documented Oso, Washington, and West Salt Creek, Colorado, landslides of 2014. We conclude that realistic initial conditions and feedbacks are essential elements in numerical models used to forecast landslide runout dynamics and hazards.

History and present state of the Slano Blato landslide

NASA Astrophysics Data System (ADS)

Logar, J.; Fifer Bizjak, K.; Kočevar, M.; Mikoš, M.; Ribičič, M.; Majes, B.

2005-06-01

The Slano Blato landslide is more than 1290m long, 60 to 200m wide and 3 to 11m deep with a volume of about 700000m3. It is located in the Eocene flysch region of western Slovenia with a limestone overthrust in the direct vicinity, above the landslide. The landslide moves mainly as a viscous earth flow with occurrences of rapid mud flows. In dry periods or in freezing conditions it behaves as a group of several slow to moderate landslides. The landslide follows the course of the Grajšček stream and is presently only 220m away from Lokavec village. The landslide was first mentioned about 200 years ago. In 1887 it flowed as a liquid flow and reached and destroyed the main road in the valley 2 km away. The Austro-Hungarian monarchy sent one engineer to the site and 17 years later the slide was remediated with a series of torrential check dams. The monarchy prohibited any construction works in the influence area of the landslide. During the 20th century the region changed from Austrian, Italian, Yugoslav, and finally to Slovenian government in 1991. The relevant Austrian measures and decisions were forgotten during the course of the years, and building permits were issued after the World War II to local people who populated the part of the landslide influence area. Simultaneously, regular maintenance of the excellent past engineering works was neglected. In November 2000 a large landslide of mud and debris was triggered again and it still presents a danger to the relatively new residential houses today. At present, the village is protected against mudflows by a small rockfill dam and by the regulation of the stream bed. In rainy periods removal of mud is necessary to maintain safe conditions for the village. The paper discusses the geological, hydrogeological, hydrological and geotechnical conditions for the occurrence of the Slano Blato landslide. The primary reasons for the Slano blato landslide are the geological and hydrogeological conditions just beneath the

Landslides - Cause and effect

USGS Publications Warehouse

Radbruch-Hall, D. H.; Varnes, D.J.

1976-01-01

Landslides can cause seismic disturbances; landslides can also result from seismic disturbances, and earthquake-induced slides have caused loss of life in many countries. Slides can cause disastrous flooding, particularly when landslide dams across streams are breached, and flooding may trigger slides. Slope movement in general is a major process of the geologic environment that places constraints on engineering development. In order to understand and foresee both the causes and effects of slope movement, studies must be made on a regional scale, at individual sites, and in the laboratory. Areal studies - some embracing entire countries - have shown that certain geologic conditions on slopes facilitate landsliding; these conditions include intensely sheared rocks; poorly consolidated, fine-grained clastic rocks; hard fractured rocks underlain by less resistant rocks; or loose accumulations of fine-grained surface debris. Field investigations as well as mathematical- and physical-model studies are increasing our understanding of the mechanism of slope movement in fractured rock, and assist in arriving at practical solutions to landslide problems related to all kinds of land development for human use. Progressive failure of slopes has been studied in both soil and rock mechanics. New procedures have been developed to evaluate earthquake response of embankments and slopes. The finite element method of analysis is being extensively used in the calculation of slope stability in rock broken by joints, faults, and other discontinuities. ?? 1976 International Association of Engineering Geology.

Landslide mobility and connectivity with fluvial networks during earthquakes

NASA Astrophysics Data System (ADS)

Clark, M. K.; West, A. J.; Li, G.; Roback, K.; Zekkos, D.

2016-12-01

In some tectonically active mountain belts, coseismic landslide events displace sediment volumes equal to long-term erosion rates when averaged over typical seismic cycles. However, the contribution of landsliding to total erosional budgets depends critically on the export of landslide debris, which in turn is thought to depend on connectivity of landslides with fluvial channels and the sediment transport capacity of fluvial systems. From the 2015 Mw7.8 Gorkha event in central Nepal, we present connectivity data based on a mapped inventory of nearly 25,000 landslides and compare these results to those from the 2008 Mw7.9 Wenchuan earthquake in China. Landslide runout length in Nepal scales with landslide volume, and has a strong association with slope, elevation and relief. Connectivity is greatest for larger landslides in the high-relief, high-elevation part of the High Himalaya, suggesting that these slope failures may have the most immediate impact on sediment dynamics and cascading hazards, such as landslide reactivation by monsoon rainfall and outburst floods that pose immediate threat to communities far down stream. Although more rare than landslides at lower elevation, large high-elevation landslides that cause outburst flooding due to failure of landslide dams in the upper reaches of large Himalayan rivers may also enhance river incision downstream. The overall high fluvial connectivity (i.e. high percentage of landslide volumes directly intersecting the stream network) of coseismic landsliding in the Gorkha event suggests coupling between the earthquake cycle and sediment/geochemical budgets of fluvial systems in the steep topography of the Himalaya.

Contemporary glacier retreat triggers a rapid landslide response, Great Aletsch Glacier, Switzerland

NASA Astrophysics Data System (ADS)

Kos, Andrew; Amann, Florian; Strozzi, Tazio; Delaloye, Reynald; Ruette, Jonas; Springman, Sarah

2016-12-01

The destabilization and catastrophic failure of landslides triggered by retreating glaciers is an expected outcome of global climate change and poses a significant threat to inhabitants of glaciated mountain valleys around the globe. Of particular importance are the formation of landslide-dammed lakes, outburst floods, and related sediment entrainment. Based on field observations and remote sensing of a deep-seated landslide, located at the present-day terminus of the Great Aletsch Glacier, we show that the spatiotemporal response of the landslide to glacier retreat is rapid, occurring within a decade. Our observations uniquely capture the critical period of increase in slope deformations, onset of failure, and show that measured displacements at the crown and toe regions of the landslide demonstrate a feedback mechanism between glacier ice reduction and response of the entire landslide body. These observations shed new light on the geomorphological processes of landslide response in paraglacial environments, which were previously understood to occur over significantly longer time periods.

Cosesimic landslides and their post-quake effects (Invited)

NASA Astrophysics Data System (ADS)

Huang, R.; Fan, X.

2013-12-01

On May 12, 2008, a devastating earthquake of magnitude Mw 7.9 hit China's Sichuan province. The quake, originating in the Longmen Shan fault zone at the eastern margin of Tibetan Plateau, was the country's largest seismic event in more than 50 years. It triggered more than 60,000 destructive landslides and 828 landslide dams over an area of 35,000 square kilometers, that caused about one third of the total fatalities. The combination of strong and long-lasting ground shaking, steep, rugged topography and a fragile and densely jointed lithology probably controlled the occurrence of landslides during the earthquake, but we found that other two factors (fault type and slip rate during the earthquake), may also have played a role. Landslides were clustered in a much wider corridor along the thrusting part of the Yingxiu-Beichuan fault than the strike-slip part. Large-scale landslides with an area of more than 50,000 m2 were concentrated where fault slip-rates were highest, near the intersections and junctures of individual segments of the fault. After the earthquake, debris flow hazard has become a significant concern. A tremendous amount of loose material from landslides that occurred during the earthquake is suspended on the hillslopes, ready to be eroded and transported by rain. More than 2000 occurrences of debris flow have been recorded by the Land and Resources Department of Sichuan Province following the 2008 quake till 2012. The threshold in hourly rainfall intensity for triggering debris flows was found to be around 60% lower after the earthquake than it had been before, according to the record in Beichuan. How long it will take for the debris flow frequency to return to pre-earthquake levels depends on a large number of factors, including rainfall intensity, natural re-vegetation and self-stabilization processes on slopes. We anticipate that - despite large uncertainties - debris flows that directly result from sediment movement during the 2008 earthquake may

Digital inventory of landslides and related deposits in Honduras triggered by Hurricane Mitch

USGS Publications Warehouse

Harp, Edwin L.; Hagaman, Kirk W.; Held, Matthew D.; McKenna, Jonathan P.

2002-01-01

Intense rainfall from Hurricane Mitch from October 27-31, 1998, exceeded 900 mm in places in Honduras and triggered in excess of 500,000 landslides throughout the country. Landslides damaged an estimated 70% of the road network in Honduras based on estimates by the U. S Army Corps of Engineers. Numbers of fatalities due to landslides are not accurately known due to the fact that numerous small villages throughout Honduras lost residents to landslides without an official count being recorded. A conservative estimate would place the number at near 1,000. Debris flows accounted for over 95% of the landslides and ranged in thickness from 1 to 15 m. Flow path lengths of these failures ranged from several meters to 7.5 km. The highest concentrations of debris flows occurred in the mountains near the town of Choluteca where over 900 mm of rain fell in three days. Although landslides other than debris flows were few, several deep-seated landslides in the city of Tegucigalpa severely impacted people and property. The 'El Berrinche' rotational slump/earth flow of approximately six million cubic meters volume destroyed the entire neighborhood of Colonia Soto near the center of the city. The landslide also dammed the Rio Choluteca and created a lagoon behind the landslide dam, which immediately posed a health problem for the city, because raw, untreated sewage was emptying into the Rio Choluteca. Several areas of highly concentrated landslides have been responsible for much of the flooding problem as well. Huge sediment influxes from landslide source areas near La Ceiba, La Libertad, Marale, and in several arms of El Cajon Reservoir have reduced stream capacities to practically nothing and have exacerbated flooding conditions in even the moderate rainfall seasons since Hurricane Mitch. The ongoing hazard to communities from landslides triggered during Hurricane Mitch are being analyzed using aerial photography taken by the U.S. Air Force and by supplemental photography taken

Environmental impact of the landslides caused by the 12 May 2008, Wenchuan, China earthquake

USGS Publications Warehouse

Highland, Lynn; Sun, Ping; Edited by Margottini, Claudio; Canuti, Paolo; Sassa, Kyoji

2013-01-01

The magnitude 7.9 (Mw) Wenchuan, China, earthquake of May 12, 2008 caused at least 88,000 deaths of which one third are estimated to be due to the more than 56,000 earthquake-induced landslides. The affected area is mountainous, featuring densely-vegetated, steep slopes through which narrowly confined rivers and streams flow. Numerous types of landslides occurred in the area, including rock avalanches, rock falls, translational and rotational slides, lateral spreads and debris flows. Some landslides mobilized hundreds of million cubic meters of material, often resulting in the damming of rivers and streams, impacting river ecosystems and morphology. Through an extensive search of both Chinese- and English-language publications we provide a summary of pertinent research on environmental effects, emphasizing key findings. Environmental effects caused by landslides include the alteration of agriculture, changes to natural ecosystems, changes in river morphology due to landslide dams and other effects such as sedimentation and flooding. Damage by landslides to the giant panda reserve infrastructure and habitat, was severe, threatening the survival of one of the world’s rarest species. The Panda reserves are of national significance to China, and to the vital tourism economy of the region. One of the major impacts to both the natural and built environment is the complete relocation of some human populations and infrastructure to new areas, resulting in the abandonment of towns and other areas that were damaged by the earthquake and landslides. The landslide effects have affected the biodiversity of the affected area, and it has been hypothesized that strict forest preservation measures taken in the years preceding the earthquake resulted in a reduction of the environmental damage to the area.

Structural controls on the large landslides triggered by the 14 November 2016, MW 7.8 Earthquake, Kaikoura, New Zealand

NASA Astrophysics Data System (ADS)

Massey, Chris

2017-04-01

The Kaikoura earthquake generated tens of thousands of landslides over a total area of about 10,000 km2, with the majority concentrated in a smaller area of about 3,500 km2. A noteworthy aspect of this event is the large number of landslides that occurred on the steep coastal cliffs south of Ward and extending to Oaro, north of Christchurch, which led to the closure of state highway routes. Another noteworthy feature of this earthquake is the large number (more than 190) of valley blocking landslides it generated. This was partly due to the presence of steep and confined slopes in areas of strong ground shaking. The largest valley blocking landslide has an approximate volume of 12(±2) M m3 and the debris travelled about 2.7 km down slope forming a dam on the Hapuku River. Given the sparse population in the vicinity of the landslides, only a few homes were impacted and there were no recorded deaths due to landslides. However, the long-term stability of cracked slopes and landslide "dams" from future strong earthquakes and significant rain events are an ongoing concern to central and local government agencies responsible for rebuilding homes and infrastructure. A particular concern is the potential for debris floods to affect downstream residences and infrastructure should some of the landslide dams breach catastrophically. The mapped landslide distribution reflects the complexity of the earthquake rupture—at least 13 faults ruptured to the ground surface or sea floor. The majority of landslides occurred in two geological and geotechnically distinct materials: Neogene sedimentary rocks (sandstones, limestones and siltstones) where first-time and reactivated rock-slides were the dominant landslide type, and Torlesse "basement" rocks (greywacke sandstones and argillite) where first-time rock and debris avalanches dominated. The largest landslides triggered by the earthquake are located either on or adjacent to faults that ruptured to the ground surface and so they

Assessment of Hazards Associated with the Bluegill Landslide, South-Central Idaho

USGS Publications Warehouse

Ellis, William L.; Schuster, Robert L.; Schulz, William H.

2004-01-01

The Bluegill landslide, located in south-central Idaho, is part of a larger landslide complex that forms an area the Salmon Falls Creek drainage named Sinking Canyon Recent movement of the Bluegill landslide, apparently beginning sometime in late 1998 or early 1999, has caused a 4.5 ha area of the canyon rim to drop as much as 8 m and move horizontally several meters into the canyon. Upward movement of the toe of the landslide in the bottom of canyon has created a dam that impounds a lake approximately 2 km in length. The landslide is on public administered by the U.S. Bureau of Land Management (BLM). As part of ongoing efforts to address possible public safety concerns, the BLM requested that the U.S. Geological Survey (USGS) conduct a preliminary hazard assessment of the landslide, examine possible mitigation options, and identify alternatives for further study and monitoring of the landslide. This report presents the findings of that assessment based on a field reconnaissance of the landslide on September 24, 2003, a review of data and information provided by BLM and researchers from Idaho State University, and information collected from other sources.

Landslides of Palestinian Region

NASA Astrophysics Data System (ADS)

Alwahsh, H.

2013-12-01

Natural disasters are extreme sudden events caused by environmental and natural actors that take away the lives of many thousands of people each year and damage large amount of properties. They strike anywhere on earth, often without any warning. A risk maps of natural disaster are very useful to identify the places that might be adversely affected in the event of natural disaster. The earthquakes are one of natural disaster that have the greatest hazards and will cause loss of life and properties due to damaging the structures of building, dams, bridges. In addition, it will affect local geology and soil conditions. The site effects play an important role in earthquake risk because of its amplification or damping simulation. Another parameter in developing risk map is landslide, which is also one of the most important topics in site effect hazards. Palestine region has been suffering landslide hazards because of the topographical and geological conditions of this region. Most Palestine consists of mountainous area, which has great steep slopes and the type of soil is mainly grayish to yellowish silty clay (Marl Soil). Due to the above mentioned factors many landslides have been occurred from Negev south to the northern borders of Palestine. An example of huge and destruction landslide in a Palestine authority is the landslide in the White Mountain area in the city of Nablus, which occurred in 1997. The geotechnical and geophysical investigation as well as slope stability analysis should be considered in making landslide maps that are necessary to develop risk levels of the natural disaster. Landslides occurred in slopes that are created naturally or by human beings. Failure of soil mass occurs, and hence landslide of soil mass happen due to sliding of soil mass along a plane or curved surface. In general, the slopes become unstable when the shear stresses (driving force) generated in the soil mass exceed the available shearing resistance on the rupture surface

Research on the resurrection evolution mechanism of Gendakan ancient landslide in the upstream on Lancang River, China

NASA Astrophysics Data System (ADS)

H, D.

2017-12-01

The Gendakan ancient landslide is located on the West bank of the upstream on Lancang River and about 4 km downstream from the Gushui hydropower station dam site. The ancient landslide is 850 m long and 700 m wide, the drill cores show that the maximum thickness of the landslide body is 107 m, with a mean thickness of approximately 80 m. Thus, the overall volume is about 3000×104m3. At present, the landslide has obvious deformation and failure signs, the leading edge is collapsing step by step. Once the landslide is unstable, it will affect the construction and operation of the Gushui hydropower station. In this paper, the development characteristics of the landslide accumulation body and the characteristics of the resurrection deformation are summarized in detail from the regional geological environment of the Gandakan landslide accumulation body. The three-dimensional geological model is established to analyze the stress and strain, displacement change and deformation failure characteristics and further evaluate its resurrection evolution trend , Combined with the developmental characteristics of the typical rock mass in the nearshore slope of the engineering area, analyzes the process of the resurrection and evolution of the rooted landslide accumulation. The FLAC-3D finite difference software was used to analyze the shear strain increment, displacement and plastic zone of the landslide accumulation body under natural conditions and rainfall conditions. The results show: the Gendakan landslide is stable in the natural state, and its deformation and failure are mainly caused by the tensile and shearing of the surface, under the rainfall condition, the local deformation and failure of the landslide accumulation body is obvious and the resurrection deformation Intensified. The resurrection evolutionary process of Gendakan ancient landslide includes three steps below. 1) The landslide body trailing edge creep cracking, leading edge shear deformation. 2) Sliding

Solid discharge and landslide activity at basin scale

NASA Astrophysics Data System (ADS)

Ardizzone, F.; Guzzetti, F.; Iadanza, C.; Rossi, M.; Spizzichino, D.; Trigila, A.

2012-04-01

This work presents a preliminary analysis aimed at understanding the relationship between landslide sediment supply and sediment yield at basin scale in central and southern Italy. A database of solid discharge measurements regarding 116 gauging stations, located along the Apennines chain in Italy, has been compiled by investigating the catalogues, named Annali Idrologici, published by Servizio Idrografico e Mareografico Italiano in the period from 1917 to 1997. The database records several information about the 116 gauging stations, and especially reports the sediment yield monthly measurements (103 ton) and the catchments area (km2). These data have been used to calculate the average solid yield and the normalized solid yield for each station in the observation period. The Italian Landslide Inventory (Progetto IFFI) has been used to obtained the size of the landslides, in order to estimate the landslide mobilization rates. The IFFI Project funded by the Italian Government is realized by ISPRA (Italian National Institute for Environmental Protection and Research - Geological Survey of Italy) in partnership with the 21 Regions and Self Governing Provinces. 21 of the 116 gauging stations and the related catchments have been selected on the basis of the length of the solid discharge observation period and excluding the catchments with dams located upstream the stations. The landslides inside the selected catchments have been extracted from the IFFI inventory, calculating the planimetric area of each landslide. Considering both the shallow and deep landslides, the landslide volume has been estimated using an empirical power law relation (landslide area vs. volume). The total landslide volume in the study areas and the average sediment yield measured at the gauging stations have been compared, analysing the behaviour of the basins which drainage towards the Tyrrhenian sea and the basins which drainage towards the Adriatic sea.

Numerical simulation of scouring-deposition variations caused by rainfall-induced landslides in the upstream of Zengwun River, Taiwan

NASA Astrophysics Data System (ADS)

Lee, Ming-Hsi; Liao, Yi-Wen; Tsai, Kuang-Jung

2017-04-01

In recent years, the increasing sediment disasters of severe rainfall-induced landslides on human lives and lifeline facilities worldwide have advanced the necessity to find out both economically acceptable and useful techniques to predict the occurrence and destructive power of the disasters. In August 2009, Typhoon Morakot brought a large amount of rainfall with both high intensity and long duration to a vast area of Taiwan. Unfortunately, this resulted in a catastrophic landslide in watershed of Zengwun-River reservoir, southern Taiwan. Meanwhile, large amounts of landslides were formed in the upstream of Zengwun River. The major scope of this study is to apply numerical model to simulate the scouring-deposition variations caused by rainfall-induced landslides that occurred in the upstream of Zengwun River during Typhoon Morakot. This study proposed the relation diagrams of the intermediate diameter (d50), recurrence interval (T) and scouring-deposition depth (D), and applied the diagrams to understand the impacts of the scouring-deposition variations on the structures for water and soil conservation and their measurements. Based on the simulation of scouring-deposition variation at the Da-Bu dam and Da-Bang dam, this study also discussed the scouring-deposition variations of different sections under different scenarios (including flow rate, intermediate diameters and structures). In summary, the result suggested that the diagrams of the intermediate diameter, recurrence interval and scouring-deposition depth could be used as the reference for designing the check dams, ground sills and lateral constructions.

Geomodels of coseismic landslides environments in Central Chile.

NASA Astrophysics Data System (ADS)

Serey, A.; Sepulveda, S. A.; Murphy, W.; Petley, D. N.

2017-12-01

these geomodels are a powerful tool for earthquake-induced landslide hazard assessment. As an implication we can identify landslide-prone areas, distinguish different seismic scenarios and describe related potential hazards, including burial and river damming by large rock slides and rock avalanches.

Recent extreme rainfall-induced landslides and government countermeasures in Korea

NASA Astrophysics Data System (ADS)

Lee, Su-Gon; Hencher, Stephen

2013-04-01

During 2011 a large number of landslides occurred in South Korea as a result of heavy rainfall (160~300mm/day) which fell between 19 June and 27 July. Fifty eight people were killed and 200 injured at 11 locations. Almost 80% of the fatal landslides can be attributed at least in part to human activities such as an army camp, pedestrian road, forest road, cemetery, tomb, irrigation for vegetable garden and fruit farm. This paper addresses the anthropogenic influences on recent landslides in Korea. In addition, this paper discusses the Korean government countermeasures related to landslides. Restoration works tends to start immediately without design reports and without investigating the causes of landslides. Restoration works tend to comprise simple erosion control such as hard-covering to failure surfaces and the provision of check dams. These measures are implemented without any input from specialist geotechnical engineers. Persons injured or subject to economic loss as a result of landslides have often taken legal action against the Korean government. The most usual result is that experts appointed by the courts side with Government and simply conclude that the disasters are the natural consequence of heavy rainfall. As a result claimants have generally lost their cases and received no compensation. Furthermore, because of the lack of proper investigations there are no lessons learned from past landslides and no department has been established within the Korean government, tasked with reducing landslide risk.

Seasonal deformation and active landslide thickness revealed by spaceborne InSAR observations: a case study of Crescent lake landslide, WA

NASA Astrophysics Data System (ADS)

Hu, X.; Lu, Z.; Pierson, T. C.; Kramer, R.

2017-12-01

landslides, glaciers, volcanos, dams, etc.

A review of the 2005 Kashmir earthquake-induced landslides; from a remote sensing prospective

NASA Astrophysics Data System (ADS)

Shafique, Muhammad; van der Meijde, Mark; Khan, M. Asif

2016-03-01

The 8th October 2005 Kashmir earthquake, in northern Pakistan has triggered thousands of landslides, which was the second major factor in the destruction of the build-up environment, after earthquake-induced ground shaking. Subsequent to the earthquake, several researchers from home and abroad applied a variety of remote sensing techniques, supported with field observations, to develop inventories of the earthquake-triggered landslides, analyzed their spatial distribution and subsequently developed landslide-susceptibility maps. Earthquake causative fault rupture, geology, anthropogenic activities and remote sensing derived topographic attributes were observed to have major influence on the spatial distribution of landslides. These were subsequently used to develop a landslide susceptibility map, thereby demarcating the areas prone to landsliding. Temporal studies monitoring the earthquake-induced landslides shows that the earthquake-induced landslides are stabilized, contrary to earlier belief, directly after the earthquake. The biggest landslide induced dam, as a result of the massive Hattian Bala landslide, is still posing a threat to the surrounding communities. It is observed that remote sensing data is effectively and efficiently used to assess the landslides triggered by the Kashmir earthquake, however, there is still a need of more research to understand the mechanism of intensity and distribution of landslides; and their continuous monitoring using remote sensing data at a regional scale. This paper, provides an overview of remote sensing and GIS applications, for the Kashmir-earthquake triggered landslides, derived outputs and discusses the lessons learnt, advantages, limitations and recommendations for future research.

Characteristics of Landslides Triggered by Mw 7.8 2015 Gorkha Earthquake

NASA Astrophysics Data System (ADS)

Dhital, Smriti

The Mw 7.8 Gorkha earthquake struck central Nepal on April 25, 2015 and brought about a huge loss of life and property. The quake was also responsible for the generation of a large number of landslides. They blocked highways, devastated villages, and temporarily dammed some rivers. About 14,670 landslips were triggered off by the main shock and its numerous large aftershocks. Among the detected failures, about 23% had an area greater than 100 m2. Since such failures can directly affect people's life and property, they are considered for further investigation in this study. A comparison of these coseismic landslides with the 29 historical failures reveals that these landslides slightly exceed in number from those expected for the peak ground acceleration observed due to these earthquakes. The landslides seem to be concentrated within the area of the fault rupture surface. About 90% of the detected landslips could be classified as earth falls. The areas having relatively soft rocks, such as slates, shales, schists and phyllites of the Lesser Himalaya, suffered from a greater number of failures. The landslides had a strong correlation with the peak ground acceleration and they also showed a positive correlation with some landslide-susceptible geological formations composing the study area.

Preliminary Assessment of Landslides Along the Florida River Downstream from Lemon Reservoir, La Plata County, Colorado

USGS Publications Warehouse

Schulz, William H.; Coe, Jeffrey A.; Ellis, William L.; Kibler, John D.

2006-01-01

Nearly two-dozen shallow landslides were active during spring 2005 on a hillside located along the east side of the Florida River about one kilometer downstream from Lemon Reservoir in La Plata County, southwestern Colorado. Landslides on the hillside directly threaten human safety, residential structures, a county roadway, utilities, and the Florida River, and indirectly threaten downstream areas and Lemon Dam. Most of the area where the landslides occurred was burned during the 2002 Missionary Ridge wildfire. We performed geologic mapping, subsurface exploration and sampling, radiocarbon dating, and shallow ground-water and ground-displacement monitoring to assess landslide activity. Active landslides during spring 2005 were as large as 35,000 m3 and confined to colluvium. Debris flows were mobilized from most of the landslides, were as large as 1,500 m3, and traveled as far as 250 m. Landslide activity was triggered by elevated ground-water pressures within the colluvium caused by infiltration of snowmelt. Landslide activity ceased as ground-water pressures dropped during the summer. Shallow landslides on the hillside appear to be much more likely following the Missionary Ridge fire because of the loss of tree root strength and evapotranspiration. We used monitoring data and observations to develop preliminary, approximate rainfall/snowmelt thresholds above which shallow landslide activity can be expected. Landslides triggered during spring 2005 occurred within a 1.97 x 107 m3 older landslide that extends, on average, about 40 m into bedrock. The south end of this older landslide appears to have experienced deep secondary landsliding. Radiocarbon dating of sediments at the head of the older landslide suggests that the landslide was active about 1,424-1,696 years ago. A relatively widespread wildfire may have preceded the older landslide, and the landslide may have occurred during a wetter time. The wetter climate and effects of the wildfire would likely have

Landslides and the Fault Surface Ruptures during the 2008 Wengchuan Earthquake, Sichuan, China

NASA Astrophysics Data System (ADS)

Chigira, M.; Xiyong, Wu; Takashi, Inokuchi; Gonghui, Wang

2009-04-01

landslides were controlled by the fault: Landslides moving normal to the fault ruptures were most prevailing probably due to the directivity of the seismic wave. The most common landslides were of carbonate rocks, which could be attributable to the decrease in shear strength because of its dissolution by subsurface water. Relatively shallow landslides were concentratedly induced on the slopes in the valley of the Mingjian River from Yinghsiuwa through Wengchan to Maoxian. These slopes seem to be the inner gorges (Kelsey, 1998), which are formed by the acceleration of erosion, leading to the destabilization of valley slopes (Chigira, 2006). The inner valleys are as steep as 35 to 40 degrees with about 500 m height. Largest landslide in the history occurred in the middle of the affected area. It was 1.3 km wide and 5 km long with an area of 7 million m2 and its volume may be 1 billion m3 from the images of the satellite ALOS. This landslide was preceded by gravitational deformation, which was represented by a ridge-top depression. More than 30 landslide dams were made; dams consisting of large carbonate rubbles apparently stable and dams consisting of weathered marlstone or phyllite less stable.

Characterization of the Jure (Sindhupalchok, Nepal) Landslide by TLS and field investigations

NASA Astrophysics Data System (ADS)

Jaboyedoff, Michel; Leibundgut, Geoffroy; Penna, Ivanna; Dahal, Ranjan Kumar; Sevkota, Sanjaya; Sudmeier, Karen

2015-04-01

On August 2nd 2014, a huge rockslide of approximately 5 million m3 blocked the Sun-Koshi River upstream of Jure village (Northeast of Kathmandu, Nepal). This landslide killed approximately 155 people, destroying approximately 120 houses completely and 37 partially. The main road leading to China was cut and the Sun-Koshi hydropower plant was affected. The landslide dammed the river, creating a 2 km long lake. During the whole month of August the authorities and the army managed to drain the lake in order to avoid a potential dam collapse and a disaster by flooding downstream. In addition, a road was built very quickly in the opposite slope of the rockslide. The main road was reopened in November 2014 crossing the rock avalanche deposit to reach China border. Rocky steep slope on right bank of lake is used for earthen road construction. After the quick draining of the lake water on October 5, 2014, many landslides were induced or reactivated on the slopes along the lake shore. Some are affecting the slopes over several hundred in uphill section. However, the roads are also promoting shallow landslides or old landslides reactivation. The DEM extracted from merging 16 terrestrial laser scanner (TLS) acquisitions permits to analyse the rock fall avalanche volume, scar structure and deposits. The rockslide was developed in phyllites, quartzite and sandstones. The stratification is folded but mainly subhorizontal in the scar area, while the scar is defined by several faults and visible joint sets. Using TLS and SRTM data the volume of the rockslide can be approximated at 5 million m3. From TLS data it is also possible to identify regional faults, which form the back scar with a dip of approximately 165°/60°. The discontinuity sets ~250°/60° and 075°/45° are forming oblique shallow wedges. In addition, subvertical joints which are cutting the whole scar are oriented north 145°. All these structures permits to define the volume involved in the rockslide. Satellite

Site investigation and modelling at "La Maina" landslide (Carnian Alps, Italy)

NASA Astrophysics Data System (ADS)

Marcato, G.; Mantovani, M.; Pasuto, A.; Silvano, S.; Tagliavini, F.; Zabuski, L.; Zannoni, A.

2006-01-01

The Sauris reservoir is a hydroelectric basin closed downstream by a 136 m high, double arc concrete dam. The dam is firmly anchored to a consistent rock (Dolomia dello Schlern), but the Lower Triassic clayey formations, cropping out especially in the lower part of the slopes, have made the whole catchment basin increasingly prone to landslides. In recent years, the "La Maina landslide" has opened up several joints over a surface of about 100 000 m2, displacing about 1 500 000 m3 of material. Particular attention is now being given to the evolution of the instability area, as the reservoir is located at the foot of the landslide. Under the commission of the Regional Authority for Civil Protection a numerical modelling simulation in a pseudo-time condition of the slope was developed, in order to understand the risk for transport infrastructures, for some houses and for the reservoir and to take urgent mesaures to stabilize the slope. A monitoring system consisting of four inclinometers, three wire extensometers and ten GPS bench-mark pillars was immediately set up to check on surface and deep displacements. The data collected and the geological and geomorphological evidences was used to carry out a numerical simulation. The reliability of the results was checked by comparing the model with the morphological evidence of the movement. The mitigation measures were designed and realised following the indications provided by the model.

Landslide activity as a threat to infrastructure in river valleys - An example from outer Western Carpathians (Poland)

NASA Astrophysics Data System (ADS)

Łuszczyńska, Katarzyna; Wistuba, Małgorzata; Malik, Ireneusz

2017-11-01

Intensive development of the area of Polish Carpathians increases the scale of landslide risk. Thus detecting landslide hazards and risks became important issue for spatial planning in the area. We applied dendrochronological methods and GIS analysis for better understanding of landslide activity and related hazards in the test area (3,75 km2): Salomonka valley and nearby slopes in the Beskid Żywiecki Mts., Outer Western Carpathians, southern Poland. We applied eccentricity index of radial growth of trees to date past landslide events. Dendrochronological results allowed us to determine the mean frequency of landsliding at each sampling point which were next interpolated into a map of landslide hazard. In total we took samples at 46 points. In each point we sampled 3 coniferous trees. Landslide hazard map shows a medium (23 sampling points) and low (20 sampling points) level of landslide activity for most of the area. The highest level of activity was recorded for the largest landslide. Results of the dendrochronological study suggest that all landslides reaching downslope to Salomonka valley floor are active. LiDAR-based analysis of relief shows that there is an active coupling between those landslides and river channel. Thus channel damming and formation of an episodic lake are probable. The hazard of flooding valley floor upstream of active landslides should be included in the local spatial planning system and crisis management system.

Study on seepage characteristics of inclined wall dam after heavy drought

NASA Astrophysics Data System (ADS)

Wei, YE; Fuheng, MA

2018-05-01

For seepage of the dam slope with cracks after drought, there are two methods to study including the physical model test and numerical calculation. However, the physical model test can not visualize the seepage field in the dam body intuitively, and the mathematical model is not accurate because of the precision of the parameter. So in this paper, combined physical model with mathematical model, the surface crack development on the dam slope and the changes of pore water pressure were studied through the physical model test, and then numerical calculation was carried out to analyze the internal seepage of the dam body. The results showed that cracks were more likely to develop at middle of the upstream dam slope and dam heel, and cracks for different degrees appeared at different parts of the dam slope after drought. The development of cracks provided a preferential permeable channel which caused that the area near the crack was easily to become saturated. The saturated zone kept expanding leading the infiltration line to be close to the transition layer and the infiltration line was no longer a smooth curve. There were seepage damages and landslide hazards existing with such seepage characteristics, which would threaten the safety of the dam.

An overview of recent large landslides in northern British Columbia, Canada.

NASA Astrophysics Data System (ADS)

Geertsema, M.; Clague, J. J.; Schwab, J. W.; Evans, S. G.

2003-04-01

Within the last few decades, at least twenty-four, long-runout rapid landslides, each in excess of 1 million m^3, have occurred in northern British Columbia. Fifteen of the landslides have happened within the last 10 years alone. The landslides include low- gradient rapid flowslides in cohesive sediments, rock avalanches, and complex rock slide - flowslides and rock slide - debris flows. The flowslides have occurred in a variety of sediments, including glaciolacustrine deposits, clay-rich tills, and clay-rich colluvium. The rock failures have involved weak shales overlain by sandstone, and volcanic rocks. We are cataloguing these landslides in a compendium of natural hazards for northern British Columbia. Pre- and post-landslide aerial photographs have been obtained for fifteen of the landslides, and detailed topographic maps have been generated from these photographs. In addition we have determined soil properties, including Atterberg tests for six of the flowslides. The rock avalanches occur in three types of settings: (1) dip slopes in sedimentary rocks in the Rocky Mountain foothills; (2) escarpments of flat-lying sedimentary rocks where spreading is happening; and (3) unstable cirque walls. Infrastructure and resources at risk from these types of large landslides include settlements, forest roads and highways, pipelines, fish habitat, forests, and farmland. One rock avalanche terminated within 2 km of the Alaska Highway, and a rock slide came within a few kilometres of a farm house. Most of these landslides have impounded streams or rivers, thus the hazard associated with upstream inundation and catastrophic dam failure must also be considered. There appears to be an increase in the frequency of large landslides in northern British Columbia. Is this due to climate change? Can we expect this trend to continue?

Prediction of Rainfall-Induced Landslides

NASA Astrophysics Data System (ADS)

Nadim, F.; Sandersen, F.

2009-12-01

Rainfall-induced landslides can be triggered by two main mechanisms: shear failure due to build-up of pore water pressure and erosion by surface water runoff when flow velocity exceeds a critical value. Field measurements indicate that, in the initial phase, the slip surface of a landslide often occurs along the top of a relatively impermeable layer located at some depth within the soil profile, e.g. at the contact with a shallow underlying bedrock or parent rock. The shear strength along this surface and hence the stability of the slope is governed by the pore water pressure. The pore pressure is in turn controlled by water seepage through the slope, either from infiltrated rain, or from groundwater that follows bedrock joints and soil layers with high permeability. When the infiltration rate of the underlying layer is too low for further downward penetration of water or when a wetting front is produced, pore water pressure builds up, reducing the soil shear strength. During high intensity rainfall, surface water runoff will exert shear stresses on the bed material. De-pending on the grain size distribution and specific gravity of the material, erosion might occur when the flow velocity exceeds a critical value. As erosion progresses and sediment concentration increases, the flow regime may become unstable with heavy erosion at high flow velocity locations triggering a debris flow. In many cases, previous landslides along steep gully walls have fed an abundance of loose soil material into the gullies. Landslides along gully walls that obstruct the water transport may also trigger debris flows when the landslide-dam collapses, creating a surge downstream. Both the long-duration (1 or more days) and short-duration precipitation (of the order of 1 hour) are significant in the triggering of shallow landslides, since the critical short-duration rainfall intensity reduces as the antecedent accumulated rainfall increases. Experiences in Norway indicate that the maxi

Sunkoshi landslide in Nepal and its possible impact in India: A remote sensing based appraisal

NASA Astrophysics Data System (ADS)

Champati ray, P. K.; Chattoraj, S. L.

2014-12-01

A devastating landslide that killed at least 156 people occurred on the right bank of Sunkoshi river at village Jure, 70 km northeast of Kathmandu in Nepal. It not only affected hydroelectric projects in the near vicinity but also had potential to flood large tracts of downstream area in Nepal and north Bihar. Timely action by Nepal Army and Indian authorities have averted a major disaster but satellite data analysis (using IRS Resourcesat-2 LISS IV, WorldView-2, RISAT-1, Radarsat-2 etc.) reveal that the site was easily identifiable on satellite image as a potential landslide zone that has been affected by landslide related mass wasting in the past. It was reactivated and intermittently slided during 2000-2012 and finally when the whole mass came down on 2nd August 2014 pushing materials up to the opposite slope, a landslide dammed lake was formed on Sunkoshi river which extended up to a distance of 2.5-3 km as observed on 5-6th August on satellite images and the volume was estimated to be around 8.26-10.5 MCM, which needs to be released safely to avert any further disaster. Attempt is made to simulate the event to assess the run out and debris thickness using process based model. Satellite observation (using IRS Resourcesat-2 LISS IV, WorldView-2, RISAT-1, Radarsat-2 etc.), aided by hydrological data obtained through telemetry immensely helped to assess the landslide dimension, lake extent, volume, discharge, water level and travel time of water in Sunkoshi river. But the question remains how to manage the large amount of debris that Sunkoshi brings to its downstream areas causing river aggradations that eventually increases the flood risk. In such situations, the most immediate landslide remedial measures are four fold: monitoring of landslide, dam and reservoir using remote sensing and hydrological observations, controlled release of water, water discharge management at Kosi barrage and mechanism/preparedness for evacuation. The Sunkoshi landslide has brought to

The 22 March 2014 Oso Landslide, Snohomish County, Washington: Findings of the GEER Reconnaissance Investigation

NASA Astrophysics Data System (ADS)

Wartman, J.; Keaton, J. R.; Scott, A.; Benoit, J.; delaChapelle, J.; Gilbert, R.; Montgomery, D. R.

2014-12-01

. The second stage occurred in response to the unloading and the redirection of stresses within the landslide mass. We additionally approximated the risk for fatalities due to landslides in the region and found that it to be relatively high compared to guidelines for landslides in other developed countries and for large dams in the U.S.

Interactive Teaching about Landslides and Triggered Landslide Events

NASA Astrophysics Data System (ADS)

Taylor, Faith E.; Malamud, Bruce D.

2015-04-01

When we think of a landslide (mass wasting), both the public and scientists often envisage an individual movement of earth material down a slope. Yet, landslides often occur not as individuals, but as parts of a triggered landslide event. This is where a trigger (e.g., an earthquake or heavy rainfall) results in up to tens of thousands of landslides in a region in the minutes to days after the trigger. The sum of the impacts of these landslides may be greater than individual parts. This interactive Prezi poster will present ideas for innovative demonstrations, teaching practicals and projects, ranging from low-cost low-tech to more advanced digital methods, to communicate the ideas of landslides and triggered landslide events to the public and students. We will give live hands-on demonstrations and welcome discussions with other scientists to share ideas and best practices. This paper is aimed at those in secondary school/university education and the public sector looking for examples to interest and inform their respective audiences about landslides, triggered landslide events, and the importance and implications of considering landslides not just as individuals, but as populations.

Landslide-Generated Tsunami Model for Quick Hazard Assessment

NASA Astrophysics Data System (ADS)

Franz, M.; Rudaz, B.; Locat, J.; Jaboyedoff, M.; Podladchikov, Y.

2015-12-01

Alpine regions are likely to be areas at risk regarding to landslide-induced tsunamis, because of the proximity between lakes and potential instabilities and due to the concentration of the population in valleys and on the lakes shores. In particular, dam lakes are often surrounded by steep slopes and frequently affect the stability of the banks. In order to assess comprehensively this phenomenon together with the induced risks, we have developed a 2.5D numerical model which aims to simulate the propagation of the landslide, the generation and the propagation of the wave and eventually the spread on the shores or the associated downstream flow. To perform this task, the process is done in three steps. Firstly, the geometry of the sliding mass is constructed using the Sloping Local Base Level (SLBL) concept. Secondly, the propagation of this volume is performed using a model based on viscous flow equations. Finally, the wave generation and its propagation are simulated using the shallow water equations stabilized by the Lax-Friedrichs scheme. The transition between wet and dry bed is performed by the combination of the two latter sets of equations. The proper behavior of our model is demonstrated by; (1) numerical tests from Toro (2001), and (2) by comparison with a real event where the horizontal run-up distance is known (Nicolet landslide, Quebec, Canada). The model is of particular interest due to its ability to perform quickly the 2.5D geometric model of the landslide, the tsunami simulation and, consequently, the hazard assessment.

Landslide Buries Valley of the Geysers

NASA Technical Reports Server (NTRS)

2007-01-01

Geysers are a rare natural phenomena found only in a few places, such as New Zealand, Iceland, the United States (Yellowstone National Park), and on Russia's far eastern Kamchatka Peninsula. On June 3, 2007, one of these rare geyser fields was severely damaged when a landslide rolled through Russia's Valley of the Geysers. The landslide--a mix of mud, melting snow, trees, and boulders--tore a scar on the land and buried a number of geysers, thermal pools, and waterfalls in the valley. It also blocked the Geyser River, causing a new thermal lake to pool upstream. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this infrared-enhanced image on June 11, 2007, a week after the slide. The image shows the valley, the landslide, and the new thermal lake. Even in mid-June, just days from the start of summer, the landscape is generally covered in snow, though the geologically heated valley is relatively snow free. The tree-covered hills are red (the color of vegetation in this false-color treatment), providing a strong contrast to the aquamarine water and the gray-brown slide. According to the Russian News and Information Agency (RIA) [English language], the slide left a path roughly a kilometer and a half (one mile) long and 200 meters (600 feet) wide. Within hours of the landslide, the water in the new lake inundated a number of additional geysers. The geysers directly buried under the landslide now lie under as much as 60 meters (180 feet) of material, according to RIA reports. It is unlikely that the geysers will be able to force a new opening through this thick layer, adds RIA. Among those directly buried is Pervenets (Firstborn), the first geyser found in the valley, in 1941. Other geysers, such as the Bolshoi (Greater) and Maly (Lesser) Geysers, were silenced when buried by water building up behind the new natural dam. According to Vladimir and Andrei Leonov of the Russian Federation Institute of

Energy dissipation by submarine obstacles during landslide impact on reservoir - potentially avoiding catastrophic dam collapse

NASA Astrophysics Data System (ADS)

Kafle, Jeevan; Kattel, Parameshwari; Mergili, Martin; Fischer, Jan-Thomas; Tuladhar, Bhadra Man; Pudasaini, Shiva P.

2017-04-01

Dense geophysical mass flows such as landslides, debris flows and debris avalanches may generate super tsunami waves as they impact water bodies such as the sea, hydraulic reservoirs or mountain lakes. Here, we apply a comprehensive and general two-phase, physical-mathematical mass flow model (Pudasaini, 2012) that consists of non-linear and hyperbolic-parabolic partial differential equations for mass and momentum balances, and present novel, high-resolution simulation results for two-phase flows, as a mixture of solid grains and viscous fluid, impacting fluid reservoirs with obstacles. The simulations demonstrate that due to the presence of different obstacles in the water body, the intense flow-obstacle-interaction dramatically reduces the flow momentum resulting in the rapid energy dissipation around the obstacles. With the increase of obstacle height overtopping decreases but, the deflection and capturing (holding) of solid mass increases. In addition, the submarine solid mass is captured by the multiple obstacles and the moving mass decreases both in amount and speed as each obstacle causes the flow to deflect into two streams and also captures a portion of it. This results in distinct tsunami and submarine flow dynamics with multiple surface water and submarine debris waves. This novel approach can be implemented in open source GIS modelling framework r.avaflow, and be applied in hazard mitigation, prevention and relevant engineering or environmental tasks. This might be in particular for process chains, such as debris impacts in lakes and subsequent overtopping. So, as the complex flow-obstacle-interactions strongly and simultaneously dissipate huge energy at impact such installations potentially avoid great threat against the integrity of the dam. References: Pudasaini, S. P. (2012): A general two-phase debris flow model. J. Geophys. Res. 117, F03010, doi: 10.1029/ 2011JF002186.

Assessment of runout path and deposition area of potential landslide in Lushan Settlement, Central Taiwan

NASA Astrophysics Data System (ADS)

Tung, Ying-Hung; Hu, Jyr-Ching

2017-04-01

Our study focused on the Lushan Settlement, located in the slate belt of Central Range in Taiwan. We adopted L-band ALOS SAR data to generate the line of sight (LOS) velocities in study area using PS-InSAR technique constrained by continuous GPS data in the period from 2007 to 2010. The result revealed a subsidence rate in LOS up to -15 mm/yr. In addition, the borehole inclinometers, installed by Central Geological Survey, recorded a slip depth more than 120 m just in the northeastern of the village. Based on the results of PS-InSAR, records of inclinometers and field geological study, we adopt 2-D and 3-D numerical simulations by using Particle Flow Code to investigate scenario-based runout paths, particle velocities and landslide-affected area, which are useful information for decision support and future landslide hazard assessment. We analyzed different scenarios based on a dipping of the potential sliding surface varying from 20 to 5 degree. In each scenario, sliding of the unstable slope with a high frictional coefficient of the subsurface implied that the sliding surface of this creeping slope has still been developing. Furthermore, with 3-dimentaion models we analyzed the runout paths of rock mass, velocities of movement, and catastrophic landslide-impact area in the scenario that once the sliding surface fully develops or shear failure happens. Generally, the total runout distance could be more than 400 m, and the largest debris thickness might reach 100 m. Because of a low dipping angle of the sliding surface, the movement could last several minutes with a maxima velocity about 2 m/s. Moreover, a landslide-dam will form and capacity of dam could be predicted. In the worst case, the settlement, which is on the slope crown, might be destroyed and buried by debris.

Landslide inventories: The essential part of seismic landslide hazard analyses

USGS Publications Warehouse

Harp, E.L.; Keefer, D.K.; Sato, H.P.; Yagi, H.

2011-01-01

A detailed and accurate landslide inventory is an essential part of seismic landslide hazard analysis. An ideal inventory would cover the entire area affected by an earthquake and include all of the landslides that are possible to detect down to sizes of 1-5. m in length. The landslides must also be located accurately and mapped as polygons depicting their true shapes. Such mapped landslide distributions can then be used to perform seismic landslide hazard analysis and other quantitative analyses. Detailed inventory maps of landslide triggered by earthquakes began in the early 1960s with the use of aerial photography. In recent years, advances in technology have resulted in the accessibility of satellite imagery with sufficiently high resolution to identify and map all but the smallest of landslides triggered by a seismic event. With this ability to view any area of the globe, we can acquire imagery for any earthquake that triggers significant numbers of landslides. However, a common problem of incomplete coverage of the full distributions of landslides has emerged along with the advent of high resolution satellite imagery. ?? 2010.

Innovative Techniques for Teaching about Landslides and Triggered Landslide Events

NASA Astrophysics Data System (ADS)

Taylor, F. E.; Malamud, B. D.

2014-12-01

When we think of a landslide (mass wasting), both the public and scientists often envisage an individual movement of earth material down a slope. Yet, landslides often occur not as individuals, but as parts of a triggered landslide event. This is where a trigger (e.g., an earthquake or heavy rainfall) results in up to tens of thousands of landslides in a region in the minutes to days after the trigger. In this paper, we will present ideas for innovative demonstrations, teaching practicals and projects, ranging from low-cost low-tech to more advanced digital methods, to communicate the ideas of landslides and triggered landslide events to the public and students. This paper is aimed at those in secondary school/university education and the public sector looking for examples to interest and inform their respective audiences about landslides, triggered landslide events, and the importance and implications of considering landslides not just as individuals, but as populations.

Propagation of landslide inventory errors on data driven landslide susceptibility models

NASA Astrophysics Data System (ADS)

Henriques, C. S.; Zezere, J. L.; Neves, M.; Garcia, R. A. C.; Oliveira, S. C.; Piedade, A.

2009-04-01

Research on landslide susceptibility assessment developed recently worldwide has shown that quality and reliability of modelling results are more sensitive to the quality and consistence of the cartographic database than to statistical tools used in the modelling process. Particularly, the quality of the landslide inventory is of crucial importance, because data-driven models used for landside susceptibility evaluation are based on the spatial correlation between past landslide occurrences and a data set of thematic layers representing independent landslide predisposing factors. Uncertainty within landslide inventorying may be very high and is usually related to: (i) the geological and geomorphological complexity of the study area; (ii) the dominant land use and the rhythm and magnitude of land use change; (iii) the conservation level of landslide evidences (e.g., topography, vegetation, drainage) both in the field and aerial photographs; and (iv) the experience of the geomorphologist(s) that build the landslide inventory. Traditionally, landslide inventory has been made through aerial-photo interpretation and field work surveying by using standard geomorphological techniques. More recently, the interpretation of detailed geo-referenced digital ortophotomaps (pixel = 0.5 m), combined with the accurate topography, as become an additional analytical tool for landslide identification at the regional scale. The present study was performed in a test site (256 km2) within Caldas da Rainha County, located in the central part of Portugal. Detailed geo-referenced digital ortophotomaps obtained in 2004 were used to build three different landslide inventories. The landslide inventory #1 was constructed by a single regular trained geomorphologist using photo-interpretation. 408 probable slope movements were identified and geo-referenced by a point marked in the central part of the probable landslide rupture zone. The landslide inventory #2 was obtained through the examination

Neotectonics of the Vajont dam site

NASA Astrophysics Data System (ADS)

Mantovani, Franco; Vita-Finzi, Claudio

2003-08-01

The disastrous Vajont landslide (NE Italy) of 9 October 1963 is generally thought to have occurred on an existing failure surface. Reassessment of the morphological and structural evidence suggests that movement was on a normal fault plane which had juxtaposed Cretaceous limestone and highly fractured rock debris, thus rendering the dam site unusually susceptible to massive sliding. The proposed fault is consistent in strike with the regional lineament pattern. Although movement was triggered by the combined effects of heavy rainfall and changes in reservoir level, there is circumstantial evidence that seismicity played a contributory part in mobilising the slide by increasing pore pressure at the base of the slide as well as by any associated shaking.

Landslide databases for applied landslide impact research: the example of the landslide database for the Federal Republic of Germany

NASA Astrophysics Data System (ADS)

Damm, Bodo; Klose, Martin

2014-05-01

This contribution presents an initiative to develop a national landslide database for the Federal Republic of Germany. It highlights structure and contents of the landslide database and outlines its major data sources and the strategy of information retrieval. Furthermore, the contribution exemplifies the database potentials in applied landslide impact research, including statistics of landslide damage, repair, and mitigation. The landslide database offers due to systematic regional data compilation a differentiated data pool of more than 5,000 data sets and over 13,000 single data files. It dates back to 1137 AD and covers landslide sites throughout Germany. In seven main data blocks, the landslide database stores besides information on landslide types, dimensions, and processes, additional data on soil and bedrock properties, geomorphometry, and climatic or other major triggering events. A peculiarity of this landslide database is its storage of data sets on land use effects, damage impacts, hazard mitigation, and landslide costs. Compilation of landslide data is based on a two-tier strategy of data collection. The first step of information retrieval includes systematic web content mining and exploration of online archives of emergency agencies, fire and police departments, and news organizations. Using web and RSS feeds and soon also a focused web crawler, this enables effective nationwide data collection for recent landslides. On the basis of this information, in-depth data mining is performed to deepen and diversify the data pool in key landslide areas. This enables to gather detailed landslide information from, amongst others, agency records, geotechnical reports, climate statistics, maps, and satellite imagery. Landslide data is extracted from these information sources using a mix of methods, including statistical techniques, imagery analysis, and qualitative text interpretation. The landslide database is currently migrated to a spatial database system

Landslide seismic magnitude

NASA Astrophysics Data System (ADS)

Lin, C. H.; Jan, J. C.; Pu, H. C.; Tu, Y.; Chen, C. C.; Wu, Y. M.

2015-11-01

Landslides have become one of the most deadly natural disasters on earth, not only due to a significant increase in extreme climate change caused by global warming, but also rapid economic development in topographic relief areas. How to detect landslides using a real-time system has become an important question for reducing possible landslide impacts on human society. However, traditional detection of landslides, either through direct surveys in the field or remote sensing images obtained via aircraft or satellites, is highly time consuming. Here we analyze very long period seismic signals (20-50 s) generated by large landslides such as Typhoon Morakot, which passed though Taiwan in August 2009. In addition to successfully locating 109 large landslides, we define landslide seismic magnitude based on an empirical formula: Lm = log ⁡ (A) + 0.55 log ⁡ (Δ) + 2.44, where A is the maximum displacement (μm) recorded at one seismic station and Δ is its distance (km) from the landslide. We conclude that both the location and seismic magnitude of large landslides can be rapidly estimated from broadband seismic networks for both academic and applied purposes, similar to earthquake monitoring. We suggest a real-time algorithm be set up for routine monitoring of landslides in places where they pose a frequent threat.

Landslides triggered by Hurricane Mitch in Guatemala -- inventory and discussion

USGS Publications Warehouse

Bucknam, Robert C.; Coe, Jeffrey A.; Chavarria, Manuel Mota; Godt, Jonathan W.; Tarr, Arthur C.; Bradley, Lee-Ann; Rafferty, Sharon A.; Hancock, Dean; Dart, Richard L.; Johnson, Margo L.

2001-01-01

Upper Polochic valley and surrounding highlands and in the central Sierra de las Minas. The lower rainfall amounts (200 mm to 400 mm) occurred in the hills surrounding La Union, the eastern Sierra de las Minas, and in the border region with Honduras. In general, the rainfall received in these areas is roughly equivalent to the average precipitation received in a 1-year period. We used 10-m digital elevation models (DEMs) generated from contours on two quadrangles in the central Sierra de las Minas to create a map showing areas that were susceptible to landslides during Hurricane Mitch. To create the Hurricane Mitch susceptibility map, we developed a susceptibility threshold equation based on elevation and gradient. The analysis indicates that, at least on two quadrangles, gradients less than 9? were not susceptible to landslides during Hurricane Mitch. The slope of the line defined by the threshold equation indicates that less rainfall was required to initiate landslides on steep gradients than on shallow gradients. Ninety percent of the mapped landslides that were triggered by Hurricane Mitch are within the susceptible zone shown on the map. Eightysix percent of landslides that were mapped as predating Hurricane Mitch, and all landslides mapped as postdating Hurricane Mitch, are within the susceptible zone. We used LAHARZ software to model the potential downstream area affected by debris if a large landslide dam on the Rio La Lima were to fail. The model shows that the area affected would be similar to the area that was affected by a debris flow that mobilized from a large landslide along the Rio La Lima during Hurricane Mitch. The characteristics of rainfall-triggered landslides described in this report can be used as a partial guide to future landslide activity triggered by rainstorms. On the basis of existing data, hazardous areas include: moderate to steep hillslopes and

Improving Landslide Susceptibility Modeling Using an Empirical Threshold Scheme for Excluding Landslide Deposition

NASA Astrophysics Data System (ADS)

Tsai, F.; Lai, J. S.; Chiang, S. H.

2015-12-01

Landslides are frequently triggered by typhoons and earthquakes in Taiwan, causing serious economic losses and human casualties. Remotely sensed images and geo-spatial data consisting of land-cover and environmental information have been widely used for producing landslide inventories and causative factors for slope stability analysis. Landslide susceptibility, on the other hand, can represent the spatial likelihood of landslide occurrence and is an important basis for landslide risk assessment. As multi-temporal satellite images become popular and affordable, they are commonly used to generate landslide inventories for subsequent analysis. However, it is usually difficult to distinguish different landslide sub-regions (scarp, debris flow, deposition etc.) directly from remote sensing imagery. Consequently, the extracted landslide extents using image-based visual interpretation and automatic detections may contain many depositions that may reduce the fidelity of the landslide susceptibility model. This study developed an empirical thresholding scheme based on terrain characteristics for eliminating depositions from detected landslide areas to improve landslide susceptibility modeling. In this study, Bayesian network classifier is utilized to build a landslide susceptibility model and to predict sequent rainfall-induced shallow landslides in the Shimen reservoir watershed located in northern Taiwan. Eleven causative factors are considered, including terrain slope, aspect, curvature, elevation, geology, land-use, NDVI, soil, distance to fault, river and road. Landslide areas detected using satellite images acquired before and after eight typhoons between 2004 to 2008 are collected as the main inventory for training and verification. In the analysis, previous landslide events are used as training data to predict the samples of the next event. The results are then compared with recorded landslide areas in the inventory to evaluate the accuracy. Experimental results

Landslide susceptibility and early warning model for shallow landslide in Taiwan

NASA Astrophysics Data System (ADS)

Huang, Chun-Ming; Wei, Lun-Wei; Chi, Chun-Chi; Chang, Kan-Tsun; Lee, Chyi-Tyi

2017-04-01

This study aims to development a regional susceptibility model and warning threshold as well as the establishment of early warning system in order to prevent and reduce the losses caused by rainfall-induced shallow landslides in Taiwan. For the purpose of practical application, Taiwan is divided into nearly 185,000 slope units. The susceptibility and warning threshold of each slope unit were analyzed as basic information for disaster prevention. The geological characteristics, mechanism and the occurrence time of landslides were recorded for more than 900 cases through field investigation and interview of residents in order to discuss the relationship between landslides and rainfall. Logistic regression analysis was performed to evaluate the landslide susceptibility and an I3-R24 rainfall threshold model was proposed for the early warning of landslides. The validations of recent landslide cases show that the model was suitable for the warning of regional shallow landslide and most of the cases can be warned 3 to 6 hours in advanced. We also propose a slope unit area weighted method to establish local rainfall threshold on landslide for vulnerable villages in order to improve the practical application. Validations of the local rainfall threshold also show a good agreement to the occurrence time reported by newspapers. Finally, a web based "Rainfall-induced Landslide Early Warning System" is built and connected to real-time radar rainfall data so that landslide real-time warning can be achieved. Keywords: landslide, susceptibility analysis, rainfall threshold

Seismology-based early identification of dam-formation landquake events.

PubMed

Chao, Wei-An; Zhao, Li; Chen, Su-Chin; Wu, Yih-Min; Chen, Chi-Hsuan; Huang, Hsin-Hua

2016-01-12

Flooding resulting from the bursting of dams formed by landquake events such as rock avalanches, landslides and debris flows can lead to serious bank erosion and inundation of populated areas near rivers. Seismic waves can be generated by landquake events which can be described as time-dependent forces (unloading/reloading cycles) acting on the Earth. In this study, we conduct inversions of long-period (LP, period ≥20 s) waveforms for the landquake force histories (LFHs) of ten events, which provide quantitative characterization of the initiation, propagation and termination stages of the slope failures. When the results obtained from LP waveforms are analyzed together with high-frequency (HF, 1-3 Hz) seismic signals, we find a relatively strong late-arriving seismic phase (dubbed Dam-forming phase or D-phase) recorded clearly in the HF waveforms at the closest stations, which potentially marks the time when the collapsed masses sliding into river and perhaps even impacting the topographic barrier on the opposite bank. Consequently, our approach to analyzing the LP and HF waveforms developed in this study has a high potential for identifying five dam-forming landquake events (DFLEs) in near real-time using broadband seismic records, which can provide timely warnings of the impending floods to downstream residents.

The size, distribution, and mobility of landslides caused by the 2015 Mw7.8 Gorkha earthquake, Nepal

NASA Astrophysics Data System (ADS)

Roback, Kevin; Clark, Marin K.; West, A. Joshua; Zekkos, Dimitrios; Li, Gen; Gallen, Sean F.; Chamlagain, Deepak; Godt, Jonathan W.

2018-01-01

consistent with compilations of data on larger slope failures. In general, the size ratios of landslide source area to full landslide area are smaller than global averages, and hillslope length seems to largely control runout distance, which we propose reflects a topographic control on landslide mobility in this setting. We find that landslide size dictates runout distance and that more than half of the landslide debris was deposited in direct connection with stream channels. Connectivity, which is defined as the spatial proximity of landslides to fluvial channels, is greatest for larger landslides in the high-relief part of the High Himalaya. Although these failures are less abundant than those at lower elevations, they may have a disproportionate impact on sediment dynamics and cascading hazards, such as landslide reactivation by monsoon rainfall and landslide dams that lead to outburst floods. The overall high fluvial connectivity of coseismic landsliding in the Gorkha event suggests coupling between the earthquake cycle and sediment/geochemical budgets of fluvial systems in the Himalaya.

Geologic Hazards Associated With a Proposed Dam on the Yarlung-Tsangpo River in SE Tibet

NASA Astrophysics Data System (ADS)

Zeitler, P. K.; Meltzer, A. S.; Hallet, B.; Kidd, W. S.; Koons, P. O.

2007-12-01

For a decade anecdotes and media reports have been circulating about a proposed dam on the Yarlung- Tsangpo River in SE Tibet. The proposed site is in the deep canyon of the Yarlung-Tsangpo where the river leaves the Tibetan Plateau across an immense knickpoint, falling ~2000 m along an irregular U-shaped reach ~100 km in length. The fundamental purpose of the dam is generation of ~40,000 MW of hydropower, to be used in diverting a portion of the impounded river to water-starved regions of northern China. Offsetting benefits that would accrue from improved water supply in the north, debate has centered on the water-flow and sediment-flux impacts that would be felt downstream in the Brahmaputra system in northeastern India and Bangladesh, as well as the impact of a dam and large lake on the pristine, ecologically and ethnographically diverse area around the Yarlung-Tsangpo canyon, an area of great significance to Tibetan Buddhists. We have been examining the geodynamic evolution of eastern Tibet, and have gathered considerable geophysical and geological data on the knickpoint region. The knickpoint traverses the Namche Barwa-Gyala Peri massif, one of the most geologically active regions on Earth. In this region, very rapid bedrock exhumation at rates of 7 mm/yr or more has exposed granites as young as 1 Ma, and these rates have been ongoing for at least the past 3 m.y. Detrital-dating evidence shows that these high rates continue at present and that erosion within the massif contributes fully 50% of the suspended-sediment load in the Yarlung-Tsangpo at the point where it enters the Brahmaputra (this would be about 100 Mt/yr derived from the massif). The steep slopes in the massif fail by pervasive landsliding and suggest a steady-state topography where the high erosion rates are balanced by equivalent rates of rock uplift accommodated by numerous active structures. At a more regional scale, GPS results show that steep three-dimensional velocity gradients exist

Reconstructing Sediment Supply, Transport and Deposition Behind the Elwha River Dams

NASA Astrophysics Data System (ADS)

Beveridge, C.

2017-12-01

The Elwha River watershed in Olympic National Park of Washington State, USA is predominantly a steep, mountainous landscape where dominant geomorphic processes include landslides, debris flows and gullying. The river is characterized by substantial variability of channel morphology and fluvial processes, and alternates between narrow bedrock canyons and wider alluvial reaches for much of its length. Literature suggests that the Elwha watershed is topographically and tectonically in steady state. The removal of the two massive hydropower dams along the river in 2013 marked the largest dam removal in history. Over the century long lifespan of the dams, approximately 21 million cubic meters of sediment was impounded behind them. Long term erosion rates documented in this region and reservoir sedimentation data give unprecedented opportunities to test watershed sediment yield models and examine dominant processes that control sediment yield over human time scales. In this study, we aim to reconstruct sediment supply, transport and deposition behind the Glines Canyon Dam (most upstream dam) over its lifespan using a watershed modeling approach. We developed alternative models of varying complexity for sediment production and transport at the network scale driven by hydrologic forcing. We simulate sediment supply and transport in tributaries upstream of the dam. The modeled sediment supply and transport dynamics are based on calibrated formulae (e.g., bedload transport is simulated using Wilcock-Crowe 2003 with modification based on observed bedload transport in the Elwha River). Observational data that aid in our approach include DEM, channel morphology, meteorology, and streamflow and sediment (bedload and suspended load) discharge. We aim to demonstrate how the observed sediment yield behind the dams was influenced by upstream transport supply and capacity limitations, thereby demonstrating the scale effects of flow and sediment transport processes in the Elwha River

ADVICE: A New Approach for Near-Real-Time Monitoring of Surface Displacements in Landslide Hazard Scenarios

PubMed Central

Allasia, Paolo; Manconi, Andrea; Giordan, Daniele; Baldo, Marco; Lollino, Giorgio

2013-01-01

We present a new method for near-real-time monitoring of surface displacements due to landslide phenomena, namely ADVanced dIsplaCement monitoring system for Early warning (ADVICE). The procedure includes: (i) data acquisition and transfer protocols; (ii) data collection, filtering, and validation; (iii) data analysis and restitution through a set of dedicated software; (iv) recognition of displacement/velocity threshold, early warning messages via SMS and/or emails; (v) automatic publication of the results on a dedicated webpage. We show how the system evolved and the results obtained by applying ADVICE over three years into a real early warning scenario relevant to a large earthflow located in southern Italy. ADVICE has speed-up and facilitated the understanding of the landslide phenomenon, the communication of the monitoring results to the partners, and consequently the decision-making process in a critical scenario. Our work might have potential applications not only for landslide monitoring but also in other contexts, as monitoring of other geohazards and of complex infrastructures, as open-pit mines, buildings, dams, etc. PMID:23807688

ADVICE: a new approach for near-real-time monitoring of surface displacements in landslide hazard scenarios.

PubMed

Allasia, Paolo; Manconi, Andrea; Giordan, Daniele; Baldo, Marco; Lollino, Giorgio

2013-06-27

We present a new method for near-real-time monitoring of surface displacements due to landslide phenomena, namely ADVanced dIsplaCement monitoring system for Early warning (ADVICE). The procedure includes: (i) data acquisition and transfer protocols; (ii) data collection, filtering, and validation; (iii) data analysis and restitution through a set of dedicated software; (iv) recognition of displacement/velocity threshold, early warning messages via SMS and/or emails; (v) automatic publication of the results on a dedicated webpage. We show how the system evolved and the results obtained by applying ADVICE over three years into a real early warning scenario relevant to a large earthflow located in southern Italy. ADVICE has speed-up and facilitated the understanding of the landslide phenomenon, the communication of the monitoring results to the partners, and consequently the decision-making process in a critical scenario. Our work might have potential applications not only for landslide monitoring but also in other contexts, as monitoring of other geohazards and of complex infrastructures, as open-pit mines, buildings, dams, etc.

Landslides and Mudslides

MedlinePlus

... from landslides and debris flows In the United States, landslides and debris flows result in 25 to 50 deaths each year. ... and debris flows. Learn whether landslides or debris flows have ... department, state geological surveys or departments of natural resources, or ...

Characterization of Landslide Sites in Puerto Rico after Hurricanes Irma and María

NASA Astrophysics Data System (ADS)

Hughes, K. S.; Morales Vélez, A. C.

2017-12-01

Thousands of landslides in Puerto Rico and the U.S. Virgin Islands were triggered by the passage of Hurricanes Irma (Sep. 6) and María (Sep. 20) in 2017. Both were classified as Category 5 hurricanes on the Saffir-Simpson scale before making landfall. Most of the mass wasting occurred in the rugged mountainous regions of Puerto Rico and—along with bridge collapse, flooding, and the threat of dam failure—left many communities isolated for up to a month or longer. Aerial photography collected by FEMA and the Civil Air Patrol have allowed for the rapid inventory of landslide sites across the archipelago by the USGS and other groups. Using this dataset and other local information, we identified a list of priority sites that were documented in detail as part of a NSF-GEER (Geotechnical Extreme Event Reconnaissance) mission. The juvenile landscape and short-wavelength topography in most of Puerto Rico present considerable landslide risk that is exaggerated during heavy rainfall events like Hurricane María. Our preliminary work shows that natural escarpments, de-vegetated pastureland in mountainous areas, and road cuts along incised river valleys were areas of concentrated failures during these storms. Notably, the northern karst area suffered fewer failures than the arc basement rocks exposed elsewhere in the island. In addition to previously active landslides at specific sites on the island, new landslides along PR-143 in the municipality of Barranquitas, PR-431 in the municipality of Lares, and PR-109 in the municipality of Añasco are among important mass wasting events that were a focus of the GEER team and remain important in our ongoing research. A team of undergraduate and graduate students led by faculty at the University of Puerto Rico in Mayagüez are working to characterize the complete inventory of landslides in terms of underlying geology, soil type, slope, curvature, rain fall amounts during both atmospheric events, and other local geomorphic and

The size, distribution, and mobility of landslides caused by the 2015 Mw7.8 Gorkha earthquake, Nepal

USGS Publications Warehouse

Roback, Kevin; Clark, Marin K.; West, A. Joshua; Zekkos, Dimitrios; Li, Gen; Gallen, Sean F.; Chamlagain, Deepak; Godt, Jonathan W.

2018-01-01

is consistent with compilations of data on larger slope failures. In general, the size ratios of landslide source area to full landslide area are smaller than global averages, and hillslope length seems to largely control runout distance, which we propose reflects a topographic control on landslide mobility in this setting. We find that landslide size dictates runout distance and that more than half of the landslide debris was deposited in direct connection with stream channels. Connectivity, which is defined as the spatial proximity of landslides to fluvial channels, is greatest for larger landslides in the high-relief part of the High Himalaya. Although these failures are less abundant than those at lower elevations, they may have a disproportionate impact on sediment dynamics and cascading hazards, such as landslide reactivation by monsoon rainfall and landslide dams that lead to outburst floods. The overall high fluvial connectivity of coseismic landsliding in the Gorkha event suggests coupling between the earthquake cycle and sediment/geochemical budgets of fluvial systems in the Himalaya.

Rapid reservoir erosion, hyperconcentrated flow, and downstream deposition triggered by breaching of 38 m tall Condit Dam, White Salmon River, Washington

USGS Publications Warehouse

Wilcox, Andrew C.; O'Connor, James E.; Major, Jon J.

2014-01-01

Condit Dam on the White Salmon River, Washington, a 38 m high dam impounding a large volume (1.8 million m3) of fine-grained sediment (60% sand, 35% silt and clay, and 5% gravel), was rapidly breached in October 2011. This unique dam decommissioning produced dramatic upstream and downstream geomorphic responses in the hours and weeks following breaching. Blasting a 5 m wide hole into the base of the dam resulted in rapid reservoir drawdown, abruptly releasing ~1.6 million m3 of reservoir water, exposing reservoir sediment to erosion, and triggering mass failures of the thickly accumulated reservoir sediment. Within 90 min of breaching, the reservoir's water and ~10% of its sediment had evacuated. At a gauging station 2.3 km downstream, flow increased briefly by 400 m3 s−1during passage of the initial pulse of released reservoir water, followed by a highly concentrated flow phase—up to 32% sediment by volume—as landslide-generated slurries from the reservoir moved downstream. This hyperconcentrated flow, analogous to those following volcanic eruptions or large landslides, draped the downstream river with predominantly fine sand. During the ensuing weeks, suspended-sediment concentration declined and sand and gravel bed load derived from continued reservoir erosion aggraded the channel by >1 m at the gauging station, after which the river incised back to near its initial elevation at this site. Within 15 weeks after breaching, over 1 million m3 of suspended load is estimated to have passed the gauging station, consistent with estimates that >60% of the reservoir's sediment had eroded. This dam removal highlights the influence of interactions among reservoir erosion processes, sediment composition, and style of decommissioning on rate of reservoir erosion and consequent downstream behavior of released sediment.

Extreme rainfall-induced landslide changes based on landslide susceptibility in China, 1998-2015

NASA Astrophysics Data System (ADS)

Li, Weiyue; Liu, Chun; Hong, Yang

2017-04-01

Nowadays, landslide has been one of the most frequent and seriously widespread natural hazards all over the world. Rainfall, especially heavy rainfall is a trigger to cause the landslide occurrence, by increasing soil pore water pressures. In China, rainfall-induced landslides have risen up over to 90% of the total number. Rainfall events sometimes generate a trend of extremelization named rainfall extremes that induce the slope failure suddenly and severely. This study shows a method to simulate the rainfall-induced landslide spatio-temporal distribution on the basis of the landslide susceptibility index. First, the study on landslide susceptibility in China is introduced. We set the values of the index to the range between 0 and 1. Second, we collected TRMM 3B42 precipitation products spanning the years 1998-2015 and extracted the daily rainfall events greater than 50mm/day as extreme rainfall. Most of the rainfall duration time that may trigger a landslide has resulted between 3 hours and 45 hours. The combination of these two aspects can be exploited to simulate extreme rainfall-induced landslide distribution and illustrate the changes in 17 years. This study shows a useful tool to be part of rainfall-induced landslide simulation methodology for landslide early warning.

Owyhee River intracanyon lava flows: does the river give a dam?

USGS Publications Warehouse

Ely, Lisa L.; Brossy, Cooper C.; House, P. Kyle; Safran, Elizabeth B.; O'Connor, Jim E.; Champion, Duane E.; Fenton, Cassandra R.; Bondre, Ninad R.; Orem, Caitlin A.; Grant, Gordon E.; Henry, Christopher D.; Turrin, Brent D.

2013-01-01

to fill the blocked valley. Variations in this primary process of incision through the lava dams could be influenced by additional independent factors such as regional uplift, drainage integration, or climate that affect the relative base level, discharge, and sediment yield within the watershed. By redirecting the river, tributaries, and subsequent lava flows to different parts of the canyon, lava dams create a distinct valley morphology of flat, broad basalt shelves capping steep cliffs of Tertiary sediment. This stratigraphy is conducive to landsliding and extends the effects of intracanyon lava flows on channel geomorphology beyond the lifetime of the dams.

Implementation of a landslide early warning system based on near-real-time monitoring, multisensor mapping and geophysical measurements

NASA Astrophysics Data System (ADS)

Teza, Giordano; Galgaro, Antonio; Francese, Roberto; Ninfo, Andrea; Mariani, Rocco

2017-04-01

An early warning system has been implemented to monitor the Perarolo di Cadore landslide (North-Eastern Italian Alps), which is a slump whose induced risk is fairly high because a slope collapse could form a temporary dam on the underlying torrent and, therefore, could directly threaten the close village. A robotic total station (RTS) measures, with 6h returning time, the positions of 23 retro-reflectors placed on the landslide upper and middle sectors. The landslide's kinematical behavior derived from these near-real-time (NRT) surface displacements is interpreted on the basis of available geomorphological and geological information, geometrical data provided by some laser scanning and photogrammetric surveys, and a landslide model obtained by means of 3D Electrical Resistivity Tomography (3D ERT) measurements. In this way, an analysis of the time series provided by RTS and a pluviometer, which cover several years, allows the definition of some pre-alert and alert kinematical and rainfall thresholds. These thresholds, as well as the corresponding operational recommendations, are currently used for early warning purposes by Authorities involved in risk management for the Perarolo landslide. It should be noted the fact that, as new RTS and pluviometric data are available, the thresholds can be updated and, therefore, a fine tuning of the early warning system can be carried out in order to improve its performance. Although the proposed approach has been implemented in a particular case, it can be used to develop an early warning system based on NRT data in each site where a landslide threatens infrastructures and/or villages that cannot be relocated.

The Corfu Landslide: Analog to Giant Landslides on Mars

NASA Technical Reports Server (NTRS)

Lewis, S. W.; Baker, V. R.

1984-01-01

In an analog to the great landslides of the Vales Marineris, Mars, a detailed study was made of the Corfu Landslide in south-central Washington. This prehistoric slide is located on the northern flank of the Saddle Mountains, southwest of Othello, Washington. The slide covers a 13 square km area centered on section 11 of T.15N., R.27E., Willamette Meridian, adjacent to the Corfu townsite. Approximately 1 cubic km of material is involved in sliding that was probably initiated by Missoula flooding through the Channeled Scabland. It is concluded that there were four primary factors involved in the initiation of the Corfu landsliding: (1) A slip surface was present at the right orientation; (2) Glacial flooding undercut the slope; (3) Wetter climatic conditions prevailed during that time period; and (4) Some seismic vibrations, known to occur locally, probably acted as a trigger. These factors show that special conditions were required in conjunction to produce landsliding. Studies in progress of the Vales Marieneris suggest that the same factors probably contributed to landsliding there.

The National Landslide Information Center; data to reduce landslide damage

USGS Publications Warehouse

Brown, W. M.

1992-01-01

In a world of persistent and increasing construction on and occupation of hillslopes, canyons, and coastal bluffs, landslides are exacting an inexorable toll of human life and economic loss. In the 1980's, massive landslides disasters occurred throughout the world, many in regions where such disasters were historically unprecedented, or where their potential was forgotten or disregarded. by present generations. In some cases, large populations had moved onto unstable lands before renewed landslide activity. For example, the San Francisco Bay region in population between 1955 and 1982, and much of the new development occurred on hillsides and in canyons. Major rainstorms in both 1955 and 1982 produced abundant landslides throughout the region, but the landslides in 1982 proved much more devastating than those in 1955 because of the increased population density on sloping ground. Similar situations persist in many other population centers surrounded by hills and mountains, such as Rio de Janeiro, Hong Kong, and Los Angeles. 

Topographic Controls on Landslide and Debris-Flow Mobility

NASA Astrophysics Data System (ADS)

McCoy, S. W.; Pettitt, S.

2014-12-01

Regardless of whether a granular flow initiates from failure and liquefaction of a shallow landslide or from overland flow that entrains sediment to form a debris flow, the resulting flow poses hazards to downslope communities. Understanding controls on granular-flow mobility is critical for accurate hazard prediction. The topographic form of granular-flow paths can vary significantly across different steeplands and is one of the few flow-path properties that can be readily altered by engineered control structures such as closed-type check dams. We use grain-scale numerical modeling (discrete element method simulations) of free-surface, gravity-driven granular flows to investigate how different topographic profiles with the same mean slope and total relief can produce notable differences in flow mobility due to strong nonlinearities inherent to granular-flow dynamics. We describe how varying the profile shape from planar, to convex up, to concave up, as well how varying the number, size, and location of check dams along a flow path, changes flow velocity, thickness, discharge, energy dissipation, impact force and runout distance. Our preliminary results highlight an important path dependence for this nonlinear system, show that caution should be used when predicting flow dynamics from path-averaged properties, and provide some mechanics-based guidance for engineering control structures.

Ganges Chasma Landslide

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 01 April 2002) This image shows a spectacular landslide along a portion of the southern wall of Ganges Chasma within Valles Marineris. Landslides have very characteristic morphologies on Earth, which they also display on Mars. These morphologies include a distinctive escarpment at the uppermost part of the landslide--called a head scarp (seen at the bottom of this image), a down-dropped block of material below that escarpment that dropped almost vertically, and a deposit of debris that moved away from the escarpment at high speed. In this example, the wall rock displayed in the upper part of the cliff is layered, with spurs and chutes created by differing amounts of erosion. Below the steep scarp is a smoother, steep slope of material with small, narrow tongues of debris that have eroded off of the escarpment since the landslide occurred (a talus slope). The actual landslide deposit, visible in the upper half of this image, shows striations that form by differences in the side-by-side motion during high velocity emplacement. This immense landslide traveled some 70 km at speeds that probably exceeded 100 kilometers per hour (60 miles per hour) before coming to rest, forming abrupt, terminal fronts (upper right corner of image). Even at these high speeds, this massive landslide was moving for nearly an hour before it came to rest.

Regional coseismic landslide hazard assessment without historical landslide inventories: A new approach

NASA Astrophysics Data System (ADS)

Kritikos, Theodosios; Robinson, Tom R.; Davies, Tim R. H.

2015-04-01

Currently, regional coseismic landslide hazard analyses require comprehensive historical landslide inventories as well as detailed geotechnical data. Consequently, such analyses have not been possible where these data are not available. A new approach is proposed herein to assess coseismic landslide hazard at regional scale for specific earthquake scenarios in areas without historical landslide inventories. The proposed model employs fuzzy logic and geographic information systems to establish relationships between causative factors and coseismic slope failures in regions with well-documented and substantially complete coseismic landslide inventories. These relationships are then utilized to estimate the relative probability of landslide occurrence in regions with neither historical landslide inventories nor detailed geotechnical data. Statistical analyses of inventories from the 1994 Northridge and 2008 Wenchuan earthquakes reveal that shaking intensity, topography, and distance from active faults and streams are the main controls on the spatial distribution of coseismic landslides. Average fuzzy memberships for each factor are developed and aggregated to model the relative coseismic landslide hazard for both earthquakes. The predictive capabilities of the models are assessed and show good-to-excellent model performance for both events. These memberships are then applied to the 1999 Chi-Chi earthquake, using only a digital elevation model, active fault map, and isoseismal data, replicating prediction of a future event in a region lacking historic inventories and/or geotechnical data. This similarly results in excellent model performance, demonstrating the model's predictive potential and confirming it can be meaningfully applied in regions where previous methods could not. For such regions, this method may enable a greater ability to analyze coseismic landslide hazard from specific earthquake scenarios, allowing for mitigation measures and emergency response plans

Application and evaluation of a rapid response earthquake-triggered landslide model to the 25 April 2015 Mw 7.8 Gorkha earthquake, Nepal

USGS Publications Warehouse

Gallen, Sean F.; Clark, Marin K.; Godt, Jonathan W.; Roback, Kevin; Niemi, Nathan A

2017-01-01

The 25 April 2015 Mw 7.8 Gorkha earthquake produced strong ground motions across an approximately 250 km by 100 km swath in central Nepal. To assist disaster response activities, we modified an existing earthquake-triggered landslide model based on a Newmark sliding block analysis to estimate the extent and intensity of landsliding and landslide dam hazard. Landslide hazard maps were produced using Shuttle Radar Topography Mission (SRTM) digital topography, peak ground acceleration (PGA) information from the U.S. Geological Survey (USGS) ShakeMap program, and assumptions about the regional rock strength based on end-member values from previous studies. The instrumental record of seismicity in Nepal is poor, so PGA estimates were based on empirical Ground Motion Prediction Equations (GMPEs) constrained by teleseismic data and felt reports. We demonstrate a non-linear dependence of modeled landsliding on aggregate rock strength, where the number of landslides decreases exponentially with increasing rock strength. Model estimates are less sensitive to PGA at steep slopes (> 60°) compared to moderate slopes (30–60°). We compare forward model results to an inventory of landslides triggered by the Gorkha earthquake. We show that moderate rock strength inputs over estimate landsliding in regions beyond the main slip patch, which may in part be related to poorly constrained PGA estimates for this event at far distances from the source area. Directly above the main slip patch, however, the moderate strength model accurately estimates the total number of landslides within the resolution of the model (landslides ≥ 0.0162 km2; observed n = 2214, modeled n = 2987), but the pattern of landsliding differs from observations. This discrepancy is likely due to the unaccounted for effects of variable material strength and local topographic amplification of strong ground motion, as well as other simplifying assumptions about source characteristics and their

On the characteristics of landslide tsunamis

PubMed Central

Løvholt, F.; Pedersen, G.; Harbitz, C. B.; Glimsdal, S.; Kim, J.

2015-01-01

This review presents modelling techniques and processes that govern landslide tsunami generation, with emphasis on tsunamis induced by fully submerged landslides. The analysis focuses on a set of representative examples in simplified geometries demonstrating the main kinematic landslide parameters influencing initial tsunami amplitudes and wavelengths. Scaling relations from laboratory experiments for subaerial landslide tsunamis are also briefly reviewed. It is found that the landslide acceleration determines the initial tsunami elevation for translational landslides, while the landslide velocity is more important for impulsive events such as rapid slumps and subaerial landslides. Retrogressive effects stretch the tsunami, and in certain cases produce enlarged amplitudes due to positive interference. In an example involving a deformable landslide, it is found that the landslide deformation has only a weak influence on tsunamigenesis. However, more research is needed to determine how landslide flow processes that involve strong deformation and long run-out determine tsunami generation. PMID:26392615

Developing Digital Image Techniques with Low-Cost Unmanned Mobile to Monitor the Safety of Dam and Affiliated Structure

NASA Astrophysics Data System (ADS)

Sung, Wen-Pei; Shih, Ming-Hsiang

2016-04-01

Global warming phenomena are increasingly serious, the El Niño and La Niña continue to occur repeatedly, causing the irregular drought and flood problem repeatedly. Mountain form of Taiwan is steep and storage ability of rainwater is insufficient to supply the livelihood of people and usage of industry which need to rely on rainwater reservoir. Thus, to ensure the water supply and self-reliance energy supply, one of ways to keep water resource is to build reservoir. Nevertheless, Taiwan is located on Pacific seismic belt; additionally, geological conditions are not fine, over-developed in the hills lead to more natural disasters in the future. Thus, strong shakes and typhoons which caused a degree of severe landslides around dam lead to reduce catchment of dam to result in affecting the safety of dam. Otherwise, the cracks and rusts in dam, induced by the defects of material, bad construction and seismic excitation respectively, thus, the mechanics phenomena of dam and its affiliated structures with crack are probing into the cause of stress concentration, induced high crack increase rate, affect the safety and usage of dam. This research is aimed at the safety evaluation technique of dam and its affiliated structures to develop three dimensional digital image correlation techniques for monitoring the safety of dam and its affiliated structures. Namely, developing the unmanned mobile on two axis of digital image correlation method is to detect the digital images from geometric scanning techniques for dam structure. This developed technique combined with Unmanned Aerial Vehicle (UAV) to develop the near filed scanning and monitoring techniques for local deformation and cracks on dam and its affiliated structures.

Identification of landslide-prone zones in the geomorphically and climatically sensitive Mandakini valley, (central Himalaya), for disaster governance using the Weights of Evidence method

NASA Astrophysics Data System (ADS)

Poonam; Rana, Naresh; Champati ray, Parshant Kumar; Bisht, Pinkey; Bagri, Dhirendra Singh; Wasson, Robert James; Sundriyal, Yashpal

2017-05-01

The entire Himalayan region is prone to disasters, with many people being vulnerable to hydroclimatic threats such as extreme rainfall-driven floods, glacial lake outburst floods (GLOFs), landslide lake outburst floods (LLOFs), and landslides triggered by rainfall. Landslides and floods are related, as the former cause the lakes that burst, and floods can undercut slopes and cause landslides. During the past 200 years, landslides and floods caused by LLOFs in the Garhwal Himalaya have occurred in 1894, 1970, and 1978; but the most disastrous event, in terms of loss of life and economic impact, occurred in June 2013, which was a result of extreme rainfall in the Higher Himalaya and breaching of a moraine-dammed lake, very short-lived LLOFs, and rainfall-induced runoff and landslides. Outmigration from the area as a result of the 2013 event has caused anxiety about the future of the economy and also concerns about security of a state that has an international border. As a contribution to planning and reconstruction to secure the livelihoods of the local people and to entice migrants to return, this paper identifies zones in the Mandakini valley susceptible to landslides using a 'Weights of Evidence' approach. The roles of climate, geology, and geomorphology of the valley are also given attention to explain the reasons for the disastrous event of June 2013. The results of the research presented here may be an important input to disaster governance.

Landslides triggered by the 14 November 2016 Mw 7.8 Kaikōura Earthquake, New Zealand

USGS Publications Warehouse

Massey, C.; Townsend, D.; Rathje, Ellen M.; Allstadt, Kate E.; Lukovic, B.; Kaneko, Yoshihiro; Bradley, Brendon A.; Wartman, J.; Jibson, Randall W.; Petley, D. N.; Horspool, Nick; Hamling, I.; Carey, J.; Cox, S.; Davidson, John; Dellow, S.; Godt, Jonathan W.; Holden, Christopher; Jones, Katherine D.; Kaiser, Anna E.; Little, M.; Lyndsell, B.; McColl, S.; Morgenstern, R.; Rengers, Francis K.; Rhoades, D.; Rosser, B.; Strong, D.; Singeisen, C.; Villeneuve, M.

2018-01-01

The 14 November 2016 Mw">MwMw 7.8 Kaikōura earthquake generated more than 10,000 landslides over a total area of about 10,000  km2">10,000  km210,000  km2, with the majority concentrated in a smaller area of about 3600  km2">3600  km23600  km2. The largest landslide triggered by the earthquake had an approximate volume of 20(±2)  M m3">20(±2)  M m320(±2)  M m3, with a runout distance of about 2.7 km, forming a dam on the Hapuku River. In this article, we present version 1.0 of the landslide inventory we have created for this event. We use the inventory presented in this article to identify and discuss some of the controls on the spatial distribution of landslides triggered by the Kaikōura earthquake. Our main findings are (1) the number of medium to large landslides (source area ≥10,000  m2">≥10,000  m2≥10,000  m2) triggered by the Kaikōura earthquake is smaller than for similar‐sized landslides triggered by similar magnitude earthquakes in New Zealand; (2) seven of the largest eight landslides (from 5 to 20  M m3">20  M m320  M m3) occurred on faults that ruptured to the surface during the earthquake; (3) the average landslide density within 200 m of a mapped surface fault rupture is three times that at a distance of 2500 m or more from a mapped surface fault rupture; (4) the “distance to fault” predictor variable, when used as a proxy for ground‐motion intensity, and when combined with slope angle, geology, and elevation variables, has more power in predicting landslide probability than the modeled peak ground acceleration or peak ground velocity; and (5) for the same slope angles, the coastal slopes have landslide point densities that are an order of magnitude greater than those in similar materials on the inland slopes, but their source areas are significantly smaller.

New Zealand's National Landslide Database

NASA Astrophysics Data System (ADS)

Rosser, B.; Dellow, S.; Haubrook, S.; Glassey, P.

2016-12-01

Since 1780, landslides have caused an average of about 3 deaths a year in New Zealand and have cost the economy an average of at least NZ$250M/a (0.1% GDP). To understand the risk posed by landslide hazards to society, a thorough knowledge of where, when and why different types of landslides occur is vital. The main objective for establishing the database was to provide a centralised national-scale, publically available database to collate landslide information that could be used for landslide hazard and risk assessment. Design of a national landslide database for New Zealand required consideration of both existing landslide data stored in a variety of digital formats, and future data, yet to be collected. Pre-existing databases were developed and populated with data reflecting the needs of the landslide or hazard project, and the database structures of the time. Bringing these data into a single unified database required a new structure capable of storing and delivering data at a variety of scales and accuracy and with different attributes. A "unified data model" was developed to enable the database to hold old and new landslide data irrespective of scale and method of capture. The database contains information on landslide locations and where available: 1) the timing of landslides and the events that may have triggered them; 2) the type of landslide movement; 3) the volume and area; 4) the source and debris tail; and 5) the impacts caused by the landslide. Information from a variety of sources including aerial photographs (and other remotely sensed data), field reconnaissance and media accounts has been collated and is presented for each landslide along with metadata describing the data sources and quality. There are currently nearly 19,000 landslide records in the database that include point locations, polygons of landslide source and deposit areas, and linear features. Several large datasets are awaiting upload which will bring the total number of landslides to

On the characteristics of landslide tsunamis.

PubMed

Løvholt, F; Pedersen, G; Harbitz, C B; Glimsdal, S; Kim, J

2015-10-28

This review presents modelling techniques and processes that govern landslide tsunami generation, with emphasis on tsunamis induced by fully submerged landslides. The analysis focuses on a set of representative examples in simplified geometries demonstrating the main kinematic landslide parameters influencing initial tsunami amplitudes and wavelengths. Scaling relations from laboratory experiments for subaerial landslide tsunamis are also briefly reviewed. It is found that the landslide acceleration determines the initial tsunami elevation for translational landslides, while the landslide velocity is more important for impulsive events such as rapid slumps and subaerial landslides. Retrogressive effects stretch the tsunami, and in certain cases produce enlarged amplitudes due to positive interference. In an example involving a deformable landslide, it is found that the landslide deformation has only a weak influence on tsunamigenesis. However, more research is needed to determine how landslide flow processes that involve strong deformation and long run-out determine tsunami generation. © 2015 The Authors.

Landslides in Valles Marineris, Mars.

USGS Publications Warehouse

Lucchitta, B.K.

1979-01-01

Large landslides in the Martian equatorial troughs have been investigated with respect to morphology, geologic structure of the troughs, time of emplacement, similarity to terrestrial landslides, and origin and mechanism of transport. The morphologic variations of the landslides can be attributed mainly to their degree of confinement on trough floors. The huge size of many landslides is due to their occurrence on fault scarps that may have attained several kilometers in height in the absence of vigorous fluvial erosion on Mars. The mechanical efficiency of the Martian landslides is high but in accord with predictions from large landslides on earth. -from Author

Constraining relationships between rainfall and landsliding with satellite derived rainfall measurements and landslide inventories.

NASA Astrophysics Data System (ADS)

Marc, Odin; Malet, Jean-Philippe; Stumpf, Andre; Gosset, Marielle

2017-04-01

In mountainous and hilly regions, landslides are an important source of damage and fatalities. Landsliding correlates with extreme rainfall events and may increase with climate change. Still, how precipitation drives landsliding at regional scales is poorly understood quantitatively in part because constraining simultaneously landsliding and rainfall across large areas is challenging. By combining optical images acquired from satellite observation platforms and rainfall measurements from satellite constellations we are building a database of landslide events caused by with single storm events. We present results from storm-induced landslides from Brazil, Taiwan, Micronesia, Central America, Europe and the USA. We present scaling laws between rainfall metrics derived by satellites (total rainfall, mean intensity, antecedent rainfall, ...) and statistical descriptors of landslide events (total area and volume, size distribution, mean runout, ...). Total rainfall seems to be the most important parameter driving non-linearly the increase in total landslide number, and area and volume. The maximum size of bedrock landslides correlates with the total number of landslides, and thus with total rainfall, within the limits of available topographic relief. In contrast, the power-law scaling exponent of the size distribution, controlling the relative abundance of small and large landslides, appears rather independent of the rainfall metrics (intensity, duration and total rainfall). These scaling laws seem to explain both the intra-storm pattern of landsliding, at the scale of satellite rainfall measurements ( 25kmx25km), and the different impacts observed for various storms. Where possible, we evaluate the limits of standard rainfall products (TRMM, GPM, GSMaP) by comparing them to in-situ data. Then we discuss how slope distribution and other geomorphic factors (lithology, soil presence,...) modulate these scaling laws. Such scaling laws at the basin scale and based only on a

Spatial prediction of landslide susceptibility in parts of Garhwal Himalaya, India, using the weight of evidence modelling.

PubMed

Guri, Pardeep Kumar; Ray, P K Champati; Patel, Ramesh Chandra

2015-06-01

Garhwal Himalaya in northern India has emerged as one of the most prominent hot spots of landslide occurrences in the Himalaya mainly due to geological causes related to mountain building processes, steep topography and frequent occurrences of extreme precipitation events. As this region has many pilgrimage and tourist centres, it is visited by hundreds of thousands of people every year, and in the recent past, there has been rapid development to provide adequate roads and building infrastructure. Additionally, attempts are also made to harness hydropower by constructing tunnels, dams and reservoirs and thus altering vulnerable slopes at many places. As a result, the overall risk due to landslide hazards has increased many folds and, therefore, an attempt was made to assess landslide susceptibility using 'Weights of Evidence (WofE)', a well-known bivariate statistical modelling technique implemented in a much improved way using remote sensing and Geographic Information System. This methodology has dual advantage as it demonstrates how to derive critical parameters related to geology, geomorphology, slope, land use and most importantly temporal landslide distribution in one of the data scarce region of the world. Secondly, it allows to experiment with various combination of parameters to assess their cumulative effect on landslides. In total, 15 parameters related to geology, geomorphology, terrain, hydrology and anthropogenic factors and 2 different landslide inventories (prior to 2007 and 2008-2011) were prepared from high-resolution Indian remote sensing satellite data (Cartosat-1 and Resourcesat-1) and were validated by field investigation. Several combinations of parameters were carried out using WofE modelling, and finally using best combination of eight parameters, 76.5 % of overall landslides were predicted in 24 % of the total area susceptible to landslide occurrences. The study has highlighted that using such methodology landslide susceptibility assessment

Landslide in Sirenum

NASA Technical Reports Server (NTRS)

2004-01-01

27 August 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a landslide deposit in a deep trough in Terra Sirenum near 26.1oS, 140.0oW. After the landslide occurred, subsequent erosion of the slope produced talus that covers part of the landslide deposit. This area is about 3 km (1.9 mi) across; sunlight illuminates the scene from the lower left.

106. DAM EARTH DIKE SUBMERSIBLE DAMS & DIKE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

106. DAM - EARTH DIKE - SUBMERSIBLE DAMS & DIKE CONN. AT MOVABLE DAM (ML-8-52/2-FS) March 1940 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

DAM Safety and Deformation Monitoring in Dams

NASA Astrophysics Data System (ADS)

Kalkan, Y.; Bilgi, S.; Potts, L.; Miiama, J.; Mahgoub, M.; Rahman, S.

2013-12-01

Water is the life and necessity to water is increasing day by day with respect to the World population, rising of living standards and destruction of nature. Thus, the importance of water and water structures have been increasing gradually. Dams are among the most important engineering structures used for water supplies, flood controls, agricultural purposes as well as drinking and hydroelectric power. There are about 150.000 large size dams in the World. Especially after the Second World War, higher and larger capacity dams have been constructed. Dams create certain risks like the other manmade structures. No one knows precisely how many dam failures have occurred in the World, whereas hundreds of dam failures have occurred throughout the U.S. history. Some basic physical data are very important for assessing the safety and performance of dams. These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. These physical data are measured and monitored by the instruments and equipment. Dams and their surroundings have to be monitored by using essential methods at periodic time intervals in order to determine the possible changes that may occur over the time. Monitoring programs typically consist of; surveillance or visual observation. These programs on dams provide information for evaluating the dam's performance related to the design intent and expected changes that could affect the safety performance of the dam. Additionally, these programs are used for investigating and evaluating the abnormal or degrading performance where any remedial action is necessary. Geodetic and non-geodetic methods are used for monitoring. Monitoring the performance of the dams is critical for producing and maintaining the safe dams. This study provides some information, safety and the techniques about the deformation monitoring of the

A landslide susceptibility map of Africa

NASA Astrophysics Data System (ADS)

Broeckx, Jente; Vanmaercke, Matthias; Duchateau, Rica; Poesen, Jean

2017-04-01

Studies on landslide risks and fatalities indicate that landslides are a global threat to humans, infrastructure and the environment, certainly in Africa. Nonetheless our understanding of the spatial patterns of landslides and rockfalls on this continent is very limited. Also in global landslide susceptibility maps, Africa is mostly underrepresented in the inventories used to construct these maps. As a result, predicted landslide susceptibilities remain subject to very large uncertainties. This research aims to produce a first continent-wide landslide susceptibility map for Africa, calibrated with a well-distributed landslide dataset. As a first step, we compiled all available landslide inventories for Africa. This data was supplemented by additional landslide mapping with Google Earth in underrepresented regions. This way, we compiled 60 landslide inventories from the literature (ca. 11000 landslides) and an additional 6500 landslides through mapping in Google Earth (including 1500 rockfalls). Various environmental variables such as slope, lithology, soil characteristics, land use, precipitation and seismic activity, were investigated for their significance in explaining the observed spatial patterns of landslides. To account for potential mapping biases in our dataset, we used Monte Carlo simulations that selected different subsets of mapped landslides, tested the significance of the considered environmental variables and evaluated the performance of the fitted multiple logistic regression model against another subset of mapped landslides. Based on these analyses, we constructed two landslide susceptibility maps for Africa: one for all landslide types and one excluding rockfalls. In both maps, topography, lithology and seismic activity were the most significant variables. The latter factor may be surprising, given the overall limited degree of seismicity in Africa. However, its significance indicates that frequent seismic events may serve as in important

Analysis of Landslide Hazard Impact Using the Landslide Database for Germany

NASA Astrophysics Data System (ADS)

Klose, M.; Damm, B.

2014-12-01

The Federal Republic of Germany has long been among the few European countries that lack a national landslide database. Systematic collection and inventory of landslide data still shows a comprehensive research history in Germany, but only one focused on development of databases with local or regional coverage. This has changed in recent years with the launch of a database initiative aimed at closing the data gap existing at national level. The present contribution reports on this project that is based on a landslide database which evolved over the last 15 years to a database covering large parts of Germany. A strategy of systematic retrieval, extraction, and fusion of landslide data is at the heart of the methodology, providing the basis for a database with a broad potential of application. The database offers a data pool of more than 4,200 landslide data sets with over 13,000 single data files and dates back to 12th century. All types of landslides are covered by the database, which stores not only core attributes, but also various complementary data, including data on landslide causes, impacts, and mitigation. The current database migration to PostgreSQL/PostGIS is focused on unlocking the full scientific potential of the database, while enabling data sharing and knowledge transfer via a web GIS platform. In this contribution, the goals and the research strategy of the database project are highlighted at first, with a summary of best practices in database development providing perspective. Next, the focus is on key aspects of the methodology, which is followed by the results of different case studies in the German Central Uplands. The case study results exemplify database application in analysis of vulnerability to landslides, impact statistics, and hazard or cost modeling.

The Landslide Handbook - A Guide to Understanding Landslides

USGS Publications Warehouse

Highland, Lynn M.; Bobrowsky, Peter

2008-01-01

This handbook is intended to be a resource for people affected by landslides to acquire further knowledge, especially about the conditions that are unique to their neighborhoods and communities. Considerable literature and research are available concerning landslides, but unfortunately little of it is synthesized and integrated to address the geographically unique geologic and climatic conditions around the globe. Landslides occur throughout the world, under all climatic conditions and terrains, cost billions in monetary losses, and are responsible for thousands of deaths and injuries each year. Often, they cause long-term economic disruption, population displacement, and negative effects on the natural environment. Outdated land-use policies may not always reflect the best planning for use of land that is vulnerable to landslides. The reasons for poor or nonexistent land-use policies that minimize the perceived or actual danger and damage potential from geologic hazards are many and encompass the political, cultural, and financial complexities and intricacies of communities. Landslides often are characterized as local problems, but their effects and costs frequently cross local jurisdictions and may become State or Provincial or national problems. Growing populations may be limited in their geographic expansion, except to occupy unstable, steep, or remote areas. Often, stabilizing landslide-scarred areas is too costly, and some inhabitants have no other places to relocate. Fortunately, simple, 'low-tech' precautions and actions can be adopted to at least ensure an individual's immediate safety, and this handbook gives a brief overview of many of these options. We strongly suggest that, where possible, the assistance of professional engineers/geologists or those experienced in the successful mitigation of unstable slopes be consulted before actions are taken. This handbook helps homeowners, community and emergency managers, and decisionmakers to take the positive

Seismic response of soft deposits due to landslide: The Mission Peak, California, landslide

USGS Publications Warehouse

Hartzell, Stephen; Leeds, Alena L.; Jibson, Randall W.

2017-01-01

The seismic response of active and intermittently active landslides is an important issue to resolve to determine if such landslides present an elevated hazard in future earthquakes. To study the response of landslide deposits, seismographs were placed on the Mission Peak landslide in the eastern San Francisco Bay region for a period of one year. Numerous local and near‐regional earthquakes were recorded that reveal a complexity of seismic response phenomena using the horizontal‐to‐vertical spectral ratio method. At lower frequencies, a clear spectral peak is observed at 0.5 Hz common to all four stations in the array and is attributed to a surface topographic effect. At higher frequencies, other spectral peaks occur that are interpreted in terms of local deposits and structures. Site amplification from the standard reference site method shows the minimum amplification with a factor of 2, comparing a site on and off the landslide. A site located on relatively homogeneous deposits of loose soils shows a clear spectral peak associated with the thickness of the deposit. Another site on a talus‐filled graben near the headscarp shows possible 2D or 3D effects from subsurface topography or scattering within and between buried sandstone blocks. A third site on a massive partially detached block below the crown of the headscarp shows indications of resonance caused by the reverberation of shear waves within the block. The varied seismic response of different parts of this complex landslide is consistent with other studies which found that, although landslide response is commonly enhanced in the downslope direction of landslide movement, such a response does not occur uniformly or consistently. When it does occur, enhanced site response parallel to the direction of landslide movement would contribute to landslide reactivation during significant earthquakes.

Landslide in Kasei Valles

NASA Technical Reports Server (NTRS)

2003-01-01

The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) continues in 2003 to return excellent, high resolution images of the red planet's surface. This nearly 1.5 meters (5 ft.) per pixel view of a landslide on a 200 meter-high (219 yards-high) slope in Kasei Valles was specifically targeted for scientific investigation by rotating the MGS spacecraft about 7.8o off-nadir in January 2003. The scar left by the landslide reveals layers in the bedrock at the top the slope and shows a plethora of dark-toned, house-sized boulders that rolled down the slope and collected at the base of the landslide scar. A few meteor impact craters have formed on the landslide deposit and within the scar, indicating that this landslide occurred a very long time ago. Sunlight illuminates this scene from the left/lower left; the landslide is located near 28.3oN, 71.9oW.

A preliminary regional assessment of earthquake-induced landslide susceptibility for Vrancea Seismic Region

NASA Astrophysics Data System (ADS)

Micu, Mihai; Balteanu, Dan; Ionescu, Constantin; Havenith, Hans; Radulian, Mircea; van Westen, Cees; Damen, Michiel; Jurchescu, Marta

2015-04-01

In seismically-active regions, earthquakes may trigger landslides enhancing the short-to-long term slope denudation and sediment delivery and conditioning the general landscape evolution. Co-seismic slope failures present in general a low frequency - high magnitude pattern which should be addressed accordingly by landslide hazard assessment, with respect to the generally more frequent precipitation-triggered landslides. The Vrancea Seismic Region, corresponding to the curvature sector of the Eastern Romanian Carpathians, represents the most active sub-crustal (focal depth > 50 km) earthquake province of Europe. It represents the main seismic energy source throughout Romania with significant transboundary effects recorded as far as Ukraine and Bulgaria. During the last 300 years, the region featured 14 earthquakes with M>7, among which seven events with magnitude above 7.5 and three between 7.7 and 7.9. Apart from the direct damages, the Vrancea earthquakes are also responsible for causing numerous other geohazards, such as ground fracturing, groundwater level disturbances and possible deep-seated landslide occurrences (rock slumps, rock-block slides, rock falls, rock avalanches). The older deep-seated landslides (assumed to have been) triggered by earthquakes usually affect the entire slope profile. They often formed landslide dams strongly influencing the river morphology and representing potential threats (through flash-floods) in case of lake outburst. Despite the large potential of this research issue, the correlation between the region's seismotectonic context and landslide predisposing factors has not yet been entirely understood. Presently, there is a lack of information provided by the geohazards databases of Vrancea that does not allow us to outline the seismic influence on the triggering of slope failures in this region. We only know that the morphology of numerous large, deep-seated and dormant landslides (which can possibly be reactivated in future

Landslide!

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-486, 17 September 2003

This August 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows part of a deposit created by a landslide off the wall of a crater near 12.3oN, 21.3oW. The crater wall is not shown; it is several kilometers to the left of this picture. The debris that slid from the crater wall came from the left/upper left (northwest) and moved toward the lower right (southeast). The crater floor onto which the debris was deposited has more small meteor craters on it than does the landslide material; this indicates that there was a considerable interval between the time when the crater floor formed, and when the landslide occurred. This picture covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

Dam Breach Release of Non-Cohesive Sediments: Channel Response and Recovery Rates

NASA Astrophysics Data System (ADS)

Collins, M. J.; Boardman, G.; Banks, W.; Andrews, M.; Conlon, M.; Dillow, J. J. A.; Gellis, A.; Lowe, S.; McClain, S.; Miller, A. J.; Snyder, N. P.; Wilcock, P. R.

2014-12-01

Dam removals featuring unchecked releases of non-cohesive sediments are excellent opportunities to learn more about stream channel response to abrupt increases in bed material supply that can occur deliberately or by natural processes like landslides and volcanic eruptions. Understanding channel response to sediment pulses, including response rates, is essential because human uses of river channels and floodplains are impacted by these events as are aquatic habitats. We had the opportunity to study a dam removal site at the Simkins Dam in Maryland, USA, that shares many important geophysical attributes of another well-studied dam removal in the humid northeast United States [Merrimack Village Dam, New Hampshire; Pearson et al., 2011]. The watershed sizes are the same order of magnitude (102 km2), and at both sites relatively low head dams were removed (~ 3-4 m) and ~60,000 m3 of dominantly sand-sized sediments discharged to low-gradient reaches immediately downstream. Analyzing four years of repeat morphometry and bed sediment grain size surveys at the Simkins site on the Patapsco River, as well as continuous discharge and suspended sediment gaging data, we clearly document a two-phase response in the upstream reach as described by Pearson et al. [2011] for their New Hampshire site and noted at other dam removals [e.g., Major et al., 2012]. In the early phase, approximately 50% of the impounded sediment mass was eroded rapidly over a period of about three months when flows were very modest (Figure 1). After incision to base level and channel widening in the former impoundment, a second phase began when further erosion depended on floods large enough to access impounded sediments more distant from the newly-formed channel. We also found important differences in the upstream responses at the Maryland and New Hampshire sites that appear to be related to valley type (non-glaciated versus glaciated, respectively). Response variances immediately downstream between the

Extreme Precipitation and High-Impact Landslides

NASA Technical Reports Server (NTRS)

Kirschbaum, Dalia; Adler, Robert; Huffman, George; Peters-Lidard, Christa

2012-01-01

It is well known that extreme or prolonged rainfall is the dominant trigger of landslides; however, there remain large uncertainties in characterizing the distribution of these hazards and meteorological triggers at the global scale. Researchers have evaluated the spatiotemporal distribution of extreme rainfall and landslides at local and regional scale primarily using in situ data, yet few studies have mapped rainfall-triggered landslide distribution globally due to the dearth of landslide data and consistent precipitation information. This research uses a newly developed Global Landslide Catalog (GLC) and a 13-year satellite-based precipitation record from Tropical Rainfall Measuring Mission (TRMM) data. For the first time, these two unique products provide the foundation to quantitatively evaluate the co-occurence of precipitation and rainfall-triggered landslides globally. The GLC, available from 2007 to the present, contains information on reported rainfall-triggered landslide events around the world using online media reports, disaster databases, etc. When evaluating this database, we observed that 2010 had a large number of high-impact landslide events relative to previous years. This study considers how variations in extreme and prolonged satellite-based rainfall are related to the distribution of landslides over the same time scales for three active landslide areas: Central America, the Himalayan Arc, and central-eastern China. Several test statistics confirm that TRMM rainfall generally scales with the observed increase in landslide reports and fatal events for 2010 and previous years over each region. These findings suggest that the co-occurrence of satellite precipitation and landslide reports may serve as a valuable indicator for characterizing the spatiotemporal distribution of landslide-prone areas in order to establish a global rainfall-triggered landslide climatology. This research also considers the sources for this extreme rainfall, citing

Analysis of landslide overgrowing rates at Vaskiny Dachi key site, Central Yamal, Russia

NASA Astrophysics Data System (ADS)

Khomutov, A.

2009-04-01

An estimation of overgrowing of landslide-affected slopes by vegetation at three main landslide elements: shear surface, landslide body and "frontal zone" at Vaskiny Dachi key site is presented. Vaskiny Dachi key site is located in the watershed of Se-Yakha and Mordy-Yakha rivers on Central Yamal, Russia. The area is represented by highly-dissected alluvial-lacustrine-marine plains and terraces. The closest to Vaskiny Dachi climate station is Marresale, about 90 km southwest of Vaskiny Dachi, at the Kara sea coast. The weather here is probably somewhat cooler than at Vaskiny Dachi. The average annual (summer) air temperature at Marresale is -8.3° C (4.3° C) ("Russia's Weather" Server). To estimate vegetation cover dynamics on cryogenic landslides at "Vaskiny Dachi", data published by O.Rebristaya and others (1995) were used. Their observations were done in 1991-1993, and were supplemented by further field observations (Leibman et al., 2000, Khomutov & Leibman 2007) and by field and remote sensing observations in 2008. An estimation of vegetation cover dynamics on cryogenic landslides at "Vaskiny Dachi" leads to the following results. Immediately after landsliding in 1989, landslide shear surface was bare without any vegetation, landslide body had initial vegetation, and "frontal zone" was under liquefied sediment masses. "Frontal zone" formed in front of a landslide body, appears as a result of damming of drainage routes by a landslide body with flooding of the shear surface "upstream" of the landslide body, formation of a sedge-cottongrass meadow there, and swamping downstream (Khomutov & Leibman 2007). By 1993, landslide shear surface got overgrown by species subordinate in surrounding initial landscapes (Alopecurus alpinus, Festuca ovina, Calamagrostis neglecta, Poa alpigena ssp. Alpigena, etc.). Landslide body was covered by initial communities which got depressed: vitality of Salix polaris, Vaccinium vitis-idaea was reduced, dead off moss cover and overgrown

Landslides in Valles Marineris, Mars

NASA Technical Reports Server (NTRS)

Lucchitta, B. K.

1979-01-01

The morphology of the landslides in the Martian equatorial troughs, the geologic structure of the troughs, the time of emplacement, the similarity to terrestrial landslides, and the origin and mechanism of transport are analyzed. About 35 large landslides well-resolved on Viking images were examined, and it is found that the major landslides cover 31,000 sq km of the trough floors, and individual slides range in area from 40 to 7000 sq km. The morphologic variations of the landslides can be attributed mainly to their degree of confinement on trough floors. Many prominent landslides appear to be of similar age and were emplaced after a major faulting that dropped the trough floors. Most sliding occurred after the created scarps were dissected into spurs, gullies, and tributary canyons. Emplacement of the landslides approximately coincided with a late episode of major eruptive activity of the Tharsis volcanoes, and it is suggested that the slides may have originated as gigantic mudflows with slump blocks at their heads. The large size of many landslides is due to the fault scarps as high as 7 km on which they formed in the absence of vigorous fluvial erosion. The landslides suggest that Mars is earthlike in some respects, which may be important for further evaluations.

Slumgullion; Colorado’s natural landslide laboratory

USGS Publications Warehouse

Highland, L.M.

1993-01-01

The mountains of Colorado, and the Rocky Mountains in general, have one of the highest levels of landslide hazard in the nation. In a typical year, landslides hazard in the nation. In a typical year, landslides cause several fatalities and millions of dollars in damage to highways, pipelines, buildings, and forests in Colorado. To reduce such losses we need to understand why landslides occur and how they behave once they form. The Slumgullion landslide, an ideal natural laboratory, offers a unique opportunity to carefully observe and monitor the movement of a large, active landslide. In 1990, soon after the State of Colorado assigned high priority to hazard evaluation of the Slumgullion landslide, the USGS began an intensive study as part of its Landslide Hazards Reduction Program. 

Landslides on Ceres

NASA Image and Video Library

2017-04-19

NASA's Dawn spacecraft has revealed many landslides on Ceres, which researchers interpret to have been shaped by a significant amount of water ice. A 2017 study in the journal Nature Geoscience classifies three types of these debris flows. Image 1 (left in the montage) shows an example of "Type I" flow features, which are relatively round and large, have thick "toes" at their ends. They look similar to rock glaciers and icy landslides on Earth. Type I landslides are mostly found at high latitudes, which is also where the most ice is thought to reside near Ceres' surface. Image 2 (center) shows an example of a "Type II" flow feature. Type II features are often thinner and longer than Type I, and are the most common type of landslide on Ceres. They appear more like the avalanches seen on Earth. Image 3 (right) shows an example of a "Type III" flow feature at Datan Crater. The study authors interpret Ceres' Type III landslides to involve melted ice, although scientists do not know if they actually contain liquid water. The authors think Type III landslides are related to impact craters, and may have formed during impact events into the ice on Ceres. The features resemble fluid material ejected from craters in the icy regions of Mars and Jupiter's moon Ganymede. https://photojournal.jpl.nasa.gov/catalog/PIA21471

Fostering the uptake of satellite Earth Observation data for landslide hazard understanding: the CEOS Landslide Pilot

NASA Astrophysics Data System (ADS)

Kirschbaum, Dalia; Malet, Jean-Philippe; Roessner, Sigrid

2017-04-01

Landslides occur around the world, on every continent, and play an important role in the evolution of landscapes. They also represent a serious hazard in many areas of the world. Despite their importance, it has been estimated that past landslide and landslide potential maps cover less than 1% of the slopes in these landmasses. Systematic information on the type, abundance, and distribution of existing landslides is lacking. Even in countries where landslide information is abundant (e.g. Italy), the vast majority of landslides caused by meteorological (intense or prolonged rainfall, rapid snowmelt) or geophysical (earthquake) triggers go undetected. This paucity of knowledge has consequences on the design of effective remedial and mitigation measures. Systematic use of Earth observation (EO) data and technologies can contribute effectively to detect, map, and monitor landslides, and landslide prone hillsides, in different physiographic and climatic regions. The CEOS (Committee on Earth Observation Satellites) Working Group on Disasters has recently launched a Landslide Pilot (period 2017-2019) with the aim to demonstrate the effective exploitation of satellite EO across the full cycle of landslide disaster risk management, including preparedness, response, and recovery at global, regional, and local scales, with a distinct multi-hazard focus on cascading impacts and risks. The Landslide Pilot is focusing efforts on three objectives: 1. Establish effective practices for merging different Earth Observation data (e.g. optical and radar) to better monitor and map landslide activity over time and space. 2. Demonstrate how landslide products, models, and services can support disaster risk management for multi-hazard and cascading landslide events. 3. Engage and partner with data brokers and end users to understand requirements and user expectations and get feedback through the activities described in objectives 1-2. The Landslide Pilot was endorsed in April 2016 and work

Monitoring Strategies of Earth Dams by Ground-Based Radar Interferometry: How to Extract Useful Information for Seismic Risk Assessment.

PubMed

Di Pasquale, Andrea; Nico, Giovanni; Pitullo, Alfredo; Prezioso, Giuseppina

2018-01-16

The aim of this paper is to describe how ground-based radar interferometry can provide displacement measurements of earth dam surfaces and of vibration frequencies of its main concrete infrastructures. In many cases, dams were built many decades ago and, at that time, were not equipped with in situ sensors embedded in the structure when they were built. Earth dams have scattering properties similar to landslides for which the Ground-Based Synthetic Aperture Radar (GBSAR) technique has been so far extensively applied to study ground displacements. In this work, SAR and Real Aperture Radar (RAR) configurations are used for the measurement of earth dam surface displacements and vibration frequencies of concrete structures, respectively. A methodology for the acquisition of SAR data and the rendering of results is described. The geometrical correction factor, needed to transform the Line-of-Sight (LoS) displacement measurements of GBSAR into an estimate of the horizontal displacement vector of the dam surface, is derived. Furthermore, a methodology for the acquisition of RAR data and the representation of displacement temporal profiles and vibration frequency spectra of dam concrete structures is presented. For this study a Ku-band ground-based radar, equipped with horn antennas having different radiation patterns, has been used. Four case studies, using different radar acquisition strategies specifically developed for the monitoring of earth dams, are examined. The results of this work show the information that a Ku-band ground-based radar can provide to structural engineers for a non-destructive seismic assessment of earth dams.

Analysis of the Tangjiaxi landslide-generated waves in the Zhexi Reservoir, China, by a granular flow coupling model

NASA Astrophysics Data System (ADS)

Huang, Bolin; Yin, Yueping; Wang, Shichang; Tan, Jianmin; Liu, Guangning

2017-05-01

A rocky granular flow is commonly formed after the failure of rocky bank slopes. An impulse wave disaster may also be initiated if the rocky granular flow rushes into a river with a high velocity. Currently, the granular mass-water body coupling study is an important trend in the field of landslide-induced impulse waves. In this paper, a full coupling numerical model for landslide-induced impulse waves is developed based on a non-coherent granular flow equation, i.e., the Mih equation. In this model, the Mih equation for continuous non-coherent granular flow controls movements of sliding mass, the two-phase flow equation regulates the interaction between sliding mass and water, and the renormalization group (RNG) turbulence model governs the movement of the water body. The proposed model is validated and applied for the 2014 Tangjiaxi landslide of the Zhexi Reservoir located in Hunan Province, China, to analyze the characteristics of both landslide motion and its following impulse waves. On 16 July 2014, a rocky debris flow was formed after the failure of the Tangjiaxi landslide, damming the Tangjiaxi stream and causing an impulse wave disaster with three dead and nine missing bodies. Based on the full coupling numerical analysis, the granular flow impacts the water with a maximum velocity of about 22.5 m s-1. Moreover, the propagation velocity of the generated waves reaches up to 12 m s-1. The maximum calculated run-up of 21.8 m is close enough to the real value of 22.7 m. The predicted landslide final deposit and wave run-up heights are in a good agreement with the field survey data. These facts verify the ability of the proposed model for simulating the real impulse wave generated by rocky granular flow events.

A multi-annual landslide inventory for the assessment of shallow landslide susceptibility - Two test cases in Vorarlberg, Austria

NASA Astrophysics Data System (ADS)

Zieher, Thomas; Perzl, Frank; Rössel, Monika; Rutzinger, Martin; Meißl, Gertraud; Markart, Gerhard; Geitner, Clemens

2016-04-01

Geomorphological landslide inventories provide crucial input data for any study on the assessment of landslide susceptibility, hazard or risk. Several approaches for assessing landslide susceptibility have been proposed to identify areas particularly vulnerable to this natural hazard. What they have in common is the need for data of observed landslides. Therefore the first step of any study on landslide susceptibility is usually the compilation of a geomorphological landslide inventory using a geographical information system. Recent research has proved the feasibility of orthophoto interpretation for the preparation of an inventory aimed at the delineation of landslides with the use of distinctive signs in the imagery data. In this study a multi-annual landslide inventory focusing on shallow landslides (i.e. translational soil slides of 0-2 m in depth) was compiled for two study areas in Vorarlberg (Austria) from the interpretation of nine orthophoto series. In addition, derivatives of two generations of airborne laser scanning data aided the mapping procedure. Landslide scar areas were delineated on the basis of a high-resolution differential digital terrain model. The derivation of landslide volumes, depths and depth-to-length ratios are discussed. Results show that most mapped landslides meet the definition of a shallow landslide. The inventory therefore provides the data basis for the assessment of shallow landslide susceptibility and allows for the application of various modelling techniques.

Submarine Landslides: A Multidisciplinary Crossroad

NASA Astrophysics Data System (ADS)

Moscardelli, L. G.

2014-12-01

The study of submarine landslides has advanced considerably in the last decade. A multitude of geoscience disciplines, including marine, petroleum and planetary geology, as well as geohazard assessments, are concerned with the study of these units. Oftentimes, researchers working in these fields disseminate their findings within their own communities and a multidisciplinary approach seems to lack. This presentation showcases several case studies in which a broader approach has increased our understanding of submarine landslides in a variety of geologic settings. Three-dimensional seismic data from several continental margins (Trinidad, Brazil, Morocco, Canada, GOM), as well as data from outcrop localities are shown to explore geomorphological complexities associated with submarine landslides. Discussion associated with the characterization and classification of submarine landslides is also part of this work. Topics that will be cover include: 1) how data from conventional oil and gas exploration activities can be used to increase our understanding of the dynamic behavior of submarine landslides, 2) analogies between terrestrial submarine landslides and potential Martian counterparts, 3) impact of submarine landslides in margin construction, as well as their economic significance and 4) the importance of quantifying the morphology of submarine landslides in a systematic fashion.

Effects of land-use changes on landslides in a landslide-prone area (Ardesen, Rize, NE Turkey).

PubMed

Karsli, F; Atasoy, M; Yalcin, A; Reis, S; Demir, O; Gokceoglu, C

2009-09-01

Various natural hazards such as landslides, avalanches, floods and debris flows can result in enormous property damages and human casualties in Eastern Black Sea region of Turkey. Mountainous topographic character and high frequency of heavy rain are the main factors for landslide occurrence in Ardesen, Rize. For this reason, the main target of the present study is to evaluate the landslide hazards using a sequence of historical aerial photographs in Ardesen (Rize), Turkey, by Photogrammetry and Geographical Information System (GIS). Landslide locations in the study area were identified by interpretation of aerial photographs dated in 1973 and 2002, and by field surveys. In the study, the selected factors conditioning landslides are lithology, slope gradient, slope aspect, vegetation cover, land class, climate, rainfall and proximity to roads. These factors were considered as effective on the occurrence of landslides. The areas under landslide threat were analyzed and mapped considering the landslide conditioning factors. Some of the conditioning factors were investigated and estimated by employing visual interpretation of aerial photos and topographic data. The results showed that the slope, lithology, terrain roughness, proximity to roads, and the cover type played important roles on landslide occurrence. The results also showed that degree of landslides was affected by the number of houses constructed in the region. As a consequence, the method employed in the study provides important benefits for landslide hazard mitigation efforts, because a combination of both photogrammetric techniques and GIS is presented.

Landslide Economics: Concepts and Case Studies

NASA Astrophysics Data System (ADS)

Klose, Martin; Damm, Bodo

2015-04-01

Landslide economics is vital for fundamental understanding of landslide risk as dealing with two important topics: (i) impact assessment, either as damage statistics or cost modeling, and (ii) vulnerability assessment, i.e., the study of exposure, sensitivity, and resilience to landslide damage, ideally from both sociotechnical and financial perspective (e.g., Crovelli and Coe, 2009; Wills et al., 2014). Many aspects addressed in landslide economics have direct influence on landslide risk, including: (i) human activity is often a major causative factor of landslides, not only by predisposing or triggering them, but also as a result of inadequate (low-cost) landslide mitigation; (ii) the level of tolerable or acceptable risk, a measure driving a large part of landslide costs in industrialized countries, is highly variable, differing between individuals, public or private organizations, and societies, with its nature being to change over time; and (iii) decision makers are faced with finding the right balance in landslide mitigation, thus need to weight diverse geological and socioeconomic factors that control its effectiveness in both technical and financial terms (e.g., Klose et al., 2014a). A large part of the complexity in assessing landslide risk as measured by economic costs is due to unique problems in understanding of (i) what types of landslide damage affect human activity and infrastructure in which way, (ii) how society contributes and responds to various kinds of damage, and (iii) how landslide damage is valued in monetary terms. Landslide economics shows the potential to take account of these sociocultural factors to the benefit of risk analysis (e.g., Klose et al., 2014b). The present contribution introduces local and regional case studies in which different economic issues of landslide risk are highlighted using the example of public infrastructures in NW Germany. A special focus is on the following topics: (i) risk culture and created risk, (ii

Large landslides from oceanic volcanoes

USGS Publications Warehouse

Holcomb, R.T.; Searle, R.C.

1991-01-01

Large landslides are ubiquitous around the submarine flanks of Hawaiian volcanoes, and GLORIA has also revealed large landslides offshore from Tristan da Cunha and El Hierro. On both of the latter islands, steep flanks formerly attributed to tilting or marine erosion have been reinterpreted as landslide headwalls mantled by younger lava flows. These landslides occur in a wide range of settings and probably represent only a small sample from a large population. They may explain the large volumes of archipelagic aprons and the stellate shapes of many oceanic volcanoes. Large landslides and associated tsunamis pose hazards to many islands. -from Authors

Ganges Chasma Landslide

NASA Image and Video Library

2002-05-21

This image from NASA Mars Odyssey spacecraft shows a spectacular landslide along a portion of the southern wall of Ganges Chasma within Valles Marineris. Landslides have very characteristic morphologies on Earth, which they also display on Mars.

Connectivity of earthquake-triggered landslides with the fluvial network: Implications for landslide sediment transport after the 2008 Wenchuan earthquake

NASA Astrophysics Data System (ADS)

Li, Gen; West, A. Joshua; Densmore, Alexander L.; Hammond, Douglas E.; Jin, Zhangdong; Zhang, Fei; Wang, Jin; Hilton, Robert G.

2016-04-01

Evaluating the influence of earthquakes on erosion, landscape evolution, and sediment-related hazards requires understanding fluvial transport of material liberated in earthquake-triggered landslides. The location of landslides relative to river channels is expected to play an important role in postearthquake sediment dynamics. In this study, we assess the position of landslides triggered by the Mw 7.9 Wenchuan earthquake, aiming to understand the relationship between landslides and the fluvial network of the steep Longmen Shan mountain range. Combining a landslide inventory map and geomorphic analysis, we quantify landslide-channel connectivity in terms of the number of landslides, landslide area, and landslide volume estimated from scaling relationships. We observe a strong spatial variability in landslide-channel connectivity, with volumetric connectivity (ξ) ranging from ~20% to ~90% for different catchments. This variability is linked to topographic effects that set local channel densities, seismic effects (including seismogenic faulting) that regulate landslide size, and substrate effects that may influence both channelization and landslide size. Altogether, we estimate that the volume of landslides connected to channels comprises 43 + 9/-7% of the total coseismic landslide volume. Following the Wenchuan earthquake, fine-grained (<~0.25 mm) suspended sediment yield across the Longmen Shan catchments is positively correlated to catchment-wide landslide density, but this correlation is statistically indistinguishable whether or not connectivity is considered. The weaker-than-expected influence of connectivity on suspended sediment yield may be related to mobilization of fine-grained landslide material that resides in hillslope domains, i.e., not directly connected to river channels. In contrast, transport of the coarser fraction (which makes up >90% of the total landslide volume) may be more significantly affected by landslide locations.

Assessing the Agreement Between Eo-Based Semi-Automated Landslide Maps with Fuzzy Manual Landslide Delineation

NASA Astrophysics Data System (ADS)

Albrecht, F.; Hölbling, D.; Friedl, B.

2017-09-01

Landslide mapping benefits from the ever increasing availability of Earth Observation (EO) data resulting from programmes like the Copernicus Sentinel missions and improved infrastructure for data access. However, there arises the need for improved automated landslide information extraction processes from EO data while the dominant method is still manual delineation. Object-based image analysis (OBIA) provides the means for the fast and efficient extraction of landslide information. To prove its quality, automated results are often compared to manually delineated landslide maps. Although there is awareness of the uncertainties inherent in manual delineations, there is a lack of understanding how they affect the levels of agreement in a direct comparison of OBIA-derived landslide maps and manually derived landslide maps. In order to provide an improved reference, we present a fuzzy approach for the manual delineation of landslides on optical satellite images, thereby making the inherent uncertainties of the delineation explicit. The fuzzy manual delineation and the OBIA classification are compared by accuracy metrics accepted in the remote sensing community. We have tested this approach for high resolution (HR) satellite images of three large landslides in Austria and Italy. We were able to show that the deviation of the OBIA result from the manual delineation can mainly be attributed to the uncertainty inherent in the manual delineation process, a relevant issue for the design of validation processes for OBIA-derived landslide maps.

Vulnerability of Karangkates dams area by means of zero crossing analysis of data magnetic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sunaryo,, E-mail: sunaryo@ub.ac.id, E-mail: sunaryo.geofis.ub@gmail.com; Susilo, Adi

2015-04-24

located at about 6 km to the west of the Lahor dam approximately. These shown a possible of vulnerability on geohazards at the west zone of the Karangkates (Lahor-Sutami) dams area if there are triggers by the vibration (earthquake) on the Pohgajih shear fault, andesite-limestone contact plane, and instability rocks on two zones of closed closure dipole pairs area. Reality, on the location of the study shown some local landslide at the several locations and the main road that need considering for disaster mitigation.« less

Prediction of the run out extents of the Slano Blato landslide for future debris flow events

NASA Astrophysics Data System (ADS)

Askarinejad, Amin; Leu, Pascal; Macek, Matej; Petkovsek, Ana; Springman, Sarah

2013-04-01

The Slano Blato landslide has a volume of about 1 mio m3 and is located in the western part of Slovenia. It has been considered to be a potential natural hazard for the village of Lokavec for more than 200 years. Several mud flows, exhibiting a range of volumes and velocities, have originated from the landslide body since the year 2000, when the landslide was reactivated due to an intense rainfall event. A series of obstacles, including safety dams and deposition ponds, have been constructed for the remediation of the landslide. These obstacles are designed to absorb and contain future debris flow hazard. A prerequisite to any risk analysis is to establish the vulnerability to the hazard event. The aim of this work is to simulate possible future debris flow scenarios in order to predict the run out distances, flow heights, impact pressures and potential effects on the downstream village buildings and infrastructure. The simulations were carried out using the RAMMS program (RApid Mass MovementS, www.ramms.slf.ch). A three dimensional terrain model of the landslide area and the downstream zones, with or without the inclusion of the obstacles, was made for the simulations and different scenarios concerning the released volume, the internal friction and viscosity of the sliding mass were studied. The results indicate that low viscosity mudflows with a volume of 5,000 m3 endanger some parts of Lokavec village. However, the simulations with volumes of 15,000 and 50,000 m3 predict catastrophic effects in terms of either impact pressures or deposition heights for the majority of houses. Moreover, the simulations confirmed that the choice of the material properties (internal friction and viscosity), the characteristics of the release hydrograph, event location, and natural or man-made obstacles play major roles in the run out distances and impact pressures.

Landslide hazard and forest fires - the relevance of geology for landslide type and development

NASA Astrophysics Data System (ADS)

Fernandez-Steeger, Tomas M.; Wiatr, Thomas; Papanikolaou, Ioannis; Reicherter, Klaus

2010-05-01

Current research indicates an increasing number of forest fires incidents and burned areas for Europe in the future (e.g. Moriondo et al., 2006). Besides economical and environmental impacts they can cause future "secondary" hazards like landslides, debris flows and flash floods. There are many past and current studies investigating effects of erosion and landslide phenomena like debris flows in burned areas (s. Shakesby & Doerr, 2006). The influence of the geological framework is often neglected in these studies. Furthermore, deep seated landslides and slumps are only hypothetically described (Swanson, 1981). To study the relevance of geology and to observe the processes, areas in Attica and the western Peloponnese in Greece burned by the catastrophic wildfires of 2007 and 2009 were investigated. The Tertiary Flysch units and the Neogene deposits in the Pyrgos area of the western Peloponnese are generally a landslide prone area. The slopes in the area show the typical morphological features of a landslide landscape. This is not only true for the in 2007 burned areas but also for unburned areas even in some kilometre distance. Large rotational slides with 20 m and higher main scarps interact and build up complex staircase landslide cascades. Even so vegetation indicates for the unburned areas currently a low activity. In contrary in the burned areas even 2 years after the fires many recent effects from landslides can be observed, like slope failures, cliff break ups, road failures, destroyed retention walls and cracks in houses. While the shallow landslides show a very high dynamic, also older larger landslides are developing or reactivating. As the changes in landslide activity are limited to the burned areas, it is reasonable that the changes in the hydrological conditions like Swanson (1981) predicted due to the destroyed vegetation are the main trigger mechanism for the new and reactivated landslides. An increased availability of water at the sliding plane and

The Manti, Utah, landslide

USGS Publications Warehouse

Fleming, R.W.; Johnson, R.B.; Schuster, R.L.; Williams, G.P.

1988-01-01

PART A: The Manti landslide is in Manti Canyon on the west side of the Wasatch Plateau in central Utah. In early June 1974, coincident with the melting of a snowpack, a rock slump/debris flow occurred on the south rim of Manti Canyon. Part of the slumped material mixed with meltwater and mobilized into a series of debris flows that traveled down the slope a distance of as much as 1.2 km. Most of the flows were deposited either at the base of the steep rocks of the canyon rim or at the site of an old, silted reservoir. A small part of the debris flow deposit stopped on the head of the very large, relatively inactive Manti landslide. The upper part of the landslide began moving as cracks propagated downslope. A little more than a year later, August 1975, movement extended the full length of the old landslide, and about 19 million m 3 of debris about 3 km long and as much as 800 m wide threatened to block the canyon. The upper part of the landslide apparently had moved small amounts between 1939 and 1974. This part of the landslide, identifiable on pre-1974 aerial photographs, consisted of well-defined linears on the landslide flanks and two large internal toe bulges about 2 km downslope from the head. The abrupt reactivation in 1974 proceeded quickly after the debris flows had provided a surcharge in the head and crown area. Movement propagated downslope at 4-5 m/h for the first few days following reactivation. During 1974, the reactivation probably encompassed all the parts of the landslide that had moved small amounts between 1939 and 1974. Movement nearly or completely stopped during the winter of 1974-75, but began again in the spring of 1975. The landslide enlarged from the flanks of the internal toe bulges to Manti Creek at a rate of 2-3 m/h. Movement stopped again during the winter of 1975-76 and began again in the spring of 1976. Thereafter, the displacements have been small compared to earlier. The displacement rates for the landslide were variable depending

Landslide incidence in the North of Portugal: Analysis of a historical landslide database based on press releases and technical reports

NASA Astrophysics Data System (ADS)

Pereira, Susana; Zêzere, José Luís; Quaresma, Ivânia Daniela; Bateira, Carlos

2014-06-01

This work presents and explores the Northern Portugal Landslide Database (NPLD) for the period 1900-2010. NPLD was compiled from press releases (regional and local newspapers) and technical reports (reports by civil protection authorities and academic works); it includes 628 landslides, corresponding to 5.7 landslides per year on average. Although 50% of landslides occurred in the last 35 years of the series, the temporal distribution of landslides does not show any regular increase with time. The relationship between annual precipitation and landslide occurrence shows that reported landslides tend to be more frequent in wetter years. Moreover, landslides occur mostly in the wettest months of the year (December, January and February), which reflects the importance of rainfall in triggering slope instability. Most landslides cause damage that affects people and/or structures; 69.4% of the landslides in Northern Portugal caused 136 fatalities, 173 injured and left 460 persons homeless. More than half of the total landslides (321 landslides) led to railway or motorway closures and 49 landslides destroyed 126 buildings. The NPLD is compared with a landslide database for the whole of Portugal constructed from a single daily national newspaper covering the same reference period. It will be demonstrated that the regional and local newspapers are more effective than the national newspaper in reporting damaging landslides in the North of Portugal. Like other documentary-based landslide inventories, the NPLD does not accurately report non-damaging landslides. Therefore, NPLD was found unsuitable to validate municipal-scale landslide susceptibility models derived from detailed geomorphology-based landslide inventories.

Landslide prediction system in Slovenia (Masprem)

NASA Astrophysics Data System (ADS)

Šinigoj, Jasna; Jemec Auflič, Mateja; Krivic, Matija

2017-04-01

The landslide prediction system MASPREM has been developed in 2013 to (1) predict rainfall induced landslides on national and local level and (2) inform Civil Protection agency and inhabitants of an increased probability of landslide occurrences. A landslide prediction system on national level integrates three major components: (1) a landslide susceptibility map; (2) landslide triggering rainfall threshold values and (3) precipitation forecasting model's (i.e., ALADIN, INCA). Landslide prediction is also calculated on a local level, including exposure maps of inhabitants, buildings and different types of infrastructure to potential landslide occurrence at a scale of 1: 25,000 for 14 selected municipalities. MASPREM system runs in a 12 hour cycling mode, for 24 hours ahead. The results of the probability of landslide models are classified into five classes, with values ranging from one to five; where class one represents areas with a negligible landslide probability and class five areas with a very high landslide probability. It is a fully automated system based on open source software (PostgreSQL) and web applications for displaying results (Java, GDAL). When precipitation forecasting models are transferred to the GeoZS server the conversion process to raster data starts, stores data in a PostgreSQL database and performs the calculation. Based on final results, the WMS service that is responsible for the distribution of data through the service for download and review of results in a web application is created. In the period, from September 2013 to August 2016, MASPREM gave an alert about the probability of landslide occurrences in 84 cases. While the system has potential to become operational in use after the validation phase, there are also limitations related to the input data that should not be neglected: spatial resolution of the ALADIN model, the incomplete landslide inventory that is important for the validation, defining how many days of antecedent rainfall

Beyond the angle of repose: A review and synthesis of landslide processes in response to rapid uplift, Eel River, Northern California

NASA Astrophysics Data System (ADS)

Roering, Joshua J.; Mackey, Benjamin H.; Handwerger, Alexander L.; Booth, Adam M.; Schmidt, David A.; Bennett, Georgina L.; Cerovski-Darriau, Corina

2015-05-01

that the characteristic mid-winter timing of earthflow acceleration corresponds with increased suspended concentration values, suggesting that the seasonal onset of landslide motion each year may be reflected in the export of sediments to the continental margin. The vast majority of active slides exhibit gullied surfaces and the gully networks, which are also seasonally active, may facilitate sediment export although the proportion of material produced by this pathway is poorly known. Along Kekawaka Creek, a prominent tributary to the Eel River, new analyses of catchment-averaged erosion rates derived from cosmogenic radionuclides reveal rapid erosion (0.76 mm/yr) below a prominent knickpoint and slower erosion (0.29 mm/yr) upstream. Such knickpoints are frequently observed in Eel tributaries and are usually comprised of massive (> 10 m) interlocking resistant boulders that likely persist in the landscape for long periods of time (> 105 yr). Upstream of these knickpoints, active landslides tend to be less frequent and average slope angles are slightly gentler than in downstream areas, which indicates that landslide density and average slope angle appear to increase with erosion rate. Lastly, we synthesize evidence for the role of large, catastrophic landslides in regulating sediment flux and landscape form. The emergence of resistant blocks within the mélange bedrock has promoted large catastrophic slides that have dammed the Eel River and perhaps generated outburst events in the past. The frequency and impact of these landslide dams likely depend on the spatial and size distributions of resistant blocks relative to the width and drainage area of adjacent valley networks. Overall, our findings demonstrate that landslides within the Eel River catchment do not occur randomly, but instead exhibit spatial and temporal patterns related to baselevel lowering, climate forcing, and lithologic variations. Combined with recent landscape evolution models that incorporate

Effects of a natural dam-break flood on geomorphology and vegetation on the Elwha River, Washington, U.S.A.

USGS Publications Warehouse

Acker, S.A.; Beechie, T.J.; Shafroth, P.B.

2008-01-01

Ephemeral dams caused by landslides have been observed around the world, yet little is known about the effects of their failure on landforms and vegetation. In 1967, a landslide-dam-break flood in a pristine reach of the Elwha River valley filled the former channel and diverted the river. The reach is a reference site for restoration following the planned removal of dams on the river. We identified five surfaces on the 25 ha debris fan deposited by the flood. Based on tree ages and historic air photos, three of the surfaces formed in 1967, while two formed later. The surfaces varied in substrate (silt and sand, to boulders), and height above the river channel. Tree mortality resulted from tree removal and burial by sediment, the latter leaving snags and some surviving trees. Tree species composition was generally consistent within each surface. Dominant species included red alder (Alnus rubra) and Sitka willow (Salix sitchensis), alone or in combination, a combination of Douglas-fir (Pseudotsuga menziesii) and black cottonwood (Populus balsamifera ssp. trichocarpa), or a combination of alder and Cottonwood. There were significant differences between surfaces in stem density, basal area, and rate of basal area growth. The large degree of heterogeneity in forest structure, composition, and productivity within a relatively small floodplain feature is in part due to spatial variability in the intensity of a single disturbance event, and in part due to the occurrence of subsequent, smaller events. To recreate natural diversity of riparian forests may require mimicking the variety of physical and biotic habitats that a single, complex disturbance event may create.

Evaluation of Rainfall-induced Landslide Potential

NASA Astrophysics Data System (ADS)

Chen, Y. R.; Tsai, K. J.; Chen, J. W.; Chue, Y. S.; Lu, Y. C.; Lin, C. W.

2016-12-01

Due to Taiwan's steep terrain, rainfall-induced landslides often occur and lead to human causalities and properties loss. Taiwan's government has invested huge reconstruction funds to the affected areas. However, after rehabilitation they still face the risk of secondary sediment disasters. Therefore, this study assessed rainfall-induced landslide potential and spatial distribution in some watersheds of Southern Taiwan to configure reasonable assessment process and methods for landslide potential. This study focused on the multi-year multi-phase heavy rainfall events after 2009 Typhoon Morakot and applied the analysis techniques for the classification of satellite images of research region before and after rainfall to obtain surface information and hazard log data. GIS and DEM were employed to obtain the ridge and water system and to explore characteristics of landslide distribution. A multivariate hazards evaluation method was applied to quantitatively analyze the weights of various hazard factors. Furthermore, the interaction between rainfall characteristic, slope disturbance and landslide mechanism was analyzed. The results of image classification show that the values of coefficient of agreement are at medium-high level. The agreement of landslide potential map is at around 80% level compared with historical disaster sites. The relations between landslide potential level, slope disturbance degree, and the ratio of number and area of landslide increment corresponding heavy rainfall events are positive. The ratio of landslide occurrence is proportional to the value of instability index. Moreover, for each rainfall event, the number and scale of secondary landslide sites are much more than those of new landslide sites. The greater the slope land disturbance, the more likely it is that the scale of secondary landslide become greater. The spatial distribution of landslide depends on the interaction of rainfall patterns, slope, and elevation of the research area.

107. DAM EARTH DIKE SUBMERSIBLE DAMS PLANS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

107. DAM - EARTH DIKE - SUBMERSIBLE DAMS - PLANS & SECTIONS (ML-8-52/3-FS) March 1940 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

Assessment of landslide hazards resulting from the February 13, 2001, El Salvador earthquake; a report to the government of El Salvador and the U. S. Agency for International Development

USGS Publications Warehouse

Baum, Rex L.; Crone, Anthony J.; Escobar, Demetreo; Harp, Edwin L.; Major, Jon J.; Martinez, Mauricio; Pullinger, Carlos; Smith, Mark E.

2001-01-01

On February 13, 2001, a magnitude 6.5 earthquake occurred about 40 km eastsoutheast of the capital city of San Salvador in central El Salvador and triggered thousands of landslides in the area east of Lago de Ilopango. The landslides are concentrated in a 2,500-km2 area and are particularly abundant in areas underlain by thick deposits of poorly consolidated, late Pleistocene and Holocene Tierra Blanca rhyolitic tephras that were erupted from Ilopango caldera. Drainages in the tephra deposits are deeply incised, and steep valley walls failed during the strong shaking. Many drainages are clogged with landslide debris that locally buries the adjacent valley floor. The fine grain-size of the tephra facilitates its easy mobilization by rainfall runoff. The potential for remobilizing the landslide debris as debris flows and in floods is significant as this sediment is transported through the drainage systems during the upcoming rainy season. In addition to thousands of shallow failures, two very large landslides occurred that blocked the Rio El Desague and the Rio Jiboa. The Rio El Desague landslide has an estimated volume of 1.5 million m3, and the Rio Jiboa landslide has an estimated volume of 12 million m3. Field studies indicate that catastrophic draining of the Rio El Desague landslide-dammed lake would pose a minimal flooding hazard, whereas catastrophic draining of the Rio Jiboa lake would pose a serious hazard and warrants immediate action. Construction of a spillway across part of the dam could moderate the impact of catastrophic lake draining and the associated flood. Two major slope failures on the northern side of Volcan San Vicente occurred in the upper reaches of Quebrada Del Muerto and the Quebrada El Blanco. The landslide debris in the Quebrada Del Muerto consists dominantly of blocks of well-lithified andesite, whereas the debris in the Quebrada El Blanco consists of poorly consolidated pyroclastic sediment. The large blocks of lithified rock in

Regional moisture balance control of landslide motion: implications for landslide forecasting in a changing climate

USGS Publications Warehouse

Coe, Jeffrey A.

2012-01-01

I correlated 12 years of annual movement of 18 points on a large, continuously moving, deep-seated landslide with a regional moisture balance index (moisture balance drought index, MBDI). I used MBDI values calculated from a combination of historical precipitation and air temperature data from A.D. 1895 to 2010, and downscaled climate projections using the Intergovernmental Panel on Climate Change A2 emissions scenario for 2011–2099. At the landslide, temperature is projected to increase ~0.5 °C/10 yr between 2011 and 2099, while precipitation decreases at a rate of ~2 mm/10 yr. Landslide movement correlated with the MBDI with integration periods of 12 and 48 months. The correlation between movement and MBDI suggests that the MBDI functions as a proxy for groundwater pore pressures and landslide mobility. I used the correlation to forecast decreasing landslide movement between 2011 and 2099, with the head of the landslide expected to stop moving in the mid-21st century. The MBDI, or a similar moisture balance index that accounts for evapotranspiration, has considerable potential as a tool for forecasting the magnitude of ongoing deep-seated landslide movement, and for assessing the onset or likelihood of regional, deep-seated landslide activity.

Object-based Classification for Detecting Landslides and Stochastic Procedure to landslide susceptibility maps - A Case at Baolai Village, SW Taiwan

NASA Astrophysics Data System (ADS)

Lin, Ying-Tong; Chang, Kuo-Chen; Yang, Ci-Jian

2017-04-01

As the result of global warming in the past decades, Taiwan has experienced more and more extreme typhoons with hazardous massive landslides. In this study, we use object-oriented analysis method to classify landslide area at Baolai village by using Formosat-2 satellite images. We used for multiresolution segmented to generate the blocks, and used hierarchical logic to classified 5 different kinds of features. After that, classification the landslide into different type of landslide. Beside, we use stochastic procedure to integrate landslide susceptibility maps. This study assumed that in the extreme event, 2009 Typhoon Morakot, which precipitation goes to 1991.5mm in 5 days, and the highest landslide susceptible area. The results show that study area's landslide area was greatly changes, most of landslide was erosion by gully and made dip slope slide, or erosion by the stream, especially at undercut bank. From the landslide susceptibility maps, we know that the old landslide area have high potential to occur landslides in the extreme event. This study demonstrates the changing of landslide area and the landslide susceptible area. Keywords: Formosat-2, object-oriented, segmentation, classification, landslide, Baolai Village, SW Taiwan, FS

Landsat applied to landslide mapping

NASA Technical Reports Server (NTRS)

Sauchyn, D. J.; Trench, N. R.

1978-01-01

A variety of features characteristic of rotational landslides may be identified on Landsat imagery. These include tonal mottling, tonal banding, major and secondary scarps, and ponds. Pseudostereoscopic viewing of 9 by 9 in. transparencies was useful for the detailed identification of landslides, whereas 1:250,000 prints enlarged from 70 mm negatives were most suitable for regional analysis. Band 7 is the most useful band for landslide recognition, due to accentuation of ponds and shadows. Examination of both bands 7 and 5, including vegetation information, was found to be most suitable. Although, given optimum terrain conditions, some landslides in Colorado may be recognized, many smaller landslides are not identifiable. Consequently, Landsat is not recommended for detailed regional mapping, or for use in areas similar to Colorado, where alternative (aircraft) imagery is available. However, Landsat may prove useful for preliminary landslide mapping in relatively unknown areas.

Frequency-area distribution of earthquake-induced landslides

NASA Astrophysics Data System (ADS)

Tanyas, H.; Allstadt, K.; Westen, C. J. V.

2016-12-01

Discovering the physical explanations behind the power-law distribution of landslides can provide valuable information to quantify triggered landslide events and as a consequence to understand the relation between landslide causes and impacts in terms of environmental settings of landslide affected area. In previous studies, the probability of landslide size was utilized for this quantification and the developed parameter was called a landslide magnitude (mL). The frequency-area distributions (FADs) of several landslide inventories were modelled and theoretical curves were established to identify the mL for any landslide inventory. In the observed landslide inventories, a divergence from the power-law distribution was recognized for the small landslides, referred to as the rollover, and this feature was taken into account in the established model. However, these analyses are based on a relatively limited number of inventories, each with a different triggering mechanism. Existing definition of the mL include some subjectivity, since it is based on a visual comparison between the theoretical curves and the FAD of the medium and large landslides. Additionally, the existed definition of mL introduces uncertainty due to the ambiguity in both the physical explanation of the rollover and its functional form. Here we focus on earthquake-induced landslides (EQIL) and aim to provide a rigorous method to estimate the mL and total landslide area of EQIL. We have gathered 36 EQIL inventories from around the globe. Using these inventories, we have evaluated existing explanations of the rollover and proposed an alternative explanation given the new data. Next, we propose a method to define the EQIL FAD curves, mL and to estimate the total landslide area. We utilize the total landslide areas obtained from inventories to compare them with our estimations and to validate our methodology. The results show that we calculate landslide magnitudes more accurately than previous methods.

Numerical modeling of landslides and generated seismic waves: The Bingham Canyon Mine landslides

NASA Astrophysics Data System (ADS)

Miallot, H.; Mangeney, A.; Capdeville, Y.; Hibert, C.

2016-12-01

Landslides are important natural hazards and key erosion processes. They create long period surface waves that can be recorded by regional and global seismic networks. The seismic signals are generated by acceleration/deceleration of the mass sliding over the topography. They consist in a unique and powerful tool to detect, characterize and quantify the landslide dynamics. We investigate here the processes at work during the two massive landslides that struck the Bingham Canyon Mine on the 10th April 2013. We carry a combined analysis of the generated seismic signals and the landslide processes computed with a 3D modeling on a complex topography. Forces computed by broadband seismic waveform inversion are used to constrain the study and particularly the force-source and the bulk dynamic. The source time function are obtained by a 3D model (Shaltop) where rheological parameters can be adjusted. We first investigate the influence of the initial shape of the sliding mass which strongly affects the whole landslide dynamic. We also see that the initial shape of the source mass of the first landslide constrains pretty well the second landslide source mass. We then investigate the effect of a rheological parameter, the frictional angle, that strongly influences the resulted computed seismic source function. We test here numerous friction laws as the frictional Coulomb law and a velocity-weakening friction law. Our results show that the force waveform fitting the observed data is highly variable depending on these different choices.

New Methodology for Computing Subaerial Landslide-Tsunamis: Application to the 2015 Tyndall Glacier Landslide, Alaska

NASA Astrophysics Data System (ADS)

George, D. L.; Iverson, R. M.; Cannon, C. M.

2016-12-01

Landslide-generated tsunamis pose significant hazards to coastal communities and infrastructure, but developing models to assess these hazards presents challenges beyond those confronted when modeling seismically generated tsunamis. We present a new methodology in which our depth-averaged two-phase model D-Claw (Proc. Roy. Soc. A, 2014, doi: 10.1098/rspa.2013.0819 and doi:10.1098/rspa.2013.0820) is used to simulate all stages of landslide dynamics and subsequent tsunami generation and propagation. D-Claw was developed to simulate landslides and debris-flows, but if granular solids are absent, then the D-Claw equations reduce to the shallow-water equations commonly used to model tsunamis. Because the model describes the evolution of solid and fluid volume fractions, it treats both landslides and tsunamis as special cases of a more general class of phenomena, and the landslide and tsunami can be simulated as a single-layer continuum with spatially and temporally evolving solid-grain concentrations. This seamless approach accommodates wave generation via mass displacement and longitudinal momentum transfer, the dominant mechanisms producing impulse waves when large subaerial landslides impact relatively shallow bodies of water. To test our methodology, we used D-Claw to model a large subaerial landslide and resulting tsunami that occurred on October, 17, 2015, in Taan Fjord near the terminus of Tyndall Glacier, Alaska. The estimated landslide volume derived from radiated long-period seismicity (C. Stark (2015), Abstract EP51D-08, AGU Fall Meeting) was about 70-80 million cubic meters. Guided by satellite imagery and this volume estimate, we inferred an approximate landslide basal slip surface, and we used material property values identical to those used in our previous modeling of the 2014 Oso, Washington, landslide. With these inputs the modeled tsunami inundation patterns on shorelines compare well with observations derived from satellite imagery.

Landsliding in partially saturated materials

USGS Publications Warehouse

Godt, J.W.; Baum, R.L.; Lu, N.

2009-01-01

[1] Rainfall-induced landslides are pervasive in hillslope environments around the world and among the most costly and deadly natural hazards. However, capturing their occurrence with scientific instrumentation in a natural setting is extremely rare. The prevailing thinking on landslide initiation, particularly for those landslides that occur under intense precipitation, is that the failure surface is saturated and has positive pore-water pressures acting on it. Most analytic methods used for landslide hazard assessment are based on the above perception and assume that the failure surface is located beneath a water table. By monitoring the pore water and soil suction response to rainfall, we observed shallow landslide occurrence under partially saturated conditions for the first time in a natural setting. We show that the partially saturated shallow landslide at this site is predictable using measured soil suction and water content and a novel unified effective stress concept for partially saturated earth materials. Copyright 2009 by the American Geophysical Union.

Assessing Landslide Characteristics and Developing a Landslide Potential Hazard Map in Rwanda and Uganda Using NASA Earth Observations

NASA Astrophysics Data System (ADS)

Sinclair, L.; Conner, P.; le Roux, J.; Finley, T.

2015-12-01

The International Emergency Disasters Database indicates that a total of 482 people have been killed and another 27,530 have been affected by landslides in Rwanda and Uganda, although the actual numbers are thought to be much higher. Data for individual countries are poorly tracked, but hotspots for devastating landslides occur throughout Rwanda and Uganda due to the local topography and soil type, intense rainfall events, and deforestation. In spite of this, there has been little research in this region that utilizes satellite imagery to estimate areas susceptible to landslides. This project utilized Landsat 8 Operational Land Imager (OLI) data and Google Earth to identify landslides that occurred within the study area. These landslides were then added to SERVIR's Global Landslide Catalog (GLC). Next, Landsat 8 OLI, the Tropical Rainfall Measuring Mission (TRMM), the Global Precipitation Measurement (GPM), and Shuttle Radar Topography Mission Version 2 (SRTM V2) data were used to create a Landslide Susceptibility Map. This was combined with population data from the Socioeconomic Data and Applications Center (SEDAC) to create a Landslide Hazard map. A preliminary assessment of the relative performance of GPM and TRMM in identifying landslide conditions was also performed. The additions to the GLC, the Landslide Susceptibility Map, the Landslide Hazard Map, and the preliminary assessment of satellite rainfall performance will be used by SERVIR and the Regional Centre for Mapping of Resources for Development (RCMRD) for disaster risk management, land use planning, and determining landslide conditions and moisture thresholds.

Landslide risk mapping and modeling in China

NASA Astrophysics Data System (ADS)

Li, W.; Hong, Y.

2015-12-01

Under circumstances of global climate change, tectonic stress and human effect, landslides are among the most frequent and severely widespread natural hazards on Earth, as demonstrated in the World Atlas of Natural Hazards (McGuire et al., 2004). Every year, landslide activities cause serious economic loss as well as casualties (Róbert et al., 2005). How landslides can be monitored and predicted is an urgent research topic of the international landslide research community. Particularly, there is a lack of high quality and updated landslide risk maps and guidelines that can be employed to better mitigate and prevent landslide disasters in many emerging regions, including China (Hong, 2007). Since the 1950s, landslide events have been recorded in the statistical yearbooks, newspapers, and monographs in China. As disasters have been increasingly concerned by the government and the public, information about landslide events is becoming available from online news reports (Liu et al., 2012).This study presents multi-scale landslide risk mapping and modeling in China. At the national scale, based on historical data and practical experiences, we carry out landslide susceptibility and risk mapping by adopting a statistical approach and pattern recognition methods to construct empirical models. Over the identified landslide hot-spot areas, we further evaluate the slope-stability for each individual site (Sidle and Hirotaka, 2006), with the ultimate goal to set up a space-time multi-scale coupling system of Landslide risk mapping and modeling for landslide hazard monitoring and early warning.

Landslide hazard assessment: recent trends and techniques.

PubMed

Pardeshi, Sudhakar D; Autade, Sumant E; Pardeshi, Suchitra S

2013-01-01

Landslide hazard assessment is an important step towards landslide hazard and risk management. There are several methods of Landslide Hazard Zonation (LHZ) viz. heuristic, semi quantitative, quantitative, probabilistic and multi-criteria decision making process. However, no one method is accepted universally for effective assessment of landslide hazards. In recent years, several attempts have been made to apply different methods of LHZ and to compare results in order to find the best suited model. This paper presents the review of researches on landslide hazard mapping published in recent years. The advanced multivariate techniques are proved to be effective in spatial prediction of landslides with high degree of accuracy. Physical process based models also perform well in LHZ mapping even in the areas with poor database. Multi-criteria decision making approach also play significant role in determining relative importance of landslide causative factors in slope instability process. Remote Sensing and Geographical Information System (GIS) are powerful tools to assess landslide hazards and are being used extensively in landslide researches since last decade. Aerial photographs and high resolution satellite data are useful in detection, mapping and monitoring landslide processes. GIS based LHZ models helps not only to map and monitor landslides but also to predict future slope failures. The advancements in Geo-spatial technologies have opened the doors for detailed and accurate assessment of landslide hazards.

A computationally fast, reduced model for simulating landslide dynamics and tsunamis generated by landslides in natural terrains

NASA Astrophysics Data System (ADS)

Mohammed, F.

2016-12-01

Landslide hazards such as fast-moving debris flows, slow-moving landslides, and other mass flows cause numerous fatalities, injuries, and damage. Landslide occurrences in fjords, bays, and lakes can additionally generate tsunamis with locally extremely high wave heights and runups. Two-dimensional depth-averaged models can successfully simulate the entire lifecycle of the three-dimensional landslide dynamics and tsunami propagation efficiently and accurately with the appropriate assumptions. Landslide rheology is defined using viscous fluids, visco-plastic fluids, and granular material to account for the possible landslide source materials. Saturated and unsaturated rheologies are further included to simulate debris flow, debris avalanches, mudflows, and rockslides respectively. The models are obtained by reducing the fully three-dimensional Navier-Stokes equations with the internal rheological definition of the landslide material, the water body, and appropriate scaling assumptions to obtain the depth-averaged two-dimensional models. The landslide and tsunami models are coupled to include the interaction between the landslide and the water body for tsunami generation. The reduced models are solved numerically with a fast semi-implicit finite-volume, shock-capturing based algorithm. The well-balanced, positivity preserving algorithm accurately accounts for wet-dry interface transition for the landslide runout, landslide-water body interface, and the tsunami wave flooding on land. The models are implemented as a General-Purpose computing on Graphics Processing Unit-based (GPGPU) suite of models, either coupled or run independently within the suite. The GPGPU implementation provides up to 1000 times speedup over a CPU-based serial computation. This enables simulations of multiple scenarios of hazard realizations that provides a basis for a probabilistic hazard assessment. The models have been successfully validated against experiments, past studies, and field data

HYDROGEOLOGY OF THE THERMAL LANDSLIDE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vantine, J.

1985-01-22

The large Thermal Landslide overlies the initial area of geothermal development at The Geysers. The landslide is waterbearing while the underlying Franciscan formation bedrock units are essentially non-waterbearing except where affected by hydrothermal alteration. Perched ground water moving through the landslide is heated prior to discharge as spring flow.

Coupled dam safety analysis using WinDAM

USDA-ARS?s Scientific Manuscript database

Windows® Dam Analysis Modules (WinDAM) is a set of modular software components that can be used to analyze overtopping and internal erosion of embankment dams. Dakota is an extensive software framework for design exploration and simulation. These tools can be coupled to create a powerful framework...

An analysis of on time evolution of landslide

NASA Astrophysics Data System (ADS)

Tsai, Chienwei; Lien, Huipang

2017-04-01

In recent years, the extreme hydrological phenomenon in Taiwan is obvious. Because the increase of heavy rainfall frequency has resulted in severe landslide disaster, the watershed management is very important and how to make the most effective governance within the limited funds is the key point. In recent years many scholars to develop empirical models said that virtually rainfall factors exist and as long as rainfall conditions are met the minimum requirements of the model, landslide will occur. However, rainfall is one of the elements to the landslide, but not the only one element. Rainfall, geology and earthquake all contributed to the landslide as well. Preliminary research found that many landslides occur at the same location constantly and after repeating landslide, the slope had the characteristic of landslide immunity over time, even if the rainfall exceeded the standard, the landslide could not be triggered in the near term. This study investigated the surface conditions of slope that occur repeated landslide. It is difficult to be the basis of subsequent anti-disaster if making rainfall is the only condition to contribute to the landslide. This study analyzes 50 landslides in 2004 2013. Repeated landslide is defined as existed landslide in satellite images of reference period which it's bare area is shrinking or disappearing gradually but the restoration occur landslide again in some period time. The statistical analysis of the study found that 96% of landslide has repeated landslide and on average repeated landslide occurs 3.4 years in 10 years by one year as the unit. The highest of repeated landslide happened in 2010. It would presume that Typhoon Morakot in 2010 brought torrential rain which suffered southern mountain areas severely so the areas occurred repeated landslide.

Landslide in Coprates

NASA Technical Reports Server (NTRS)

2004-01-01

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows part of a large landslide complex off the north wall of Coprates Chasma in the Valles Marineris trough complex. The wall of Coprates Chasma occupies much of the upper and middle portions of the image; the landslide lobes are on the trough floor in the bottom half of the image. Large boulders the size of houses can be seen on these landslide surfaces. This image is located near 13.9 S, 56.7 W. The picture covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the upper left.

Detecting seasonal landslide movement within the Cascade landslide complex (Washington) using time-series SAR imagery

USGS Publications Warehouse

Hu, Xie; Wang, Teng; Pierson, Thomas C.; Lu, Zhong; Kim, Jin-Woo; Cecere, Thomas H.

2016-01-01

Detection of slow or limited landslide movement within broad areas of forested terrain has long been problematic, particularly for the Cascade landslide complex (Washington) located along the Columbia River Gorge. Although parts of the landslide complex have been found reactivated in recent years, the timing and magnitude of motion have not been systematically monitored or interpreted. Here we apply novel time-series strategies to study the spatial distribution and temporal behavior of the landslide movement between 2007 and 2011 using InSAR images from two overlapping L-band ALOS PALSAR-1 satellite tracks. Our results show that the reactivated part has moved approximately 700 mm downslope during the 4-year observation period, while other parts of the landslide complex have generally remained stable. However, we also detect about 300 mm of seasonal downslope creep in a terrain block upslope of the Cascade landslide complex—terrain previously thought to be stable. The temporal oscillation of the seasonal movement can be correlated with precipitation, implying that seasonal movement here is hydrology-driven. The seasonal movement also has a frequency similar to GPS-derived regional ground oscillations due to mass loading by stored rainfall and subsequent rebound but with much smaller magnitude, suggesting different hydrological loading effects. From the time-series amplitude information on terrain upslope of the headscarp, we also re-evaluate the incipient motion related to the 2008 Greenleaf Basin rock avalanche, not previously recognized by traditional SAR/InSAR methods. The approach used in this study can be used to identify active landslides in forested terrain, to track the seasonal movement of landslides, and to identify previously unknown landslide hazards.

Comparison of non-landslide sampling strategies to counteract inventory-based biases within national-scale statistical landslide susceptibility models

NASA Astrophysics Data System (ADS)

Lima, Pedro; Steger, Stefan; Glade, Thomas

2017-04-01

Landslides can represent a significant threat for people and infrastructure in hilly and mountainous landscapes worldwide. The understanding and prediction of those geomorphic processes is crucial to avoid economic loses or even casualties to people and their properties. Statistical based landslide susceptibility models are well known for being highly reliant on the quality, representativeness and availability of input data. In this context, several studies indicate that the landslide inventory represents the most important input data. However each landslide mapping technique or data collection has its drawbacks. Consequently, biased landslide inventories may be commonly introduced into statistical models, especially at regional or even national scale. It remains to the researcher to be aware of potential limitations and design strategies to avoid or reduce the potential propagation of input data errors and biases influences on the modelling outcomes. Previous studies have proven that such erroneous landslide inventories may lead to unrealistic landslide susceptibility maps. We assume that one possibility to tackle systematic landslide inventory-based biases might be a concentration on sampling strategies that focus on the distribution of non-landslide locations. For this purpose, we test an approach for the Austrian territory that concentrates on a modified non-landslide sampling strategy, instead the traditional applied random sampling. It is expected that the way non-landslide locations are represented (e.g. equally over the area or within those areas where mapping campaigns have been conducted) is important to reduce a potential over- or underestimation of landslide susceptibility within specific areas caused by bias. As presumably each landslide inventory is known to be systematically incomplete, especially in those areas where no mapping campaign was previously conducted. This is also applicable to the one currently available for the Austrian territory

Landslide triggering by rain infiltration

USGS Publications Warehouse

Iverson, Richard M.

2000-01-01

Landsliding in response to rainfall involves physical processes that operate on disparate timescales. Relationships between these timescales guide development of a mathematical model that uses reduced forms of Richards equation to evaluate effects of rainfall infiltration on landslide occurrence, timing, depth, and acceleration in diverse situations. The longest pertinent timescale is A/D0, where D0 is the maximum hydraulic diffusivity of the soil and A is the catchment area that potentially affects groundwater pressures at a prospective landslide slip surface location with areal coordinates x, y and depth H. Times greater than A/D0 are necessary for establishment of steady background water pressures that develop at (x, y, H) in response to rainfall averaged over periods that commonly range from days to many decades. These steady groundwater pressures influence the propensity for landsliding at (x, y, H), but they do not trigger slope failure. Failure results from rainfall over a typically shorter timescale H2/D0 associated with transient pore pressure transmission during and following storms. Commonly, this timescale ranges from minutes to months. The shortest timescale affecting landslide responses to rainfall is √(H/g), where g is the magnitude of gravitational acceleration. Postfailure landslide motion occurs on this timescale, which indicates that the thinnest landslides accelerate most quickly if all other factors are constant. Effects of hydrologic processes on landslide processes across these diverse timescales are encapsulated by a response function, R(t*) = √(t*/π) exp (-1/t*) - erfc (1/√t*), which depends only on normalized time, t*. Use of R(t*) in conjunction with topographic data, rainfall intensity and duration information, an infinite-slope failure criterion, and Newton's second law predicts the timing, depth, and acceleration of rainfall-triggered landslides. Data from contrasting landslides that exhibit rapid, shallow

The late Little Ice Age landslide calamity in North Bohemia: Triggers, impacts and post-landslide development reconstructed from documentary data (case study of the Kozí vrch Hill landslide)

NASA Astrophysics Data System (ADS)

Raška, Pavel; Zábranský, Vilém; Brázdil, Rudolf; Lamková, Jana

2016-02-01

The beginning of the 1770s in the Czech Lands is well documented for its meteorological extremes and their social impacts. However, the effects of these extremes on geomorphic systems and on landslide occurrence and activity in particular have been minimally studied. In this paper, we use a complex set of written and iconographic documentary data to reconstruct the landslide calamity in North Bohemia, with a detailed case study of the Kozí vrch Hill landslide. The landslide calamity of 1770 is the oldest known landslide calamity in this region, including 14 documented events; and its reconstruction may therefore provide important data on landslide frequency, triggers, and impacts during the adverse weather patterns in the last part of the Little Ice Age (LIA). We focus on a case study of the Kozí vrch Hill landslide, and we use the documentary evidence and field techniques to reconstruct its location, extent, topography, kinematics, and triggers. Based on precipitation indices and weather descriptions, the extremely wet and rainy preceding year and the 1769/1770 winter were the major triggering factors that resulted in water saturation of Neogene volcaniclastics underlying the basalt lava flows and their subsequent collapse. Furthermore, we analyse the post-landslide terrain transformation and land use patterns during the 240 years following the landslide to illustrate the persistence of particular landslide features. We conclude that the major transformations, which obscured most of the landslide features, occurred in only the last 50-60 years. Finally, we discuss the role of documentary data and the current methodological advances in their use for the reconstruction of landslide frequency and impacts during the LIA.

Probabilistic assessment of precipitation-triggered landslides using historical records of landslide occurence, Seattle, Washington

USGS Publications Warehouse

Coe, J.A.; Michael, J.A.; Crovelli, R.A.; Savage, W.Z.; Laprade, W.T.; Nashem, W.D.

2004-01-01

Ninety years of historical landslide records were used as input to the Poisson and binomial probability models. Results from these models show that, for precipitation-triggered landslides, approximately 9 percent of the area of Seattle has annual exceedance probabilities of 1 percent or greater. Application of the Poisson model for estimating the future occurrence of individual landslides results in a worst-case scenario map, with a maximum annual exceedance probability of 25 percent on a hillslope near Duwamish Head in West Seattle. Application of the binomial model for estimating the future occurrence of a year with one or more landslides results in a map with a maximum annual exceedance probability of 17 percent (also near Duwamish Head). Slope and geology both play a role in localizing the occurrence of landslides in Seattle. A positive correlation exists between slope and mean exceedance probability, with probability tending to increase as slope increases. Sixty-four percent of all historical landslide locations are within 150 m (500 ft, horizontal distance) of the Esperance Sand/Lawton Clay contact, but within this zone, no positive or negative correlation exists between exceedance probability and distance to the contact.

Mapping landslide susceptibility using data-driven methods.

PubMed

Zêzere, J L; Pereira, S; Melo, R; Oliveira, S C; Garcia, R A C

2017-07-01

Most epistemic uncertainty within data-driven landslide susceptibility assessment results from errors in landslide inventories, difficulty in identifying and mapping landslide causes and decisions related with the modelling procedure. In this work we evaluate and discuss differences observed on landslide susceptibility maps resulting from: (i) the selection of the statistical method; (ii) the selection of the terrain mapping unit; and (iii) the selection of the feature type to represent landslides in the model (polygon versus point). The work is performed in a single study area (Silveira Basin - 18.2km 2 - Lisbon Region, Portugal) using a unique database of geo-environmental landslide predisposing factors and an inventory of 82 shallow translational slides. The logistic regression, the discriminant analysis and two versions of the information value were used and we conclude that multivariate statistical methods perform better when computed over heterogeneous terrain units and should be selected to assess landslide susceptibility based on slope terrain units, geo-hydrological terrain units or census terrain units. However, evidence was found that the chosen terrain mapping unit can produce greater differences on final susceptibility results than those resulting from the chosen statistical method for modelling. The landslide susceptibility should be assessed over grid cell terrain units whenever the spatial accuracy of landslide inventory is good. In addition, a single point per landslide proved to be efficient to generate accurate landslide susceptibility maps, providing the landslides are of small size, thus minimizing the possible existence of heterogeneities of predisposing factors within the landslide boundary. Although during last years the ROC curves have been preferred to evaluate the susceptibility model's performance, evidence was found that the model with the highest AUC ROC is not necessarily the best landslide susceptibility model, namely when terrain

Rainfall Induced Landslides in Puerto Rico (Invited)

NASA Astrophysics Data System (ADS)

Lepore, C.; Kamal, S.; Arnone, E.; Noto, V.; Shanahan, P.; Bras, R. L.

2009-12-01

Landslides are a major geologic hazard in the United States, typically triggered by rainfall, earthquakes, volcanoes and human activity. Rainfall-induced landslides are the most common type in the island of Puerto Rico, with one or two large events per year. We performed an island-wide determination of static landslide susceptibility and hazard assessment as well as dynamic modeling of rainfall-induced shallow landslides in a particular hydrologic basin. Based on statistical analysis of past landslides, we determined that reliable prediction of the susceptibility to landslides is strongly dependent on the resolution of the digital elevation model (DEM) employed and the reliability of the rainfall data. A distributed hydrology model capable of simulating landslides, tRIBS-VEGGIE, has been implemented for the first time in a humid tropical environment like Puerto Rico. The Mameyes basin, located in the Luquillo Experimental Forest in Puerto Rico, was selected for modeling based on the availability of soil, vegetation, topographical, meteorological and historic landslide data. .Application of the model yields a temporal and spatial distribution of predicted rainfall-induced landslides, which is used to predict the dynamic susceptibility of the basin to landslides.

A proposed cell model for multiple-occurrence regional landslide events: Implications for landslide susceptibility mapping

NASA Astrophysics Data System (ADS)

Crozier, M. J.

2017-10-01

Multiple-occurrence regional landslide events (MORLEs) consist of hundreds to thousands of shallow landslides occurring more or less simultaneously within defined areas, ranging from tens to thousands of square kilometres. While MORLEs can be triggered by rainstorms and earthquakes, this paper is confined to those landslide events triggered by rainstorms. Globally, MORLEs occur in a range of geological settings in areas of moderate to steep slopes subject to intense rainstorms. Individual landslides in rainstorm-triggered events are dominantly small, shallow debris and earth flows, and debris and earth slides involving regolith or weathered bedrock. The model used to characterise these events assumes that energy distribution within the event area is represented on the land surface by a cell structure; with maximum energy expenditure within an identifiable core and rapid dissipation concentrically away from the centre. The version of the model presented here has been developed for rainfall-triggered landslide events. It proposes that rainfall intensity can be used to determine different critical landslide response zones within the cell (referred to as core, middle, and periphery zones). These zones are most readily distinguished by two conditions: the proportion of the slope that fails and the particular type of the slope stability factor that assumes dominance in determining specific sites of landslide occurrence. The latter condition means that the power of any slope stability factor to distinguish between stable and unstable sites varies throughout the affected area in accordance with the landslide response zones within the cell; certain factors critical for determining the location of landslide sites in one part of the event area have little influence in other parts of the event area. The implication is that landslide susceptibility maps (and subsequently derived mitigation measures) based on conventional slope stability factors may have only limited validity

Landslides and Landscape Evolution

NASA Astrophysics Data System (ADS)

Densmore, A. L.; Hovius, N.

2017-12-01

Landslides have long been recognised as a major hazard, and are a common product of both large earthquakes and rainstorms. Our appreciation for landslides as agents of erosion and land surface evolution, however, is much more recent. Only in the last twenty years have we come to understand the critical role that landslides play at the landscape scale: in allowing hillslopes to keep pace with fluvial incision, in supplying sediment to channel networks and sedimentary basins, in divide migration, and in setting the basic structure of the landscape. This perspective has been made possible in part by repeat remote sensing and new ways of visualising the land surface, and by extending our understanding of failure processes to the landscape scale; but it is also true that the big jumps in our knowledge have been triggered by large events, such as the 1999 Chi-Chi and 2008 Wenchuan earthquakes. Thanks in part to a relative handful of such case studies, we now have a better idea of the spatial distribution of landslides that are triggered in large events, the volume of sediment that they mobilise, the time scales over which that sediment is mobilised and evacuated, and the overall volume balance between erosion and tectonic processes in the growth of mountainous topography. There remain, however, some major challenges that must still be overcome. Estimates of landslide volume remain highly uncertain, as does our ability to predict the evolution of hillslope propensity to failure after a major triggering event, the movement of landslide sediment (especially the coarse fraction that is transported as bedload), and the impact of landslides on both long-term erosion rates and tectonic processes. The limited range of case studies also means that we struggle to predict outcomes for triggering events in different geological settings, such as loess landscapes or massive lithologies. And the perspective afforded by taking a landscape-scale view has yet to be fully reflected in our

Comparative analysis of rainfall and landslide damage for landslide susceptibility zonation

NASA Astrophysics Data System (ADS)

Petrucci, O.; Pasqua, A. A.

2009-04-01

In the present work we applied a methodology tested in previous works to a regional sector of Calabria (Southern Italy), aiming to obtain a zonation of this area according to the susceptibility to develop landslides, as inferred from the combined analysis of past landslide events and cumulate rainfall which triggered them. The complete series of both historical landslides and daily rainfall have been organised in two databases. For each landslide event, damage, mainly defined in relation to the reimbursement requests sent to the Department of Public Works, has been quantified using a procedure based on a Local Damage Index. Rainfall has been described by the Maximum Return Period of cumulative rainfall recorded during the landslide events. Damage index and population density, presumed to represent the location of vulnerable elements, have been referred to Thiessen polygons associated to rain gauges working at the time of the event. The procedure allowed us to carry out a classification of the polygons composing the study area according to their susceptibility to damage during DHEs. In high susceptibility polygons, severe damage occurs during rainfall characterised by low return periods; in medium susceptibility polygons, maximum return period rainfall and induced damage show equal levels of exceptionality; in low susceptibility polygons, high return period rainfall induces a low level of damage. The results can prove useful in establishing civil defence plans, emergency management, and prioritizing hazard mitigation measures.

Occurrence of Landslides during the Approach of Tropical Cyclone Juliette (2001) to Baja California Sur, Mexico

NASA Astrophysics Data System (ADS)

Antinao, J.; Farfan, L.

2012-12-01

The approach of Tropical Cyclone Juliette to the Baja California Peninsula in September 2001 triggered at least 419 landslides. Most of the landslides were shallow slips and debris slides, of limited areal extent, which were converted rapidly into debris flows to be exported quickly out of the mountain areas towards the lowlands. Main factors affecting landslide occurrence were total storm rainfall and intensity, aspect, geology and vegetation association. Two processes can be distinguished as initiating slope failure. The first process is linked to failures in concave topography, where accumulation of rainfall from exposed bedrock slopes generated excess overland flow that aggregated to generate a 'fire hose' effect on the base of slopes, mobilizing regolith. A second process involved a combination of wind and excess overland flow developed in the more convex or planar upper slopes, where heterogeneous regolith has formed in time following successional changes in vegetation associations along the oak-dry tropical forest ecotone. In this area, wind uprooted trees that dislodged large regolith and bedrock blocks, priming hillslopes for further runoff concentration. From the analysis of historical information, an estimative threshold curve for triggering landslides in this region is sketched. It was also determined that storms like Juliette approach the southern peninsula on average once every 100 years. Denudation estimates are in the higher end of the spectrum for a tectonically passive margin. These estimates should be considered when taking decisions regarding management of water resources in this area through damming of streams. The results emphasize the need for a more detailed representation of the spatial distribution of the rainfall and winds for this mountainous region frequently affected by the passage of tropical cyclones.

Monitoring landslide kinematics by multi-temporal radar interferometry - the Corvara landslide case study

NASA Astrophysics Data System (ADS)

Thiebes, Benni; Cuozzo, Giovanni; Callegari, Mattia; Schlögel, Romy; Mulas, Marco; Corsini, Alessandro; Mair, Volkmar

2016-04-01

Corvara landslide in the Italian Dolomites is slow-moving landslide on which extensive research activities have been carried out since the 1990ies, including sub-surface techniques (e.g. drillings, piezometers and inclinometers), surface methods (e.g. geomorphological mapping and GPS measurements), and remote sensing techniques (e.g. multi-temporal radar interferometry (MTI), and recently amplitude-based offset-tracking and UAV-based photogrammetry). The currently active volume of Corvara landslide has been estimated to be approximately 25 million m³ with shear surfaces at depths of 40 m. Displacement velocities greatly vary spatially and temporally, with only a few cm per year in the accumulation zone, and more than 20 m per year in the highly active source zone. Autumn rainfall and spring snow melt, as well as accumulation of snow during winter have been identified as the major displacement triggering and accelerating events. The ongoing landslide movements pose a threat to the municipality of Corvara, the national road 244, extensive ski resort infrastructure and a golf course. Over the last years, the focus for monitoring the Corvara landslide was put on MTI using 16 artificial corner reflectors and on permanent and periodic differential GPS measurements. This aimed for (1) assessing the ongoing displacements of an active and complex landslide, and (2) analysing the benefits and limitations of MTI for landslide monitoring from the perspective of geomorphologists but also for administrative end-user such as civil protection and Geological surveys. Here, we present the latest results of these analyses, and report on the potential of MTI and related investigations, as well as future fields of research.

Landslides from the February 4, 1976, Guatemala earthquake

USGS Publications Warehouse

Harp, Edwin L.; Wilson, Raymond C.; Wieczorek, Gerald F.

1981-01-01

The M (Richter magnitude) = 7.5 Guatemala earthquake of February 4, 1976, generated more than 10,000 landslides throughout an area of approximately 16,000 km2. These landslides caused hundreds of fatalities as well as extensive property damage. Landslides disrupted both highways and the railroad system and thus severely hindered early rescue efforts. In Guatemala City, extensive property damage and loss of life were due to ground failure beneath dwellings built too close to the edges of steeply incised canyons. We have recorded the distribution of landslides from this earthquake by mapping individual slides at a scale of 1:50,000 for most of the landslide-affected area, using high-altitude aerial photography. The highest density of landslides was in the highlands west of Guatemala City. The predominant types of earthquake-triggered landslides were rock falls and debris slides of less than 15,000 m3 volume; in addition to these smaller landslides, 11 large landslides had volumes of more than 100,000 m3. Several of these large landslides posed special hazards to people and property from lakes impounded by the landslide debris and from the ensuing floods that occurred upon breaching and rapid erosion of the debris. The regional landslide distribution was observed to depend on five major factors: (1) seismic intensity; (2) lithology: 90 percent of all landslides were within Pleistocene pumice deposits; (3) slope steepness; (4) topographic amplification of seismic ground motion; and (5) regional fractures. The presence of preearthquake landslides had no apparent effect on the landslide distribution, and landslide concentration in the Guatemala City area does not correlate with local seismic-intensity data. The landslide concentration, examined at this scale, appears to be governed mainly by lithologic differences within the pumice deposits, preexisting fractures, and amplification of ground motion by topography-all factors related to site conditions.

Ganges Landslide

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] Context image for PIA03681 Ganges Landslide

Two large landslides dominate this image of part of Ganges Chasma. The eroded surface of an old landslide covers the north half of the image, while a more recent landslide occurs to the south.

Image information: VIS instrument. Latitude -6.7N, Longitude 310.4E. 17 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Application of a neuro-fuzzy model to landslide-susceptibility mapping for shallow landslides in a tropical hilly area

NASA Astrophysics Data System (ADS)

Oh, Hyun-Joo; Pradhan, Biswajeet

2011-09-01

This paper presents landslide-susceptibility mapping using an adaptive neuro-fuzzy inference system (ANFIS) using a geographic information system (GIS) environment. In the first stage, landslide locations from the study area were identified by interpreting aerial photographs and supported by an extensive field survey. In the second stage, landslide-related conditioning factors such as altitude, slope angle, plan curvature, distance to drainage, distance to road, soil texture and stream power index (SPI) were extracted from the topographic and soil maps. Then, landslide-susceptible areas were analyzed by the ANFIS approach and mapped using landslide-conditioning factors. In particular, various membership functions (MFs) were applied for the landslide-susceptibility mapping and their results were compared with the field-verified landslide locations. Additionally, the receiver operating characteristics (ROC) curve for all landslide susceptibility maps were drawn and the areas under curve values were calculated. The ROC curve technique is based on the plotting of model sensitivity — true positive fraction values calculated for different threshold values, versus model specificity — true negative fraction values, on a graph. Landslide test locations that were not used during the ANFIS modeling purpose were used to validate the landslide susceptibility maps. The validation results revealed that the susceptibility maps constructed by the ANFIS predictive models using triangular, trapezoidal, generalized bell and polynomial MFs produced reasonable results (84.39%), which can be used for preliminary land-use planning. Finally, the authors concluded that ANFIS is a very useful and an effective tool in regional landslide susceptibility assessment.

Deviation from Power Law Behavior in Landslide Phenomenon

NASA Astrophysics Data System (ADS)

Li, L.; Lan, H.; Wu, Y.

2013-12-01

Power law distribution of magnitude is widely observed in many natural hazards (e.g., earthquake, floods, tornadoes, and forest fires). Landslide is unique as the size distribution of landslide is characterized by a power law decrease with a rollover in the small size end. Yet, the emergence of the rollover, i.e., the deviation from power law behavior for small size landslides, remains a mystery. In this contribution, we grouped the forces applied on landslide bodies into two categories: 1) the forces proportional to the volume of failure mass (gravity and friction), and 2) the forces proportional to the area of failure surface (cohesion). Failure occurs when the forces proportional to volume exceed the forces proportional to surface area. As such, given a certain mechanical configuration, the failure volume to failure surface area ratio must exceed a corresponding threshold to guarantee a failure. Assuming all landslides share a uniform shape, which means the volume to surface area ratio of landslide regularly increase with the landslide volume, a cutoff of landslide volume distribution in the small size end can be defined. However, in realistic landslide phenomena, where heterogeneities of landslide shape and mechanical configuration are existent, a simple cutoff of landslide volume distribution does not exist. The stochasticity of landslide shape introduce a probability distribution of the volume to surface area ratio with regard to landslide volume, with which the probability that the volume to surface ratio exceed the threshold can be estimated regarding values of landslide volume. An experiment based on empirical data showed that this probability can induce the power law distribution of landslide volume roll down in the small size end. We therefore proposed that the constraints on the failure volume to failure surface area ratio together with the heterogeneity of landslide geometry and mechanical configuration attribute for the deviation from power law

Maps Showing Seismic Landslide Hazards in Anchorage, Alaska

USGS Publications Warehouse

Jibson, Randall W.; Michael, John A.

2009-01-01

The devastating landslides that accompanied the great 1964 Alaska earthquake showed that seismically triggered landslides are one of the greatest geologic hazards in Anchorage. Maps quantifying seismic landslide hazards are therefore important for planning, zoning, and emergency-response preparation. The accompanying maps portray seismic landslide hazards for the following conditions: (1) deep, translational landslides, which occur only during great subduction-zone earthquakes that have return periods of =~300-900 yr; (2) shallow landslides for a peak ground acceleration (PGA) of 0.69 g, which has a return period of 2,475 yr, or a 2 percent probability of exceedance in 50 yr; and (3) shallow landslides for a PGA of 0.43 g, which has a return period of 475 yr, or a 10 percent probability of exceedance in 50 yr. Deep, translational landslide hazard zones were delineated based on previous studies of such landslides, with some modifications based on field observations of locations of deep landslides. Shallow-landslide hazards were delineated using a Newmark-type displacement analysis for the two probabilistic ground motions modeled.

Maps showing seismic landslide hazards in Anchorage, Alaska

USGS Publications Warehouse

Jibson, Randall W.

2014-01-01

The devastating landslides that accompanied the great 1964 Alaska earthquake showed that seismically triggered landslides are one of the greatest geologic hazards in Anchorage. Maps quantifying seismic landslide hazards are therefore important for planning, zoning, and emergency-response preparation. The accompanying maps portray seismic landslide hazards for the following conditions: (1) deep, translational landslides, which occur only during great subduction-zone earthquakes that have return periods of =300-900 yr; (2) shallow landslides for a peak ground acceleration (PGA) of 0.69 g, which has a return period of 2,475 yr, or a 2 percent probability of exceedance in 50 yr; and (3) shallow landslides for a PGA of 0.43 g, which has a return period of 475 yr, or a 10 percent probability of exceedance in 50 yr. Deep, translational landslide hazards were delineated based on previous studies of such landslides, with some modifications based on field observations of locations of deep landslides. Shallow-landslide hazards were delineated using a Newmark-type displacement analysis for the two probabilistic ground motions modeled.

Landslides on Charon and not on Pluto

NASA Astrophysics Data System (ADS)

Beyer, Ross A.; Singer, Kelsi N.; Nimmo, Francis; Moore, Jeffrey M.; McKinnon, William B.; Schenk, Paul M.; Spencer, John R.; Weaver, Harold A.; Olkin, Catherine B.; Young, Leslie; Ennico, Kimberly; Stern, S. Alan; New Horizons Science Team

2016-10-01

Landslide features are observed on Charon but not on Pluto. This observation is another that reinforces the different strength regime of surface materials on the two bodies. Pluto's surface, although underlain by strong water ice, is primarily mantled with a variety of geologically weak ice species. Observations of these features indicate that they flow and move, but do so in a manner similar to glacial flow, and the strength and steepening required to precipitate a landslide simply isn't present in these materials under the pressure and temperature conditions on Pluto's surface. There are certainly areas of local mass-wasting, but no substantial landslide deposits. There are some locations on Pluto, notably along the fossae walls, and perhaps on the steeper montes surfaces that could have fostered landslides, but no landslide deposits have been observed nor are there obvious landslide alcoves that would have sourced them. The resolution of observations along the fossae may prevent identification there, and the toes of the steeper montes are embayed by geologically recent plains material which could be overlaying any landslide deposits.Charon, however, has a water-ice surface which exhibits many strength-dominated geologic features, and also exhibits landslide deposits. There are not many of these features and they are confined to the informally named Serenity Chasma, which has relatively steep, tall slopes, perfect for landslide initiation. We will discuss the physical characteristics of these landslide deposits and their context amongst other landslide features in the solar system.

Mechanical-mathematical modeling for landslide process

NASA Astrophysics Data System (ADS)

Svalova, V.

2009-04-01

Landslides process is one of the most widespread and dangerous processes in the urbanized territories. In Moscow the landslips occupy about 3 % of the most valuable territory of city. There are near 20 places of deep landslides and some hundreds of shallow landslides in Moscow. In Russia many towns are located near rivers on high coastal sides. There are many churches and historical buildings on high costs of Volga River and Moscow River. The organization of monitoring is necessary for maintenance of normal functioning of city infrastructure in a coastal zone and duly realization of effective protective actions. Last years the landslide process activization took place in Moscow. The right coast of river Moscow on its significant extent within the limits of city Moscow is struck by deep block landslides with depth up to 90 - 100 m which formation occurred in preglacial time with basis of sliding in Callovian-Oxford clays of Jurassic system on 25 - 30 m below modern level of the river . One of landslide sites is on Vorob'evy mountains, on a high slope of the right coast of the river Moscow with height of 65 m. There is a historical monument - «Andreevsky monastery», based in 1648. Also there are the complex of buildings of Presidium of the Russian Academy of Sciences, constructed in 70 - 80th years of 20-th century, bridge with station of underground "Vorob'evy mountain", constructions of sport complexes. Landslide slope is in active condition, and there are many attributes of activization of deep block landslide. In June 2007 a rather big landslide took place there near ski-jump. Another landslide site is in a southeast part of Moscow, occupying the right coast of river Moscow near museum - reserve "Kolomenskoye". The slope in this place has height of 38 - 40 m. Motions of deep landslips have begun from 1960 in connection with construction of collectors. In 70th years of XX century there was a strong activization of a slope with formation of cracks by extent up to

The Vulnerability of People to Landslides: A Case Study on the Relationship between the Casualties and Volume of Landslides in China.

PubMed

Lin, Qigen; Wang, Ying; Liu, Tianxue; Zhu, Yingqi; Sui, Qi

2017-02-21

The lack of a detailed landslide inventory makes research on the vulnerability of people to landslides highly limited. In this paper, the authors collect information on the landslides that have caused casualties in China, and established the Landslides Casualties Inventory of China . 100 landslide cases from 2003 to 2012 were utilized to develop an empirical relationship between the volume of a landslide event and the casualties caused by the occurrence of the event. The error bars were used to describe the uncertainty of casualties resulting from landslides and to establish a threshold curve of casualties caused by landslides in China. The threshold curve was then applied to the landslide cases occurred in 2013 and 2014. The validation results show that the estimated casualties of the threshold curve were in good agreement with the real casualties with a small deviation. Therefore, the threshold curve can be used for estimating potential casualties and landslide vulnerability, which is meaningful for emergency rescue operations after landslides occurred and for risk assessment research.

The Vulnerability of People to Landslides: A Case Study on the Relationship between the Casualties and Volume of Landslides in China

PubMed Central

Lin, Qigen; Wang, Ying; Liu, Tianxue; Zhu, Yingqi; Sui, Qi

2017-01-01

The lack of a detailed landslide inventory makes research on the vulnerability of people to landslides highly limited. In this paper, the authors collect information on the landslides that have caused casualties in China, and established the Landslides Casualties Inventory of China. 100 landslide cases from 2003 to 2012 were utilized to develop an empirical relationship between the volume of a landslide event and the casualties caused by the occurrence of the event. The error bars were used to describe the uncertainty of casualties resulting from landslides and to establish a threshold curve of casualties caused by landslides in China. The threshold curve was then applied to the landslide cases occurred in 2013 and 2014. The validation results show that the estimated casualties of the threshold curve were in good agreement with the real casualties with a small deviation. Therefore, the threshold curve can be used for estimating potential casualties and landslide vulnerability, which is meaningful for emergency rescue operations after landslides occurred and for risk assessment research. PMID:28230810

Landslide!

ERIC Educational Resources Information Center

Hall-Wallace, Michelle; Mitchell, Carl

1996-01-01

Presents a unit that focuses on landslides and integrates earth science, physics, chemistry, and math. Includes activities to investigate porosity, permeability, cohesion, saturation, and gravity. (JRH)

Landslide Susceptibility Index Determination Using Aritificial Neural Network

NASA Astrophysics Data System (ADS)

Kawabata, D.; Bandibas, J.; Urai, M.

2004-12-01

The occurrence of landslide is the result of the interaction of complex and diverse environmental factors. The geomorphic features, rock types and geologic structure are especially important base factors of the landslide occurrence. Generating landslide susceptibility index by defining the relationship between landslide occurrence and that base factors using conventional mathematical and statistical methods is very difficult and inaccurate. This study focuses on generating landslide susceptibility index using artificial neural networks in Southern Japanese Alps. The training data are geomorphic (e.g. altitude, slope and aspect) and geologic parameters (e.g. rock type, distance from geologic boundary and geologic dip-strike angle) and landslides. Artificial neural network structure and training scheme are formulated to generate the index. Data from areas with and without landslide occurrences are used to train the network. The network is trained to output 1 when the input data are from areas with landslides and 0 when no landslide occurred. The trained network generates an output ranging from 0 to 1 reflecting the possibility of landslide occurrence based on the inputted data. Output values nearer to 1 means higher possibility of landslide occurrence. The artificial neural network model is incorporated into the GIS software to generate a landslide susceptibility map.

Submarine landslides

USGS Publications Warehouse

Hampton, M.A.; Lee, H.J.; Locat, J.

1996-01-01

Landslides are common on inclined areas of the seafloor, particularly in environments where weak geologic materials such as rapidly deposited, finegrained sediment or fractured rock are subjected to strong environmental stresses such as earthquakes, large storm waves, and high internal pore pressures. Submarine landslides can involve huge amounts of material and can move great distances: slide volumes as large as 20,000 km3 and runout distances in excess of 140 km have been reported. They occur at locations where the downslope component of stress exceeds the resisting stress, causing movement along one or several concave to planar rupture surfaces. Some recent slides that originated nearshore and retrogressed back across the shoreline were conspicuous by their direct impact on human life and activities. Most known slides, however, occurred far from land in prehistoric time and were discovered by noting distinct to subtle characteristics, such as headwall scarps and displaced sediment or rock masses, on acoustic-reflection profiles and side-scan sonar images. Submarine landslides can be analyzed using the same mechanics principles as are used for occurrences on land. However, some loading mechanisms are unique, for example, storm waves, and some, such as earthquakes, can have greater impact. The potential for limited-deformation landslides to transform into sediment flows that can travel exceedingly long distances is related to the density of the slope-forming material and the amount of shear strength that is lost when the slope fails.

Operational early warning of shallow landslides in Norway: Evaluation of landslide forecasts and associated challenges

NASA Astrophysics Data System (ADS)

Dahl, Mads-Peter; Colleuille, Hervé; Boje, Søren; Sund, Monica; Krøgli, Ingeborg; Devoli, Graziella

2015-04-01

The Norwegian Water Resources and Energy Directorate (NVE) runs a national early warning system (EWS) for shallow landslides in Norway. Slope failures included in the EWS are debris slides, debris flows, debris avalanches and slush flows. The EWS has been operational on national scale since 2013 and consists of (a) quantitative landslide thresholds and daily hydro-meteorological prognosis; (b) daily qualitative expert evaluation of prognosis / additional data in decision to determine warning levels; (c) publication of warning levels through various custom build internet platforms. The effectiveness of an EWS depends on both the quality of forecasts being issued, and the communication of forecasts to the public. In this analysis a preliminary evaluation of landslide forecasts from the Norwegian EWS within the period 2012-2014 is presented. Criteria for categorizing forecasts as correct, missed events or false alarms are discussed and concrete examples of forecasts falling into the latter two categories are presented. The evaluation show a rate of correct forecasts exceeding 90%. However correct forecast categorization is sometimes difficult, particularly due to poorly documented landslide events. Several challenges has to be met in the process of further lowering rates of missed events of false alarms in the EWS. Among others these include better implementation of susceptibility maps in landslide forecasting, more detailed regionalization of hydro-meteorological landslide thresholds, improved prognosis on precipitation, snowmelt and soil water content as well as the build-up of more experience among the people performing landslide forecasting.

The Springdale, Utah, landslide: An extraordinary event

USGS Publications Warehouse

Jibson, R.W.; Harp, E.L.

1996-01-01

The most dramatic geologic effect of the M-5.7 St. George, Utah earthquake of 2 September 1992 was the triggering of the 14,000,000-m3 Springdale, Utah landslide. The roughly 10 m of landslide movement destroyed three houses, threatened several condominiums, disrupted utility lines, and temporarily closed the southwest entrance to Zion National Park. The seismic triggering of this landslide is puzzling because its distance from the earthquake epicenter, 44 km, is much greater than the farthest distance (18 km) at which similar landslides have been triggered in worldwide earthquakes of the same magnitude. Other Colorado Plateau earthquakes also have produced landslides far beyond worldwide distance limits, which suggests that regional variations in ground-shaking attenuation may require different landslide-triggering distance limits for different seismotectonic regions. Slope stability analysis and historical records of landslide movement suggest that the Springdale landslide was only slightly above limit-equilibrium conditions at the time of the earthquake. Dynamic stability analysis using Newmark's permanent-displacement method indicates coseismic landslide displacement of only 1-8 cm; this rather modest displacement probably induced enough deformation in the montmorillonitic clays along the failure surface to reduce shear strength and destabilize the slide, which continued to move for several hours after the earthquake.

Landslide databases review in the Geological Surveys of Europe

NASA Astrophysics Data System (ADS)

Herrera, Gerardo

2017-04-01

Landslides are one of the most widespread geohazards in Europe, producing significant social and economic damages. Rapid population growth in urban areas throughout many countries in Europe and extreme climatic scenarios can considerably increase landslide risk in the near future. However, many European countries do not include landslide risk into their legislation. Countries lack official methodological assessment guidelines and knowledge about landslide impacts. Although regional and national landslide databases exist in most countries, they are often not integrated because they are owed by different institutions. Hence, a European Landslides Directive, that provides a common legal framework for dealing with landslides, is necessary. With this long-term goal in mind, we present a review of the landslide databases from the Geological Surveys of Europe focusing on their interoperability. The same landslide classification was used for the 849,543 landslide records from the Geological Surveys, from which 36% are slides, 10 % falls, 20% flows, 11% complex slides and 24% remain either unclassified or correspond to another typology. A landslide density map was produced from the available records of the Geological Surveys of 17 countries showing the variable distribution of landslides. There are 0.2 million km2 of landslide prone areas. The comparison of this map with the European landslide susceptibility map ELSUS v1 was successful for 73% of the predictions, and permitted identification of 25% of susceptible areas where landslide records are not available from the Geological Surveys. Taking these results into account the completeness of these landslide databases was evaluated, revealing different landslide hazard management approaches between surveys and countries.

Small-scale loess landslide monitoring with small baseline subsets interferometric synthetic aperture radar technique-case study of Xingyuan landslide, Shaanxi, China

NASA Astrophysics Data System (ADS)

Zhao, Chaoying; Zhang, Qin; He, Yang; Peng, Jianbing; Yang, Chengsheng; Kang, Ya

2016-04-01

Small baseline subsets interferometric synthetic aperture radar technique is analyzed to detect and monitor the loess landslide in the southern bank of the Jinghe River, Shaanxi province, China. Aiming to achieve the accurate preslide time-series deformation results over small spatial scale and abrupt temporal deformation loess landslide, digital elevation model error, coherence threshold for phase unwrapping, and quality of unwrapping interferograms must be carefully checked in advance. In this experience, land subsidence accompanying a landslide with the distance <1 km is obtained, which gives a sound precursor for small-scale loess landslide detection. Moreover, the longer and continuous land subsidence has been monitored while deformation starting point for the landslide is successfully inverted, which is key to monitoring the similar loess landslide. In addition, the accelerated landslide deformation from one to two months before the landslide can provide a critical clue to early warning of this kind of landslide.

Simple scaling of catastrophic landslide dynamics.

PubMed

Ekström, Göran; Stark, Colin P

2013-03-22

Catastrophic landslides involve the acceleration and deceleration of millions of tons of rock and debris in response to the forces of gravity and dissipation. Their unpredictability and frequent location in remote areas have made observations of their dynamics rare. Through real-time detection and inverse modeling of teleseismic data, we show that landslide dynamics are primarily determined by the length scale of the source mass. When combined with geometric constraints from satellite imagery, the seismically determined landslide force histories yield estimates of landslide duration, momenta, potential energy loss, mass, and runout trajectory. Measurements of these dynamical properties for 29 teleseismogenic landslides are consistent with a simple acceleration model in which height drop and rupture depth scale with the length of the failing slope.

Geographic relations of landslide distribution and assessment of landslide hazards in the Blanco, Cibuco, and Coamo basins, Puerto Rico

USGS Publications Warehouse

Larsen, M.C.; Torres-Sanchez, A. J.

1996-01-01

Landslide occurrence is common in mountainous areas of Puerto Rico where mean annual rainfall and the frequency of intense storms are high and hillslopes are steep. Each year, landslides cause extensive damage to property and occasionally result in loss of life. Landslide maps developed from 1:20,000 scale aerial photographs in combination with a computerized geographic information system were used to evaluate the landslide potential in the Blanco, Cibuco, and Coamo Basins of Puerto Rico. These basins, ranging in surface area from 276 to 350 square kilometers, are described in this report. The basins represent a broad range of the climatologic, geographic, and geologic conditions that occur in Puerto Rico. In addition, a variety of landslide types were documented. Rainfall-triggered debris flows, shallow soil slips, and slumps were most abundant. The most important temporal control on landslide occurrence in Puerto Rico is storm rainfall. Forty-one storms triggered widespread landsliding about 1 to 2 times per year during the last three decades. These storms were frequently of 1 to 2 days duration in which, on average, several hundred millimeters of rainfall triggered tens to hundreds of landslides in the central mountains. Most of these storms were tropical disturbances that occurred during the hurricane season of June through November. Land use and the topographic characteristics of hillslope angle, elevation, and aspect are the most important spatial controls governing landslide frequency. Hillslopes in the study area that have been anthropogenically modified, exceed 12 degrees in gradient and about 350 meters in elevation, and face the east-northeast are most prone to landsliding. Bedrock geology and soil order seem less important in the determination of landslide frequency, at least when considered at a generalized level. A rainfall accumulation-duration relation for the triggering of numerous landslides throughout the central mountains, and a set of

1. GORGE HIGH DAM. THIS THIN ARCH DAM WITH A ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. GORGE HIGH DAM. THIS THIN ARCH DAM WITH A GRAVITY SECTION IS THE THIRD DAM BUILT BY SEATTLE CITY LIGHT TO PROVIDE WATER FOR GORGE POWERHOUSE AND WAS COMPLETED IN 1961, 1989. - Skagit Power Development, Gorge High Dam, On Skagit River, 2.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

Geologic characteristics and movement of the Meadow Creek landslide, part of the Coal Hill landslide complex, western Kane County, Utah

USGS Publications Warehouse

Ashland, Francis X.; McDonald, Greg N.; Carney, Stephanie M.; Tabet, David E.; Johnson, Cari L.

2010-01-01

The Meadow Creek landslide, part of the Coal Hill landslide complex in western Kane County, Utah, is about 1.7 miles (2.7 km) wide and 1.3 miles (2.1 km) long and contains six smaller historical slides. The upper part of the Meadow Creek landslide is gently sloping and consists of displaced and back-rotated blocks of Cretaceous Dakota and Cedar Mountain Formations that form northeast- to locally east-trending ridges that are separated by sediment-filled half-grabens. The lower part of the landslide is gently to moderately sloping, locally incised, and consists of heterogeneous debris that overrides the Jurassic Carmel Formation near Meadow Creek. Monitoring using a survey-grade Global Positioning System (GPS) instrument detected movement of the southern part of the Meadow Creek landslide between October 2005 and October 2008, including movement of two of the historical slides-landslides 1 and 2. The most movement during the measurement period occurred within the limits of persistently moving landslide 1 and ranged from about 24 to 64 inches (61-163 cm). Movement of the abutting southern part of the Meadow Creek landslide ranged from approximately 6 to 10 inches (15-25 cm). State Route 9 crosses over approximately a mile (1.6 km) of the southern part of the Meadow Creek landslide, including landslide 1. The highway and its predecessor (State Route 15) have been periodically displaced and damaged by persistent movement of landslide 1. Most of the landslide characteristics, particularly its size, probable depth, and the inferred weak strength and low permeability of clay-rich gouge derived from the Dakota and Cedar Mountain Formations, are adverse to and pose significant challenges to landslide stabilization. Secondary hazards include piping-induced sinkholes along scarps and ground cracks, and debris flows and rock falls from the main-scarp escarpment.

The 22 March 2014 Oso landslide, Washington, USA

NASA Astrophysics Data System (ADS)

Wartman, Joseph; Montgomery, David R.; Anderson, Scott A.; Keaton, Jeffrey R.; Benoît, Jean; dela Chapelle, John; Gilbert, Robert

2016-01-01

The Oso, Washington, USA, landslide occurred on the morning of Saturday, 22 March 2014 and claimed the lives of 43 people. The landslide began within an 200-m-high hillslope comprised of unconsolidated glacial and previous landslide/colluvial deposits; it continued as a debris avalanche/debris flow that rapidly inundated a neighborhood of 35 single-family residences. An intense three-week rainfall that immediately preceded the event most likely played a role in triggering the landslide; and other factors that likely contributed to destabilization of the landslide mass include alteration of the local groundwater recharge and hydrogeological regime from previous landsliding, weakening and alteration of the landslide mass caused by previous landsliding, and changes in stress distribution resulting from removal and deposition of material from earlier landsliding. Field reconnaissance following the event revealed six distinctive zones and several subzones that are characterized on the basis of geomorphic expression, styles of deformation, geologic materials, and the types, size, and orientation of vegetation. Seismic recording of the landslide indicate that the event was marked by several vibration-generating episodes of mass movement. We hypothesize that the landslide occurred in two stages, with the first being a sequential remobilization of existing slide masses from the most recent (2006) landslide and from an ancient slide that triggered a devastating debris avalanche/debris flow. The second stage involved headward extension into previously unfailed material that occurred in response to unloading and redirection of stresses.

Into the complexity of coseismic landslide clustering

NASA Astrophysics Data System (ADS)

Meunier, Patrick; Marc, Odin; Uchida, Taro; Hovius, Niels

2014-05-01

Earthquake-triggered landslides tend to cluster along topographic crests while rainfall-induced landslides are more uniformly distributed on hillslopes [1]. In theory, rainfall induced landslides should even occur downslope preferentially, where pore pressure induced by groundwater flows is the highest. Past studies on landslide clustering are all based on the analysis of complete dataset or subdataset of landslides associated with a given event (seismic or climatic) as a whole. In this work, we document the spatial variation of the landslide position (on hillslopes) within the epicentral area for the cases of the 1999 Chichi, the 2004 Niigata and the 2008 Iwate earthquakes. We show that landslide clustering is not uniform in space and exhibit patterns that vary a lot from one case to another. These patterns are not easy to interpret as they don't seem to be controlled by a single governing parameter but result from a complex interaction between local (hillslope length and gradient, lithology) and seismic (distance to source, slope aspect, radiation pattern, coseismic uplift) parameters. [1] Meunier, P., Hovius, N., & Haines, J. A. (2008). Topographic site effects and the location of earthquake induced landslides. Earth and Planetary Science Letters, 275(3), 221-232.

A suggested method for reporting a landslide

USGS Publications Warehouse

Fell, Robin; Lacerda, W.; Cruden, D.M.; Evans, S.G.; LaRochelle, P.; Martinez, Fernando; Beltran, Lisandro; Jesenak, J.; Novograd, S.; Krauter, E.; Slunga, E.; Pilot, G.A.; Brand, E.W.; Farkas, J.; Bhandari, R.K.; Cotecchia, V.; Esu, Franco; Fujita, H.; Nakamura, H.; Sassa, K.; Ting, W.H.; Salt, Graham; Janbu, Nilmar; Nespak, A.M.; Gongxian, Wang; Zhuoyuan , Zhang; Michelena, R.; Popescu, Mihai; Viberg, Leif; Bonnard, C.; Hutchinson, J.N.; Einstein , H.H.; Schuster, R.L.; Varnes, D.J.; Ter-Martiros­ian, Z.G.; Ter-Stepanian, G.I.; Anagnosti, P.; Hashizume, M.; Watanabe, Masayuki

1990-01-01

The Landslide Report is a Suggested Method developed by the International Geotechnical Societies' UNESCO Working Party on World Landslide Inventory for reporting the position, date, type, geometry, volume and damage of significant landslides.

Probabilistic landslide susceptibility mapping in the Lai Chau province of Vietnam: focus on the relationship between tectonic fractures and landslides

NASA Astrophysics Data System (ADS)

Lee, Saro; Dan, Nguyen Tu

2005-09-01

This study evaluates the susceptibility of landslides in the Lai Chau province of Vietnam using Geographic Information System (GIS) and remote sensing data to focus on the relationship between tectonic fractures and landslides. Landslide locations were identified from aerial photographs and field surveys. Topographic, geological data and satellite images were collected, processed, and constructed into a spatial database using GIS data and image-processing techniques. A scheme of the tectonic fracturing of crust in the Lai Chau region was established. Lai Chau was identified as a region with many crustal fractures, where the grade of tectonic fracture is closely related to landslide occurrence. The influencing factors of landslide occurrence were: distance from a tectonic fracture, slope, aspect, curvature, soil, and vegetative land cover. Landslide prone areas were analyzed and mapped using the landslide occurrence factors employing the probability-frequency ratio model. The results of the analysis were verified using landslide location data and showed 83.47% prediction accuracy. That emphasized a strong relationship between the susceptibility map and the existing landslide location data. The results of this study can form a basis stable development and land use planning for the region.

Deer Creek Dam, Dam, 1,204 feet/238 degrees from intersection of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Deer Creek Dam, Dam, 1,204 feet/238 degrees from intersection of dam complex access road and U.S. Highway 189 to center of dam, 874 feet/352 degrees from Hydroelectric Powerplant (HAER UT-93-B) to center of dam, Charleston, Wasatch County, UT

McNary Dam, Ice Harbor Dam, and Lower Monumental Dam Smolt Monitoring Program; 1996 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hillson, Todd; Lind, Sharon; Price, William

1997-07-01

The Washington Department of Fish & Wildlife (WDFW) assumed responsibility for the Smolt Monitoring Program at McNary Dam on the Columbia River in 1990 and at the new juvenile collection facility at Lower Monumental Dam on the Snake River in 1993. In 1996, Smolt Monitoring Program activities also began at the new juvenile collection facility located at Ice Harbor Dam. This report summarizes the 1996 Smolt Monitoring work at all three sites. The work at Ice Harbor consisted of Gas Bubble Trauma (GBT) monitoring only. In general, the 1996 passage season at both the McNary and Lower Monumental sites canmore » be characterized by reduced passage of juveniles through the collection systems due to elevated river flows and spill, and low (<1%) overall facility mortality rates most likely resulting from cooler water temperatures. In accordance with the National Marine Fisheries Service recommendations (NMFS, 1995) all spring migrants were bypassed at McNary Dam in 1996. Mechanical problems within the McNary collection system resulted in collection and sampling activities being delayed until April 18 at this site, while sampling and collection began on the scheduled starting date of April 1 at Lower Monumental Dam. Monitoring operations were conducted through December 14 at McNary Dam and through October 28 at Lower Monumental Dam. An ongoing transportation evaluation summer migrant marking program was conducted at McNary Dam in 1996 by the NMFS. This necessitated the sampling of 394,211 additional fish beyond the recommended sampling guidelines. All total, 509,237 and 31,219 juvenile salmonids were anesthetized and individually counted, examined for scale loss, injuries, and brands by WDFW Smolt Monitoring personnel in 1996 at McNary Dam and Lower Monumental Dam, respectively.« less

Anaglyph, Lake Palanskoye Landslide, Kamchatka Peninsula, Russia

NASA Technical Reports Server (NTRS)

2000-01-01

The Lake Palanskoye in northern Kamchatka was formed when a large landslide disrupted the drainage pattern, forming a natural dam. The area is volcanically and tectonically active and it is likely that the landslide -- which covers about 80 square kilometers (30 square miles) --was triggered by an earthquake sometime in the past 10,000 years. The source area of the landslide is the ridge to the upper left of the lake. The steep topographic scar at the head of the slide and the broad expanse of hummocky landslide debris that covers the valley to the left of the lake are visible in 3D.

This anaglyph was generated by first draping a Landsat Thematic Mapper near-infrared image over a topographic map from the Shuttle Radar Topography Mission, then using the topographic data to create two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.

Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30 meter (99 foot) spatial resolution of most Landsat images and will provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, South Dakota.

The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface on its 11-day mission. To collect the 3-D data, engineers added a 60-meter

New classification of landslide-inducing anthropogenic activities

NASA Astrophysics Data System (ADS)

Michoud, C.; Jaboyedoff, M.; Derron, M.-H.; Nadim, F.; Leroi, E.

2012-04-01

Although landslides are usually considered typical examples of natural hazards, they can be influenced by human activities. Many examples can be found in the literature about slope instabilities induced by anthropogenic activities, ranging from small superficial landslides to rock avalanches. Research on this topic is of primary importance for understanding and mitigation of landslide risk. Indeed, slope stabilities influenced by human actions contribute significantly to the risk level because, by definition, they are located where elements at risk and people are present. Within the framework of the European project SafeLand "Living with Landslide Risk in Europe", the authors analyzed the landslides induced by anthropogenic factors in Europe and elsewhere (SafeLand deliverable D1.6). During the bibliographical research, it appeared that a complete and illustrated classification on human activities influencing slope stabilities does not yet exist. Therefore, a new classification was introduced by Michoud et al. (2011) about anthropogenic activities affecting slope stability conditions. This classification takes into account conceptual processes leading to landslides (Terzaghi, 1950; Jaboyedoff and Derron, 2005) and the distinction between destabilization factors and triggering factors (Vaunat et al., 1994; Leroueil et al., 1996). The classification was tested and improved through fifty-eight well-documented case studies, even lots of large landslides, such as Elm, Aberfan, Namsos and Rissa landslides, etc. Furthermore, the boundary between natural and "anthropogenic" landslide triggers (e.g. water run-off modified by new land-uses, creating landslides some km farther), and the time during which changes and reactions are to be considered as direct consequences of human activities were highlighted. Finally, anthropogenic influences can also be positive and examples of (non-voluntary) positive human impacts on slope stability are presented. Jaboyedoff, M. and Derron, M

Monsoon Rainfall and Landslides in Nepal

NASA Astrophysics Data System (ADS)

Dahal, R. K.; Hasegawa, S.; Bhandary, N. P.; Yatabe, R.

2009-12-01

A large number of human settlements on the Nepal Himalayas are situated either on old landslide mass or on landslide-prone areas. As a result, a great number of people are affected by large- and small-scale landslides all over the Himalayas especially during monsoon periods. In Nepal, only in the half monsoon period (June 10 to August 15), 70, 50 and 68 people were killed from landslides in 2007, 2008 and 2009, respectively. In this context, this paper highlights monsoon rainfall and their implications in the Nepal Himalaya. In Nepal, monsoon is major source of rainfall in summer and approximately 80% of the annual total rainfall occurs from June to September. The measured values of mean annual precipitation in Nepal range from a low of approximately 250 mm at area north of the Himalaya to many areas exceeding 6,000 mm. The mean annual rainfall varying between 1500 mm and 2500 mm predominate over most of the country. In Nepal, the daily distribution of precipitation during rainy season is also uneven. Sometime 10% of the total annual precipitation can occur in a single day. Similarly, 50% total annual rainfall also can occur within 10 days of monsoon. This type of uneven distribution plays an important role in triggering many landslides in Nepal. When spatial distribution of landslides was evaluated from record of more than 650 landslides, it is found that more landslides events were concentrated at central Nepal in the area of high mean annual rainfall. When monsoon rainfall and landslide relationship was taken into consideration, it was noticed that a considerable number of landslides were triggered in the Himalaya by continuous rainfall of 3 to 90 days. It has been noticed that continuous rainfall of few days (5 days or 7 days or 10 days) are usually responsible for landsliding in the Nepal Himalaya. Monsoon rains usually fall with interruptions of 2-3 days and are generally characterized by low intensity and long duration. Thus, there is a strong role of

Reprint of "A proposed cell model for multiple-occurrence regional landslide events: Implications for landslide susceptibility mapping"

NASA Astrophysics Data System (ADS)

Crozier, M. J.

2018-04-01

Multiple-occurrence regional landslide events (MORLEs) consist of hundreds to thousands of shallow landslides occurring more or less simultaneously within defined areas, ranging from tens to thousands of square kilometres. While MORLEs can be triggered by rainstorms and earthquakes, this paper is confined to those landslide events triggered by rainstorms. Globally, MORLEs occur in a range of geological settings in areas of moderate to steep slopes subject to intense rainstorms. Individual landslides in rainstorm-triggered events are dominantly small, shallow debris and earth flows, and debris and earth slides involving regolith or weathered bedrock. The model used to characterise these events assumes that energy distribution within the event area is represented on the land surface by a cell structure; with maximum energy expenditure within an identifiable core and rapid dissipation concentrically away from the centre. The version of the model presented here has been developed for rainfall-triggered landslide events. It proposes that rainfall intensity can be used to determine different critical landslide response zones within the cell (referred to as core, middle, and periphery zones). These zones are most readily distinguished by two conditions: the proportion of the slope that fails and the particular type of the slope stability factor that assumes dominance in determining specific sites of landslide occurrence. The latter condition means that the power of any slope stability factor to distinguish between stable and unstable sites varies throughout the affected area in accordance with the landslide response zones within the cell; certain factors critical for determining the location of landslide sites in one part of the event area have little influence in other parts of the event area. The implication is that landslide susceptibility maps (and subsequently derived mitigation measures) based on conventional slope stability factors may have only limited validity

The Hungtsaiping landslide:A kinematic model based on morphology

NASA Astrophysics Data System (ADS)

Huang, W.-K.; Chu, H.-K.; Lo, C.-M.; Lin, M.-L.

2012-04-01

A large and deep-seated landslide at Hungtsaiping was triggered by the 7.3 magnitude 1999 Chi-Chi earthquake. Extensive site investigations of the landslide were conducted including field reconnaissance, geophysical exploration, borehole logs, and laboratory experiments. Thick colluvium was found around the landslide area and indicated the occurrence of a large ancient landslide. This study presents the catastrophic landslide event which occurred during the Chi-Chi earthquake. The mechanism of the 1999 landslide which cannot be revealed by the underground exploration data alone, is clarified. This research include investigations of the landslide kinematic process and the deposition geometry. A 3D discrete element method (program), PFC3D, was used to model the kinematic process that led to the landslide. The proposed procedure enables a rational and efficient way to simulate the landslide dynamic process. Key word: Hungtsaiping catastrophic landslide, kinematic process, deposition geometry, discrete element method

Multiple flow processes accompanying a dam-break flood in a small upland watershed, Centralia, Washington

USGS Publications Warehouse

Costa, John E.

1994-01-01

On October 5, 1991, following 35 consecutive days of dry weather, a 105-meter long, 37-meter wide, 5.2-meter deep concrete-lined watersupply reservoir on a hillside in the eastern edge of Centralia, Washington, suddenly failed, sending 13,250 cubic meters of water rushing down a small, steep tributary channel into the city. Two houses were destroyed, several others damaged, mud and debris were deposited in streets, on lawns, and in basements over four city blocks, and 400 people were evacuated. The cause of failure is believed to have been a sliding failure along a weak seam or joint in the siltstone bedrock beneath the reservoir, possibly triggered by increased seepage into the rock foundation through continued deterioration of concrete panel seams, and a slight rise (0.6 meters) in the pool elevation. A second adjacent reservoir containing 18,900 cubic meters of water also drained, but far more slowly, when a 41-cm diameter connecting pipe was broken by the landslide. The maximum discharge resulting from the dam-failure was about 71 cubic meters per second. A reconstructed hydrograph based on the known reservoir volume and calculated peak discharge indicates the flood duration was about 6.2 minutes. Sedimentologic evidence, high-water mark distribution, and landforms preserved in the valley floor indicate that the dam failure flood consisted of two flow phases: an initial debris flow that deposited coarse bouldery sediment along the slope-area reach as it lost volume, followed soon after by a water-flood that achieved a stage about one-half meter higher than the debris flow. The Centralia dam failure is one of three constructed dams destroyed by rapid foundation failure that defines the upper limits of an envelope curve of peak flood discharge as a function of potential energy for failed constructed dams worldwide.

Landslide Hazards

USGS Publications Warehouse

,

2000-01-01

Landslide hazards occur in many places around What Can You Do If You Live Near Steep Hills? the world and include fast-moving debris flows, slow-moving landslides, and a variety of flows and slides initiating from volcanoes. Each year, these hazards cost billions of dollars and cause numerous fatalities and injuries. Awareness and education about these hazards is a first step toward reducing damaging effects. The U.S. Geological Survey conducts research and distributes information about geologic hazards. This Fact Sheet is published in English and Spanish and can be reproduced in any form for further distribution. 

Landslides on Charon

NASA Image and Video Library

2016-10-18

Scientists from NASA's New Horizons mission have spotted signs of long run-out landslides on Pluto's largest moon, Charon. This image of Charon's informally named "Serenity Chasma" was taken by New Horizons' Long Range Reconnaissance Imager (LORRI) on July 14, 2015, from a distance of 48,912 miles (78,717 kilometers). An annotated image shows arrows in the annotated figure mark indications of landslide activity at http://photojournal.jpl.nasa.gov/catalog/PIA21128

Directions of the US Geological Survey Landslide Hazards Reduction Program

USGS Publications Warehouse

Wieczorek, G.F.

1993-01-01

The US Geological Survey (USGS) Landslide Hazards Reduction Program includes studies of landslide process and prediction, landslide susceptibility and risk mapping, landslide recurrence and slope evolution, and research application and technology transfer. Studies of landslide processes have been recently conducted in Virginia, Utah, California, Alaska, and Hawaii, Landslide susceptibility maps provide a very important tool for landslide hazard reduction. The effects of engineering-geologic characteristics of rocks, seismic activity, short and long-term climatic change on landslide recurrence are under study. Detailed measurement of movement and deformation has begun on some active landslides. -from Author

Giant landslide deposits and the modalities of their removal by fluvial sediment export in the central Himalayas

NASA Astrophysics Data System (ADS)

Lave, Jerome; Lénard, Sébastien; Lanord, Christian France

2017-04-01

Slope failures and deep seated landslides are usually considered as the most efficient processes for hillslope erosion in active orogens. Erosion in the Narayani basin in central Himalaya (Nepal) confirms such assertion, with in addition the probable predominance of the very large landslides in the erosive budget of the range. In the High Himalayan part of this basin, a number of pluri-kilometric giant landslides have been described and involve up to ten cubic kilometres mass wasting (e.g. Weidinger et al., 2002). In this contribution, we discuss how the fluvial network do respond to such massive and sudden supply of debris, basing our analysis on several cases, documented by sedimentologic and geomorphologic observations, lithologic counting, geochemical tracing (down to the Ganga plain), and 14C or CRN dating. We first demonstrate that several massive fill terraces preserved along the Lesser Himalayan intramontane reaches are not climatically induced, but rather represent transient storage following giant landslide material export. Two types of deposits and therefore of sediment export modalities have been identified: either (1), as observed along a 100km long stretch of the Marsyandi river, through massive debris flow(s) runout following the break of a landslide-induced dam on main rivers, or (2) by the more gradual but efficient fluvial removal of the giant landslide deposits. In the second case, in particular when bedrock fracturing and crushing during landslide fall has strongly reduced the average debris size, because the steep Himalayan rivers are usually in strong over capacity or largely underloaded with fine to medium-size sediment, their can carry up to several cubic kilometres of sediments in one or two centuries. The coarsest part of the exported material is temporarily stored through aggradation in the massive Lesser Himalayan fill terraces because river gradient drops suddenly when river exits the High Himalaya, whereas the finest fraction is

Estimating the empirical probability of submarine landslide occurrence

USGS Publications Warehouse

Geist, Eric L.; Parsons, Thomas E.; Mosher, David C.; Shipp, Craig; Moscardelli, Lorena; Chaytor, Jason D.; Baxter, Christopher D. P.; Lee, Homa J.; Urgeles, Roger

2010-01-01

The empirical probability for the occurrence of submarine landslides at a given location can be estimated from age dates of past landslides. In this study, tools developed to estimate earthquake probability from paleoseismic horizons are adapted to estimate submarine landslide probability. In both types of estimates, one has to account for the uncertainty associated with age-dating individual events as well as the open time intervals before and after the observed sequence of landslides. For observed sequences of submarine landslides, we typically only have the age date of the youngest event and possibly of a seismic horizon that lies below the oldest event in a landslide sequence. We use an empirical Bayes analysis based on the Poisson-Gamma conjugate prior model specifically applied to the landslide probability problem. This model assumes that landslide events as imaged in geophysical data are independent and occur in time according to a Poisson distribution characterized by a rate parameter λ. With this method, we are able to estimate the most likely value of λ and, importantly, the range of uncertainty in this estimate. Examples considered include landslide sequences observed in the Santa Barbara Channel, California, and in Port Valdez, Alaska. We confirm that given the uncertainties of age dating that landslide complexes can be treated as single events by performing statistical test of age dates representing the main failure episode of the Holocene Storegga landslide complex.

Self-Potential Monitoring of Landslides on Field and Laboratory Scale

NASA Astrophysics Data System (ADS)

Heinze, T.; Limbrock, J. K.; Weigand, M.; Wagner, F. M.; Kemna, A.

2017-12-01

Among several other geophysical methods used to observe water movement in the ground, the electrical self-potential method has been applied to a broad range of monitoring studies, especially focusing on volcanism and dam leakage but also during hydraulic fracturing. Electrical self-potential signals may be caused by various mechanisms. Though, the most relevant source of the self-potential field in the given context of landslides is the streaming potential, caused by a flowing electrolyte through porous media with electrically charged internal surfaces. So far, existing models focus on monitoring water flow in non-deformable porous media. However, as the self-potential is sensitive to hydraulic parameters of the soil, any change in these parameters will cause an alteration of the electric signal. Mass movement will significantly influence the hydraulic parameters of the solid as well as the pressure field, assuming that fluid movement is faster than pressure diffusion. We present self-potential measurements from over a year of continuous monitoring at an old landslide site. Using a three-dimensional electric-resistivity underground model, the self-potential signal is analyzed with respect to precipitation and the resulting flow in the ground. Additional data from electrical measurements and conventional sensors are included to assess saturation. The field observations are supplemented by laboratory experiments in which we study the behavior of the self-potential during failure of a piled land slope. For the undrained scenarios, we observe a clear correlation between the mass movements and signals in the electric potential, which clearly differ from the underlying potential variations due to increased saturation and fluid flow. In the drained experiments, we do not observe any measurable change in the electric potential. We therefore assume that change in fluid properties and release of the load causes disturbances in flow and streaming potential. Our results

Integration and comparison of different acquisition techniques for landslide monitoring: Cancia landslide case study

NASA Astrophysics Data System (ADS)

Masiero, Andrea; Fissore, Francesca; Degetto, Massimo; Piermattei, Livia; Guarnieri, Alberto; Mezzomo, Rizieri; Gregoretti, Carlo; Piragnolo, Marco; Pirotti, Francesco; Vettore, Antonio

2017-04-01

Terrain instability, landslides and other phenomena mostly caused by hydrogeological risk, often cause damages to human infrastructures, roads and other transport lines: given the recent developments in surveying, electronics and mobile instrumentation, the quest for automated or semi-automated early warning systems is continuously increasing in order to provide reliable technological solutions to reduce risks for both human lives and human building and infrastructures. This work deals with the monitoring a specific area of interest, a landslide located in Cancia (Belluno, Italy). This case study is characterized by the presence of several roads close to the landslide area: in particular, one of them intersects with the landslide. The closeness between landslide and human used areas (e.g. roads) motivate the interest of public authorities in order to reduce risks related to the landslide. To this aim, "Provincia di Belluno, Servizio Difesa del Suolo" actively contributed to this work by providing aerial imagery data of the region of interest. Accessing a reliable reconstruction of certain landslides can be complex due to the difficulty for humans to reach certain areas: often only part of the area of interest can be acquired with highly accurate ground surveying (e.g. terrestrial laser scanning (TLS)), whereas other methods should be considered in order to obtain estimates of the remaining parts of the landslide. Recently, the spread of low cost drones is leading to a growing interest in the choice of unmanned aerial vehicles (UAVs) to acquire aerial imagery, hence enabling low cost photogrammetric reconstruction of the area. Despite being an attractive solution because of the clear convenience in terms of cost and acquisition time, its accuracy has typically not reached that of TLS surveying so far. This paper considers the possibility of comparing and integrating different acquisition techniques (TLS, aerial and close-range photogrammetry) in order to reach the

Monitoring landslide dynamics using timeseries of UAV imagery

NASA Astrophysics Data System (ADS)

de Jong, S. M.; Van Beek, L. P.

2017-12-01

Landslides are worldwide occurring processes that can have large economic impact and sometimes result in fatalities. Multiple factors are important in landslide processes and can make an area prone to landslide activity. Human factors like drainage and removal of vegetation or land clearing are examples of factors that may cause a landslide. Other environmental factors such as topography and the shear strength of the slope material are more difficult to control. Triggering factors for landslides are typically heavy rainfall events or sometimes by earthquakes or under cutting processes by a river. The collection of data about existing landslides in a given area is important for predicting future landslides in that region. We have setup a monitoring program for landslide using cameras aboard Unmanned Airborne Vehicles. UAV with cameras are able to collect ultra-high resolution images and UAVs can be operated in a very flexible way, they just fit in the back of a car. Here, in this study we used Unmanned Aerial Vehicles to collect a time series of high-resolution images over landslides in France and Australia. The algorithm used to process the UAV images into OrthoMosaics and OrthoDEMs is Structure from Motion (SfM). The process generally results in centimeter precision in the horizontal and vertical direction. Such multi-temporal datasets enable the detection of landslide area, the leading edge slope, temporal patterns and volumetric changes of particular areas of the landslide. We measured and computed surface movement of the landslide using the COSI-Corr image correlation algorithm with ground validation. Our study shows the possibilities of generating accurate Digital Surface Models (DSMs) of landslides using images collected with an Unmanned Aerial Vehicle (UAV). The technique is robust and repeatable such that a substantial time series of datasets can be routinely collected. It is shown that a time-series of UAV images can be used to map landslide movements with

Landslides in Flanders (Belgium): Where science meets public policy

NASA Astrophysics Data System (ADS)

van den Eeckhaut, M.; Poesen, J.; Vandekerckhove, L.

2009-04-01

Although scientific research on landslides in the Flemish Ardennes (710 km²; Belgium), has been conducted over the last decades, the Flemish Government only took account of slope failure as a soil degradation process after the occurrence of several damaging landslides in the beginning of the 21st century. Here we aim to present the successful collaboration between the Physical and Regional Geography Research Group (FRG; Dept. Earth and Environmental Sciences K.U.Leuven) and the Environment, Nature and Energy Department (LNE; Flemish Government) in landslide management. We will demonstrate how geomorphologists produced practical tools for landslide management which can be directly applied by LNE as well as other local and regional authorities and planners. Since 2004 three projects on landslide inventory mapping and susceptibility assessment in the Flemish Ardennes have been funded by LNE, and a fourth one on landslide susceptibility assessment in remaining hilly regions in Flanders west of Brussels recently started. Together with a steering committee composed of stakeholders, persons from LNE supervise the research carried out by geomorphologists experienced in landslide studies. For the establishment of the landslide inventory map of the Flemish Ardennes we combined the analysis of LIDAR-derived hillshade and contour line maps with detailed field controls. Additional information was collected through interviews with local authorities and inhabitants and from analysis of newspaper articles and technical reports. Then, a statistical model, logistic regression, was applied to produce a high quality classified landslide susceptibility map. The unique part of this collaboration is that all end products are online available at user-friendly websites designed by LNE. The scientific report containing (1) general information on landslides, (2) a description of the study area, (3) an explanation of the materials and methods used, (4) a presentation of the resulting

UAV-based landslide deformation monitoring - first results from Corvara landslide

NASA Astrophysics Data System (ADS)

Thiebes, Benni; Tomelleri, Enrico; Mejia-Aguilar, Abraham; Schlögel, Romy; Darvishi, Mehdi; Remondino, Fabio; Toschi, Isabella; Rutzinger, Martin; Zieher, Thomas

2016-04-01

In recent years, unmanned aerial vehicles (UAVs) have been more frequently utilised to study geomorphological and natural hazard processes, including gravitational mass movements such as landslides. UAVs can be equipped with different sensors, e.g. photo cameras and laser scanners, and the data that can be achieved can substantially improve the monitoring and understanding of the involved natural processes. One of the main advantages of UAVs is their flexibility that allows for carrying out assessments of large areas in short periods of time and at much lower costs than other platforms, e.g. airplanes or helicopters. Thereby, UAVs represent an interesting technique to complement more traditional monitoring methods. Here we present some first results of the EUREGIO-funded LEMONADE project that is concerned with the combination and integration of novel and traditional landslide monitoring techniques. We carried out a series of UAV flights over a particularly active part of the Corvara landslide and acquired aerial imagery for quantitative assessments of the retrogressive enlargement of the landslide over recent years. Additional field surveys including terrestrial laser scanning, and UAV-based photogrammetry and laser scanning are scheduled for summer 2016. The Corvara landslide is a large complex earthflow in the Italian Dolomites that has been investigated by a wide range of methodologies over the past years. The landslide is characterised by movement patterns of greatly varying magnitude, ranging from annual rates of a few cm to more than 20 m. The current and past monitoring activities concentrated on GPS measurements as well as multi-temporal differential radar interferometry utilising artificial corner reflectors. Thereby, primarily punctual displacement data were achieved and spatial information on topographic and geomorphic changes were consequently sparse. For our photogrammetry study, we utilised a SoLeon octocopter equipped with a Ricoh GR 16.2 Megapixels

Small scale karst features (tube karren) as evidence of a latest Quaternary fossil landslide

NASA Astrophysics Data System (ADS)

Stöger, Tobias; Plan, Lukas; Draganits, Erich

2017-04-01

At least since 1933 numerous small dissolutional holes in the ceilings of overhangs and small caves have been known from a restricted area in the Northern Calcareous Alps in Lower Austria but not investigated yet. These tube-shaped structures are a few centimetres in diameter, more or less vertical, taper upwards, are closed at the top and penetrate some tens of centimetres into the Middle Triassic limestone. Very similar features were described by Simms (2002) from the shores of three lakes in western Ireland and termed Röhrenkarren or tube karren. According to his model they formed by condensation corrosion within air pockets trapped by seasonal floods. The features investigated in the present study occur on both sides of a valley in the north eastern part of the Northern Calcareous Alps south of the city Sankt Pölten. Presently there is no lake and so far no paleo lake is known from this area. Based on airborne laser scanning data and field observations in a narrow section of the valley downstream of the tube karren sites, a previously unknown potential fossil landslide was discovered. The clayey silty sediments upstream of the landslide are interpreted as palaeo-lake sediments. This interpretation is supported by the existence of abundant dragonfly eggs within these deposits. The same fine-grained sediments are partly also found inside the tube karren. These observations are interpreted that a landslide-dammed palaeo-lake formed due to the mass movement that blocked the river and the tube karren were formed by seasonal fluctuations of the lake level. Geochronological dating of calcite crusts covering the karren and of the organic material of the dragonfly eggs are on the way. As the karren features look quite fresh and unweathered and from the diffuse shape of the landslide a late Quaternary age is estimated. References Simms, M.J. 2002. The origin of enigmatic, tubular, lake-shore karren: a mechanism for rapid dissolution of limestone in carbonate

The inner structure of landslides and landslide-prone slopes in south German cuesta landscapes assessed by geophysical, geomorphological and sedimentological approaches

NASA Astrophysics Data System (ADS)

Schwindt, Daniel; Sandmeier, Christine; Büdel, Christian; Jäger, Daniel; Wilde, Martina; Terhorst, Birgit

2016-04-01

Investigations on landslide activity in the cuesta landscape of Germany, usually characterized by an interbedding of morphologically hard (e.g. sand-/limestones) and soft (clay) sedimentary rocks are relatively sparse. However, spring 2013 has once again revealed a high susceptibility of the slopes in the Franconian and Swabian Alb to mass movements, when enduring rainfalls initiated numerous landslides causing considerable damage to settlements and infrastructure. Many aspects like the spatial distribution of landslides, triggering factors, and process dynamics - especially with view on the reactivation of landslides - require intensive investigations to allow for assessment of the landslide vulnerability and the development of reliable early-warning systems. Aim of the study is to achieve a deeper insight into the triggering factors and the process dynamics of landslides in the cuesta landscape with special regard on landslide proneness of slopes and the potential reactivation of old landslides. A multi-methodological approach was conducted based on geophysical investigations (seismic refraction tomography - SRT, electrical resistivity tomography - ERT), geomorphological mapping, morphometric GIS-based analysis, core soundings and substrate mapping. Study sites are located in the Swabian Alb (southwestern Germany) in the Jurassic escarpment where where Oxfordian marls and limestones superimpose Callovian clays, as well as in the northeastern Franconian Alb, within the escarpment of the so called Rhätolias with with red claystones of the late Norian (Feuerletten formation) below interbedding layers of sand- and claystones of the Rhaetian (Upper Triassic) and Hettangian ( Lower Jurassic). The investigated landslides strongly differ with respect to their age, from young landslides originated in spring 2013 to ancient landslides. Investigations reveal a distinct diversity of landslide types composed of a complex combination of processes. The applied methods allow

ECHETA DAM SPILLWAY. COMING OUT BELOW THE DAM. AT CENTER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ECHETA DAM SPILLWAY. COMING OUT BELOW THE DAM. AT CENTER OF PHOTO. VIEW TO NORTHEAST. - Echeta Dam & Reservoir, 2.9 miles east of Echeta Road at Echeta Railroad Siding at County Road 293, Echeta, Campbell County, WY

Landslide in Coprates

NASA Technical Reports Server (NTRS)

2004-01-01

15 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the distal (far) end of a landslide deposit in Coprates Chasma, part of the vast Valles Marineris trough system. Large boulders, the size of buildings, occur on the landslide surface. This October 2004 picture is located near 15.3oS, 54.6oW, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left.

Building rainfall thresholds for large-scales landslides by extracting occurrence time of landslides from seismic records

NASA Astrophysics Data System (ADS)

Yen, Hsin-Yi; Lin, Guan-Wei

2017-04-01

Understanding the rainfall condition which triggers mass moment on hillslope is the key to forecast rainfall-induced slope hazards, and the exact time of landslide occurrence is one of the basic information for rainfall statistics. In the study, we focused on large-scale landslides (LSLs) with disturbed area larger than 10 ha and conducted a string of studies including the recognition of landslide-induced ground motions and the analyses of different terms of rainfall thresholds. More than 10 heavy typhoons during the periods of 2005-2014 in Taiwan induced more than hundreds of LSLs and provided the opportunity to characterize the rainfall conditions which trigger LSLs. A total of 101 landslide-induced seismic signals were identified from the records of Taiwan seismic network. These signals exposed the occurrence time of landslide to assess rainfall conditions. Rainfall analyses showed that LSLs occurred when cumulative rainfall exceeded 500 mm. The results of rainfall-threshold analyses revealed that it is difficult to distinct LSLs from small-scale landslides (SSLs) by the I-D and R-D methods, but the I-R method can achieve the discrimination. Besides, an enhanced three-factor threshold considering deep water content was proposed as the rainfall threshold for LSLs.

ECHETA DAM RIPRAP ON RESERVOIR SIDE OF THE DAM AT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ECHETA DAM RIP-RAP ON RESERVOIR SIDE OF THE DAM AT BREACH. VIEW TO NORTH-NORTHEAST. - Echeta Dam & Reservoir, 2.9 miles east of Echeta Road at Echeta Railroad Siding at County Road 293, Echeta, Campbell County, WY

Small Landslides in Aram-Ares Channel, Mars

NASA Astrophysics Data System (ADS)

Kraal, E. R.; Shoup, J.

2014-12-01

An east-west channel (located at 341°E and 3°N) connects Aram Chaos to Ares Valles. The valley is approximately 80 km long, 12 km wide, and 1.5 km deep. The channel is filled with a series of slope failures or landslides that form lobate aprons covering the valley floor. Preliminary studies of the valley on the north wall of the valley (south facing) characterized 6 landslides using gridded MOLA topography from JMARS, including area, drop height and run out distance. These relatively small landslides have surface areas ranging from 5.6 to 55 km2. Their aprons run out ~ 10 km, often covering the entire width of the valley floor. Drop height was measured using both maximum and minimum estimates due to resolution limits of the topography and ranged from 1200 to 2200 meters. Using the drop height and run out distance, we determine the coefficient of friction and maximum velocity for two of the landslides using previously established landslide equations based on physical properties. The coefficient of friction for the landslide events ranged from 0.5 to 1.5, which corresponds to a maximum landslide velocity of 87 m/s2 to 96 m/s2. The variations in the coefficients may be due to landslides size, relative size, or possible volatile or ice content. Preliminary geomorphic surface mapping is currently under way to identify the relationship between the aprons and the channel floor, relative age of the landslides, and other characteristics. Initial analysis indicates the channel floor and depositional aprons have experienced deflation and eolian processes and aprons have a variable level of erosion indicating that the landslides did not form during a single event.

The Dams and Monitoring Systems and Case Study: Ataturk and Karakaya Dams

NASA Astrophysics Data System (ADS)

Kalkan, Y.; Bilgi, S.; Gülnerman, A. G.

2017-12-01

Dams are among the most important engineering structures used for flood controls, agricultural purposes as well as drinking and hydroelectric power. Especially after the Second World War, developments on the construction technology, increase the construction of larger capacity dams. There are more than 150.000 dams in the world and almost 1000 dams in Turkey, according to international criteria. Although dams provide benefits to humans, they possess structural risks too. To determine the performance of dams on structural safety, assessing the spatial data is very important. These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. These physical data are measured and monitored by the instruments and equipment. Dams and their surroundings have to be monitored by using essential methods at periodic time intervals in order to determine the possible changes that may occur over the time. Monitoring programs typically consist of; surveillance or visual observation. These programs on dams provide information for evaluating the dam's performance related to the design intent and expected changes that could affect the safety performance of the dam. Additionally, these programs are used for investigating and evaluating the abnormal or degrading performance where any remedial action is necessary. Geodetic and non-geodetic methods are used for monitoring. Monitoring the performance of the dams is critical for producing and maintaining the safe dams. This study provides some general information on dams and their different monitoring systems by taking into account two different dams and their structural specifications with the required information. The case study in this paper depends on a comparison of the monitoring surveys on Atatürk Dam and Karakaya Dam, which are constructed on Firat River with two different structural

The Gardiola landslide: evolution and reactivation threshold definition through eight years of continuous monitoring activity

NASA Astrophysics Data System (ADS)

Allasia, P.; Baldo, M.; Giordan, D.; Lollino, G.

2009-04-01

Following heavy rainfalls and due to the particular meteo-climatic conditions occurred on October 16th, 2000, the north western part of Italy was interested by widespread landslides and flood phenomena. In particular a landslide phenomenon was triggered along the left side of Val Germanasca that exposed the Provincial Road No. 169 to risk. The extent of the unstable volume (about 700,000 cubic meters) could have led, in case of failure, to a natural damming of the valley that could have been followed by a dam-break flood. Thus the urgent need to monitor the evolving phenomenon and to assess all the available actions to be taken in order to mitigate the risk. After the installation of a first provisional monitoring system, a permanent monitoring system, able to follow the phenomenon evolution, was set up. The system was progressively expanded and it is still running. The monitoring network is made up of an automatic total station and a network of wire - extensometers. This coupled measuring system was designed to make monitoring possible even in bad atmospheric conditions Then the monitoring network was expanded with the addition of a borehole inclinometer and a piezometer. Continuous monitoring brings added value for both emergencies management and the study of the dynamical evolution of the phenomenon. As far as phenomena that are subject to seasonal reactivations are concerned, the use of monitoring systems brings a significant improvement of knowledge. This proves to be even more useful during the risk mitigation phase than during the study of the evolutionary trends of the phenomena. The case of Gardiola demonstrated how a careful analysis of the phenomenon makes possible an effective management of the most critical moments, together with a careful design of effective and not expensive mitigation works. Data provided by the monitoring system allowed the realisation of less expensive and less invasive facilities that work only during the acme of the phenomenon

Investigating landslides caused by earthquakes - A historical review

USGS Publications Warehouse

Keefer, D.K.

2002-01-01

Post-earthquake field investigations of landslide occurrence have provided a basis for understanding, evaluating, and mapping the hazard and risk associated with earthquake-induced landslides. This paper traces the historical development of knowledge derived from these investigations. Before 1783, historical accounts of the occurrence of landslides in earthquake are typically so incomplete and vague that conclusions based on these accounts are of limited usefulness. For example, the number of landslides triggered by a given event is almost always greatly underestimated. The first formal, scientific post-earthquake investigation that included systematic documentation of the landslides was undertaken in the Calabria region of Italy after the 1783 earthquake swarm. From then until the mid-twentieth century, the best information on earthquake-induced landslides came from a succession of post-earthquake investigations largely carried out by formal commissions that undertook extensive ground-based field studies. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, comprehensive inventories of landslide occurrence have been made for several earthquakes in the United States, Peru, Guatemala, Italy, El Salvador, Japan, and Taiwan. Techniques have also been developed for performing "retrospective" analyses years or decades after an earthquake that attempt to reconstruct the distribution of landslides triggered by the event. The additional use of Geographic Information System (GIS) processing and digital mapping since about 1989 has greatly facilitated the level of analysis that can applied to mapped distributions of landslides. Beginning in 1984, synthesis of worldwide and national data on earthquake-induced landslides have defined their general characteristics and relations between their occurrence and various geologic and seismic parameters. However, the number of comprehensive post-earthquake studies of landslides is still

Investigating Landslides Caused by Earthquakes A Historical Review

NASA Astrophysics Data System (ADS)

Keefer, David K.

Post-earthquake field investigations of landslide occurrence have provided a basis for understanding, evaluating, and mapping the hazard and risk associated withearthquake-induced landslides. This paper traces thehistorical development of knowledge derived from these investigations. Before 1783, historical accounts of the occurrence of landslides in earthquakes are typically so incomplete and vague that conclusions based on these accounts are of limited usefulness. For example, the number of landslides triggered by a given event is almost always greatly underestimated. The first formal, scientific post-earthquake investigation that included systematic documentation of the landslides was undertaken in the Calabria region of Italy after the 1783 earthquake swarm. From then until the mid-twentieth century, the best information on earthquake-induced landslides came from a succession ofpost-earthquake investigations largely carried out by formal commissions that undertook extensive ground-based field studies. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, comprehensive inventories of landslide occurrence have been made for several earthquakes in the United States, Peru, Guatemala, Italy, El Salvador, Japan, and Taiwan. Techniques have also been developed for performing ``retrospective'' analyses years or decades after an earthquake that attempt to reconstruct the distribution of landslides triggered by the event. The additional use of Geographic Information System (GIS) processing and digital mapping since about 1989 has greatly facilitated the level of analysis that can applied to mapped distributions of landslides. Beginning in 1984, syntheses of worldwide and national data on earthquake-induced landslides have defined their general characteristics and relations between their occurrence and various geologic and seismic parameters. However, the number of comprehensive post-earthquake studies of landslides is still

9. Excavation work at Pleasant Dam (now called Waddell Dam). ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. Excavation work at Pleasant Dam (now called Waddell Dam). Photographer unknown, July, 22, 1926. Source: Maricopa County Municipal Water Conservation District Number One (MWD). - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

32. AERIAL VIEW OF TIETON DAM, UPSTREAM FACE OF DAM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. AERIAL VIEW OF TIETON DAM, UPSTREAM FACE OF DAM (Trashrack-structure for outlet at lower left in reservoir, spillway at upper left. Reservoir nearly empty due to drought.) - Tieton Dam, South & East of State Highway 12, Naches, Yakima County, WA

Cross-slope Movement Patterns in Landslides

NASA Astrophysics Data System (ADS)

Petley, D.; Murphy, W.; Bulmer, M. H.; Keefer, D.

2002-12-01

There is growing evidence that there is a significant element of cross-slope movement in many large landslide systems. These movements may result in changing states of stress between landslide blocks that can establish complex displacement patterns. Such motions, which are not considered in traditional two-dimensional limit-equilibrium analyses, are important in the investigation of a variety of landslide types, such as those triggered by earthquakes. In addition, these movements may introduce considerable errors into the interpretation of strain patterns as derived from InSAR studies. Finally, even traditional interpretation techniques may lead to the amount of total displacement being underestimated. These observations suggest that a three dimensional form of analysis may be more appropriate for large landslide complexes. The significance of such cross-slope movements are being investigated using a detailed investigation of the Lishan landslide complex in Central Taiwan. This landslide system, which was reactivated in 1990 related to the construction of a hotel. The total recorded movements have been approximately 1.5 m over an area of sliding that is estimated to be 450 m wide and 200 m long. Extensive damage has been caused to roads and buildings within the town. Remediation work has resulted largely in the stabilization of the landslide complex. Detailed geomorphological mapping has revealed that the landslide complex is composed of two main components. The first, immediately upslope of the hotel construction site, is a relatively shallow earthflow. The second, which has formed a large headscarp upslope from the main road in the centre of the town, is a deeper translational slide. Both appear to have been reactivations of previous failures. While the displacement patterns of the earthflow indicate a relatively simple downslope movement, the vectors derived from kinematic analysis of surface features have indicated that the movement of the deeper

Landslide Hazard Mapping in Rwanda Using Logistic Regression

NASA Astrophysics Data System (ADS)

Piller, A.; Anderson, E.; Ballard, H.

2015-12-01

Landslides in the United States cause more than $1 billion in damages and 50 deaths per year (USGS 2014). Globally, figures are much more grave, yet monitoring, mapping and forecasting of these hazards are less than adequate. Seventy-five percent of the population of Rwanda earns a living from farming, mostly subsistence. Loss of farmland, housing, or life, to landslides is a very real hazard. Landslides in Rwanda have an impact at the economic, social, and environmental level. In a developing nation that faces challenges in tracking, cataloging, and predicting the numerous landslides that occur each year, satellite imagery and spatial analysis allow for remote study. We have focused on the development of a landslide inventory and a statistical methodology for assessing landslide hazards. Using logistic regression on approximately 30 test variables (i.e. slope, soil type, land cover, etc.) and a sample of over 200 landslides, we determine which variables are statistically most relevant to landslide occurrence in Rwanda. A preliminary predictive hazard map for Rwanda has been produced, using the variables selected from the logistic regression analysis.

A seismic landslide susceptibility rating of geologic units based on analysis of characterstics of landslides triggered by the 17 January, 1994 Northridge, California earthquake

USGS Publications Warehouse

Parise, M.; Jibson, R.W.

2000-01-01

One of the most significant effects of the 17 January, 1994 Northridge, California earthquake (M=6.7) was the triggering of thousands of landslides over a broad area. Some of these landslides damaged and destroyed homes and other tructures, blocked roads, disrupted pipelines, and caused other serious damage. Analysis of the distribution and characteristics of these landslides is important in understanding what areas may be susceptible to landsliding in future earthquakes. We analyzed the frequency, distribution, and geometries of triggered landslides in the Santa Susana 7.5??? quadrangle, an area of intense seismic landslide activity near the earthquake epicenter. Landslides occured primarily in young (Late Miocene through Pleistocene) uncemented or very weakly cemented sediment that has been repeatedly folded, faulted, and uplifted in the past 1.5 million years. The most common types of landslide triggered by the earthquake were highly disrupted, shallow falls and slides of rock and debris. Far less numerous were deeper, more coherent slumps and block slides, primarily occuring in more cohesive or competent materials. The landslides in the Santa Susana quadrangle were divided into two samples: single landslides (1502) and landslide complexes (60), which involved multiple coalescing failures of surficial material. We described landslide, morphologies by computing simple morphometric parameters (area, length, width, aspect ratio, slope angle). To quantify and rank the relative susceptibility of each geologic unit to seismic landsliding, we calculated two indices: (1) the susceptibility index, which is the ratio (given as a percentage) of the area covered by landslide sources within a geologic unit to the total outcrop area of that unit: and (2) the frequency index [given in landslides per square kilometer (ls/km2)], which is the total number of landslides within each geologic unit divided by the outcrop area of that unit. Susceptibility categories include very high

Post failure behaviour of landslide bodies: the large Montescaglioso landslide of 2013 dec

NASA Astrophysics Data System (ADS)

Spilotro, Giuseppe; Ermini, Ruggero; Sdao, Francesco; Pellicani, Roberta

2015-04-01

After a period of intense rains, on 3 December 2013, already from the day before preceded by several warning signals, a landslide of about 800 m in length, 700 m wide, maximum depth of 40 m, with a total surface area of the first detachment body of 500,000 square meters (50 ha) and volume of about 3 million cubic meters was mobilized from the slopes south of Montescaglioso (MT, Italy). The body was moved towards the south of about 20 m, stopping against the opposite bank of a deep ditch. The distension caused by this movement triggered the movement of additional plates in the upper part of the slope, extending the total surface interested by the instability phenomenon. Despite the extensive damage to houses and commercial buildings, no casualties occurred. The studies and monitoring of sensible parameters, carried out after the landslide movement, revealed numerous specificities prodromal to the landslide phenomenon: a stratigraphic context, even if simple, but disrupted by late-Pleistocene tectonics and by the eustatic deepening of the base level of the hydrography; a widespread aquifer over the entire surface of the landslide body inside the sandy and conglomeratic covering layers; the groundwater flow which revealed the same direction of the landslide displacement; finally, a river network strongly deformed from its natural configuration, with reduced efficiency compared to outflow and increased compared to the process of infiltration. In the distribution of the points of weakness, whose coalescence enveloped the large surface of the landslide, are to be recorded: processes of loss of cementation by sandy and conglomeratic soils; loss of soil matrix operated by groundwater flow in the stretch near the clayey bedrock; interaction of the stiff blue clays with low salinity fluids at the foot of the landslide and elsewhere. The result was a rapid movement of a rigid body, which allowed to recognize a process of progressive failure. The mean shear strength mobilized

Landslide in Mutch

NASA Technical Reports Server (NTRS)

2005-01-01

18 November 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the east margin of a landslide off the southern rim of Mutch Crater in the Xanthe Terra region of Mars. This particular landslide was likely triggered by a meteor impact that occurred nearby.

Location near: 0.7oS, 55.9oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Spring

Analysis of national and regional landslide inventories in Europe

NASA Astrophysics Data System (ADS)

Hervás, J.; Van Den Eeckhaut, M.

2012-04-01

A landslide inventory can be defined as a detailed register of the distribution and characteristics of past landslides in an area. Today most landslide inventories have the form of digital databases including landslide distribution maps and associated alphanumeric information for each landslide. While landslide inventories are of the utmost importance for land use planning and risk management through the generation of landslide zonation (susceptibility, hazard and risk) maps, landslide databases are thought to greatly differ from one country to another and often also within the same country. This hampers the generation of comparable, harmonised landslide zonation maps at national and continental scales, which is needed for policy and decision making at EU level as regarded for instance in the INSPIRE Directive and the Thematic Strategy for Soil Protection. In order to have a clear understanding of the landslide inventories available in Europe and their potential to produce landslide zonation maps as well as to draw recommendations to improve harmonisation and interoperability between landslide databases, we have surveyed 37 countries. In total, information has been collected and analysed for 24 national databases in 22 countries (Albania, Andorra, Austria, Bosnia and Herzegovina, Bulgaria, Czech Republic, Former Yugoslav Republic of Macedonia, France, Greece, Hungary, Iceland, Ireland, Italy, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and UK) and 22 regional databases in 10 countries. At the moment, over 633,000 landslides are recorded in national databases, representing on average less than 50% of the estimated landslides occurred in these countries. The sample of regional databases included over 103,000 landslides, with an estimated completeness substantially higher than that of national databases, as more attention can be paid for data collection over smaller regions. Yet, both for national and regional coverage, the data collection

Design of Installing Check Dam Using RAMMS Model in Seorak National Park of South Korea

NASA Astrophysics Data System (ADS)

Jun, K.; Tak, W.; JUN, B. H.; Lee, H. J.; KIM, S. D.

2016-12-01

Design of Installing Check Dam Using RAMMS Model in Seorak National Park of South Korea Kye-Won Jun*, Won-Jun Tak*, Byong-Hee Jun**, Ho-Jin Lee***, Soung-Doug Kim* *Graduate School of Disaster Prevention, Kangwon National University, 346 Joogang-ro, Samcheok-si, Gangwon-do, Korea **School of Fire and Disaster Protection, Kangwon National University, 346 Joogang-ro, Samcheok-si, Gangwon-do, Korea ***School of Civil Engineering, Chungbuk National University, 1 Chungdae-ro, Seowon-gu, Cheongju, Korea Abstract As more than 64% of the land in South Korea is mountainous area, so many regions in South Korea are exposed to the danger of landslide and debris flow. So it is important to understand the behavior of debris flow in mountainous terrains, the various methods and models are being presented and developed based on the mathematical concept. The purpose of this study is to investigate the regions that experienced the debris flow due to typhoon called Ewiniar and to perform numerical modeling to design and layout of the Check dam for reducing the damage by the debris flow. For the performance of numerical modeling, on-site measurement of the research area was conducted including: topographic investigation, research on bridges in the downstream, and precision LiDAR 3D scanning for composed basic data of numerical modeling. The numerical simulation of this study was performed using RAMMS (Rapid Mass Movements Simulation) model for the analysis of the debris flow. This model applied to the conditions of the Check dam which was installed in the upstream, midstream, and downstream. Considering the reduction effect of debris flow, the expansion of debris flow, and the influence on the bridges in the downstream, proper location of the Check dam was designated. The result of present numerical model showed that when the Check dam was installed in the downstream section, 50 m above the bridge, the reduction effect of the debris flow was higher compared to when the Check dam were

Landslides

NASA Image and Video Library

2003-04-02

The slumping of materials in the walls of this impact crater imaged by NASA Mars Odyssey spacecraft illustrates the continued erosion of the Martian surface. Small fans of debris as well as larger landslides are observed throughout the image.

Landslides and engineering geology of the Seattle, Washington, area

USGS Publications Warehouse

Baum, Rex L.; Godt, Jonathan W.; Highland, Lynn M.

2008-01-01

This volume brings together case studies and summary papers describing the application of state-of-the-art engineering geologic methods to landslide hazard analysis for the Seattle, Washington, area. An introductory chapter provides a thorough description of the Quaternary and bedrock geology of Seattle. Nine additional chapters review the history of landslide mapping in Seattle, present case studies of individual landslides, describe the results of spatial assessments of landslide hazard, discuss hydrologic controls on landsliding, and outline an early warning system for rainfall-induced landslides.

Regional landslide-hazard assessment for Seattle, Washington, USA

USGS Publications Warehouse

Baum, R.L.; Coe, J.A.; Godt, J.W.; Harp, E.L.; Reid, M.E.; Savage, W.Z.; Schulz, W.H.; Brien, D.L.; Chleborad, A.F.; McKenna, J.P.; Michael, J.A.

2005-01-01

Landslides are a widespread, frequent, and costly hazard in Seattle and the Puget Sound area of Washington State, USA. Shallow earth slides triggered by heavy rainfall are the most common type of landslide in the area; many transform into debris flows and cause significant property damage or disrupt transportation. Large rotational and translational slides, though less common, also cause serious property damage. The hundreds of landslides that occurred during the winters of 1995-96 and 1996-97 stimulated renewed interest by Puget Sound communities in identifying landslide-prone areas and taking actions to reduce future landslide losses. Informal partnerships between the U.S. Geological Survey (USGS), the City of Seattle, and private consultants are focusing on the problem of identifying and mapping areas of landslide hazard as well as characterizing temporal aspects of the hazard. We have developed GIS-based methods to map the probability of landslide occurrence as well as empirical rainfall thresholds and physically based methods to forecast times of landslide occurrence. Our methods for mapping landslide hazard zones began with field studies and physically based models to assess relative slope stability, including the effects of material properties, seasonal groundwater levels, and rainfall infiltration. We have analyzed the correlation between historic landslide occurrence and relative slope stability to map the degree of landslide hazard. The City of Seattle is using results of the USGS studies in storm preparedness planning for emergency access and response, planning for development or redevelopment of hillsides, and municipal facility planning and prioritization. Methods we have developed could be applied elsewhere to suit local needs and available data.

Landslides triggered by the 1994 Northridge, California, earthquake

USGS Publications Warehouse

Harp, E.L.; Jibson, R.W.

1996-01-01

The 17 January 1994 Northridge, California, earthquake (Mw, = 6.7) triggered more than 11,000 landslides over an area of about 10,000 km2. Most of the landslides were concentrated in a 1000-km2 area that included the Santa Susana Mountains and the mountains north of the Santa Clara River valley. We mapped landslides triggered by the earthquake in the field and from 1:60,000-nominal-scale aerial photography provided by the U.S. Air Force and taken the morning of the earthquake; these mapped landslides were subsequently digitized and plotted in a GIS-based format. Most of the triggered landslides were shallow (1- to 5-m thick), highly disrupted falls and slides within weakly cemented Tertiary to Pleistocene clastic sediment. Average volumes of these types of landslides were less than 1000 m3, but many had volumes exceeding 100,000 m3. The larger disrupted slides commonly had runout paths of more than 50 m, and a few traveled as far as 200 m from the bases of steep parent slopes. Deeper (>5-m thick) rotational slumps and block slides numbered in the tens to perhaps hundreds, a few of which exceeded 100,000 m3 in volume. Most of these were reactivations of previously existing landslides. The largest single landslide triggered by the earthquake was a rotational slump/block slide having a volume of 8 ?? 106 m3. Analysis of the mapped landslide distribution with respect to variations in (1) landslide susceptibility and (2) strong shaking recorded by hundreds of instruments will form the basis of a seismic landslide hazard analysis of the Los Angeles area.

Landslide Inventory and Susceptibility Mapping in Tropical Areas - Southern Mexico

NASA Astrophysics Data System (ADS)

Gaidzik, K.; Ramirez-Herrera, M. T.; Regmi, N. R.; Leshchinsky, B. A.

2016-12-01

Landslides are one of the common catastrophic phenomena in the world. In regions of humid-warm tropical climate they are triggered by extreme storms causing loss of life and economic devastation. In this study we mapped susceptibility to landslides in the tropical mountains of Guerrero (South Mexico) based on the inventory of landslide features triggered by the hurricane Manuel of September 2013. Landslide inventory was produced using interpretation of satellite images and automatic identification of landslides employing the Contour Connection Method (CCM). A map of susceptibility to landslides was developed by computing probability of landslide occurrence from statistical relationships of existing landslides using LiDAR elevation model and derived landslide-causing factors using a logistic regression method. Landslide inventory includes 419 features produced by the hurricane Manuel on the area of 22 km2, and > 1,000 older features, suggesting high landslide activity in this area. Most landslides in the region are small, but some large slides exist, such as the catastrophic landslide in La Pintada that caused 71 fatalities and destroyed a large part of the village. Our results indicate that the distance to streams, human activity, presence or absence of dense vegetation and orientation of slopes (on some areas) strongly influence the spatial distribution of landslides. Results showed high susceptibility zones encompass 30% of the study area and occur mostly along topographic convergence. Applied approach identified most of the landslides within the high susceptibility zone and suggested that it is a valid applicable method to map areas susceptible to landslides in southern Mexico but also on other humid-warm tropical regions.

Investigating Earthquake-induced Landslides­a Historical Review

NASA Astrophysics Data System (ADS)

Keefer, D. K.; Geological Survey, Us; Park, Menlo; Usa, Ca

Although earthquake-induced landslides have been described in documents for more than 3700 years, accounts from earthquakes before the late eighteenth century are incomplete concerning landslide numbers and vague concerning landslide character- istics. They are thus typically misleading concerning the true abundance of landslides and range of landslide characteristics. Beginning with studies of the 1783 Calabria, Italy earthquake, more complete and precise data concerning the occurrence of land- slides in earthquakes have become available. The historical development of knowl- edge concerning landslides triggered by earthquakes can be divided into several peri- ods. The first period, from 1783 until the first application of aerial photography, was characterized by ground-based studies of earthquake effects, typically carried out by formal scientific commissions. These formal studies typically identified a large, but not necessarily comprehensive, sampling of localities where landslides had occurred. In some, but not all cases, landslide characteristics were also described in enough de- tail that the general range of landslide characteristics could begin to be determined. More recently, some nineteenth to mid-twentieth century earthquakes have been stud- ied using retrospective analyses, in which the landslide occurrences associated with the event are inferred years to decades later, using contemporary accounts, mapping from aerial photographs, statistical studies, and (or) geotechnical analyses. The first use of aerial photographs to map earthquake effects immediately after the event prob- ably occurred in 1948. Since that time, the use of aerial photography has greatly facil- itated the compilation of post-earthquake landslide inventories, although because of the limitations of aerial photography, ground-based field studies continue to be cru- cial in preparing accurate and comprehensive landslide maps. Beginning with a small California earthquake in 1957

Modelling the Probability of Landslides Impacting Road Networks

NASA Astrophysics Data System (ADS)

Taylor, F. E.; Malamud, B. D.

2012-04-01

During a landslide triggering event, the threat of landslides blocking roads poses a risk to logistics, rescue efforts and communities dependant on those road networks. Here we present preliminary results of a stochastic model we have developed to evaluate the probability of landslides intersecting a simple road network during a landslide triggering event and apply simple network indices to measure the state of the road network in the affected region. A 4000 x 4000 cell array with a 5 m x 5 m resolution was used, with a pre-defined simple road network laid onto it, and landslides 'randomly' dropped onto it. Landslide areas (AL) were randomly selected from a three-parameter inverse gamma probability density function, consisting of a power-law decay of about -2.4 for medium and large values of AL and an exponential rollover for small values of AL; the rollover (maximum probability) occurs at about AL = 400 m2 This statistical distribution was chosen based on three substantially complete triggered landslide inventories recorded in existing literature. The number of landslide areas (NL) selected for each triggered event iteration was chosen to have an average density of 1 landslide km-2, i.e. NL = 400 landslide areas chosen randomly for each iteration, and was based on several existing triggered landslide event inventories. A simple road network was chosen, in a 'T' shape configuration, with one road 1 x 4000 cells (5 m x 20 km) in a 'T' formation with another road 1 x 2000 cells (5 m x 10 km). The landslide areas were then randomly 'dropped' over the road array and indices such as the location, size (ABL) and number of road blockages (NBL) recorded. This process was performed 500 times (iterations) in a Monte-Carlo type simulation. Initial results show that for a landslide triggering event with 400 landslides over a 400 km2 region, the number of road blocks per iteration, NBL,ranges from 0 to 7. The average blockage area for the 500 iterations (A¯ BL) is about 3000 m

Landslide database dominated by rainfall triggered events

NASA Astrophysics Data System (ADS)

Devoli, G.; Strauch, W.; Álvarez, A.

2009-04-01

A digital landslide database has been created for Nicaragua to provide the scientific community and national authorities with a tool for landslide hazard assessment. Valuable information on landslide events has been obtained from a great variety of sources. On the basis of the data stored in the database, preliminary analyses performed at national scale aimed to characterize landslides in terms of spatial and temporal distribution, types of slope movements, triggering mechanisms, number of casualties and damage to infrastructure. A total of about 17000 events spatially distributed in mountainous and volcanic terrains have been collected in the database. The events are temporally distributed between 1826 and 2003, but a large number of the records (62% of the total number) occurred during the disastrous Hurricane Mitch in October 1998. The results showed that debris flows are the most common types of landslides recorded in the database (66% of the total amount), but other types, including rockfalls and slides, have also been identified. Rainfall, also associated with tropical cyclones, is the most frequent triggering mechanism of landslides in Nicaragua, but also seismic and volcanic activities are important triggers or, especially, the combination of one of them with rainfall. Rainfall has caused all types of failures, but debris flows and translational shallow slides are more frequent types. Earthquakes have most frequently triggered rockfalls and slides, while volcanic eruptions rockfalls and debris flows. Landslides triggered by rainfall were limited in time to the wet season that lasts from May to October and an increase in the number of events is observed during the months of September and October, which is in accord with the period of the rainy season in the Pacific and Northern and Central regions and when the country has the highest probability of being impacted by hurricanes. Both Atlantic and Pacific tropical cyclones have triggered landslides. At the

Integration of landslide susceptibility products in the environmental plans

NASA Astrophysics Data System (ADS)

Fiorucci, Federica; Reichenbach, Paola; Rossi, Mauro; Cardinali, Mauro; Guzzetti, Fausto

2015-04-01

Landslides are one of the most destructive natural hazard that causes damages to urban area worldwide. The knowledge of where a landslide could occur is essential for the strategic management of the territory and for a good urban planning . In this contest landslide susceptibility zoning (LSZ) is crucial to provide information on the degree to which an area can be affected by future slope movements. Despite landslide susceptibility maps have been prepared extensively during the last decades, there are few examples of application is in the environmental plans (EP). In this work we present a proposal for the integration of the landslide inventory map with the following landslide susceptibility products: (i) landslide susceptibility zonation , (ii) the associated error map and (iii) the susceptibility uncertainty map. Moreover we proposed to incorporate detailed morphological studies for the evaluation of landslide risk associated to local parceling plan. The integration of all this information is crucial for the management of landslide risk in urban expansions forecasts. Municipality, province and regional administration are often not able to support the costs of landslide risk evaluation for extensive areas but should concentrate their financial resources to specific hazardous and unsafe situations defined by the result of the integration of landslide susceptibility products. Zonation and detail morphological analysis should be performed taking into account the existing laws and regulations, and could become a starting point to discuss new regulations for the landslide risk management.

Real-time landslide warning during heavy rainfall

USGS Publications Warehouse

Keefer, D.K.; Wilson, R.C.; Mark, R.K.; Brabb, E.E.; Brown, W. M.; Ellen, S.D.; Harp, E.L.; Wieczorek, G.F.; Alger, C.S.; Zatkin, R.S.

1987-01-01

A real-time system for issuing warnings of landslides during major storms is being developed for the San Francisco Bay region, California. The system is based on empirical and theoretical relations between rainfall and landslide initiation, geologic determination of areas susceptible to landslides, real-time monitoring of a regional network of telemetering rain gages, and National Weather Service precipitation forecasts. This system was used to issue warnings during the storms of 12 to 21 February 1986, which produced 800 millimeters of rainfall in the region. Although analysis after the storms suggests that modifications and additional developments are needed, the system successfully predicted the times of major landslide events. It could be used as a prototype for systems in other landslide-prone regions.

Landslide susceptibility mapping using a neuro-fuzzy

NASA Astrophysics Data System (ADS)

Lee, S.; Choi, J.; Oh, H.

2009-12-01

This paper develops and applied an adaptive neuro-fuzzy inference system (ANFIS) based on a geographic information system (GIS) environment using landslide-related factors and location for landslide susceptibility mapping. A neuro-fuzzy system is based on a fuzzy system that is trained by a learning algorithm derived from the neural network theory. The learning procedure operates on local information, and causes only local modifications in the underlying fuzzy system. The study area, Boun, suffered much damage following heavy rain in 1998 and was selected as a suitable site for the evaluation of the frequency and distribution of landslides. Boun is located in the central part of Korea. Landslide-related factors such as slope, soil texture, wood type, lithology, and density of lineament were extracted from topographic, soil, forest, and lineament maps. Landslide locations were identified from interpretation of aerial photographs and field surveys. Landslide-susceptible areas were analyzed by the ANFIS method and mapped using occurrence factors. In particular, we applied various membership functions (MFs) and analysis results were verified using the landslide location data. The predictive maps using triangular, trapezoidal, and polynomial MFs were the best individual MFs for modeling landslide susceptibility maps (84.96% accuracy), proving that ANFIS could be very effective in modeling landslide susceptibility mapping. Various MFs were used in this study, and after verification, the difference in accuracy according to the MFs was small, between 84.81% and 84.96%. The difference was just 0.15% and therefore the choice of MFs was not important in the study. Also, compared with the likelihood ratio model, which showed 84.94%, the accuracy was similar. Thus, the ANFIS could be applied to other study areas with different data and other study methods such as cross-validation. The developed ANFIS learns the if-then rules between landslide-related factors and landslide

Rainfall-induced landslides in Puerto Rico: An overview

USGS Publications Warehouse

Pando, M.A.; Ruiz, M.E.; Larsen, M.C.

2005-01-01

Rainfall-induced landslides are common in Puerto Rico (PR). The presence of steep slopes in mountainous terrain, coupled with weathered soils and intense rainfall, leads to severe slope-stability problems throughout the island. Episodic triggering events such as hurricanes and earthquakes further exacerbate these problems. All physiographic provinces of the island have experienced landslides. The stability of natural and man-made slopes is a serious concern for government authorities and the civil engineering community in Puerto Rico. This paper presents an overview of the rainfall induced landslide problem in PR, a summary of literature published on this subject, and proposes a rainfall intensity landslide threshold based on landslide events data from 1959 to 2003. This threshold can be used as part of a potential landslide warning system.

Landslide Hazard Assessment and Mapping in the Guil Catchment (Queyras, Southern French Alps): From Landslide Inventory to Susceptibility Modelling

NASA Astrophysics Data System (ADS)

Roulleau, Louise; Bétard, François; Carlier, Benoît; Lissak, Candide; Fort, Monique

2016-04-01

Landslides are common natural hazards in the Southern French Alps, where they may affect human lives and cause severe damages to infrastructures. As a part of the SAMCO research project dedicated to risk evaluation in mountain areas, this study focuses on the Guil river catchment (317 km2), Queyras, to assess landslide hazard poorly studied until now. In that area, landslides are mainly occasional, low amplitude phenomena, with limited direct impacts when compared to other hazards such as floods or snow avalanches. However, when interacting with floods during extreme rainfall events, landslides may have indirect consequences of greater importance because of strong hillslope-channel connectivity along the Guil River and its tributaries (i.e. positive feedbacks). This specific morphodynamic functioning reinforces the need to have a better understanding of landslide hazards and their spatial distribution at the catchment scale to prevent local population from disasters with multi-hazard origin. The aim of this study is to produce a landslide susceptibility mapping at 1:50 000 scale as a first step towards global estimation of landslide hazard and risk. The three main methodologies used for assessing landslide susceptibility are qualitative (i.e. expert opinion), deterministic (i.e. physics-based models) and statistical methods (i.e. probabilistic models). Due to the rapid development of geographical information systems (GIS) during the last two decades, statistical methods are today widely used because they offer a greater objectivity and reproducibility at large scales. Among them, multivariate analyses are considered as the most robust techniques, especially the logistic regression method commonly used in landslide susceptibility mapping. However, this method like others is strongly dependent on the accuracy of the input data to avoid significant errors in the final results. In particular, a complete and accurate landslide inventory is required before the modelling

Landslide susceptibility revealed by LIDAR imagery and historical records, Seattle, Washington

USGS Publications Warehouse

Schulz, W.H.

2007-01-01

Light detection and ranging (LIDAR) data were used to visually map landslides, headscarps, and denuded slopes in Seattle, Washington. Four times more landslides were mapped than by previous efforts that used aerial photographs. The mapped landforms (landslides, headscarps, and denuded slopes) were created by many individual landslides. The spatial distribution of mapped landforms and 1308 historical landslides show that historical landslide activity has been concentrated on the mapped landforms, and that most of the landslide activity that created the landforms was prehistoric. Thus, the spatial densities of historical landslides on the landforms provide approximations of the landforms' relative susceptibilities to future landsliding. Historical landslide characteristics appear to be closely related to landform type so relative susceptibilities were determined for landslides with various characteristics. No strong relations were identified between stratigraphy and landslide occurrence; however, landslide characteristics and slope morphology appear to be related to stratigraphic conditions. Human activity is responsible for causing about 80% of historical Seattle landslides. The distribution of mapped landforms and human-caused landslides suggests the probable characteristics of future human-caused landslides on each of the landforms. The distribution of mapped landforms and historical landslides suggests that erosion of slope-toes by surface water has been a necessary condition for causing Seattle landslides. Human activity has largely arrested this erosion, which implies that landslide activity will decrease with time as hillsides naturally stabilize. However, evaluation of glacial-age analogs of areas of recent slope-toe erosion suggests that landslide activity in Seattle will continue for the foreseeable future. ?? 2006 Elsevier B.V. All rights reserved.

A review of mechanisms and modelling procedures for landslide tsunamis

NASA Astrophysics Data System (ADS)

Løvholt, Finn; Harbitz, Carl B.; Glimsdal, Sylfest

2017-04-01

Landslides, including volcano flank collapses or volcanically induced flows, constitute the second-most important cause of tsunamis after earthquakes. Compared to earthquakes, landslides are more diverse with respect to how they generation tsunamis. Here, we give an overview over the main tsunami generation mechanisms for landslide tsunamis. In the presentation, a mix of results using analytical models, numerical models, laboratory experiments, and case studies are used to illustrate the diversity, but also to point out some common characteristics. Different numerical modelling techniques for the landslide evolution, and the tsunami generation and propagation, as well as the effect of frequency dispersion, are also briefly discussed. Basic tsunami generation mechanisms for different types of landslides, including large submarine translational landslide, to impulsive submarine slumps, and violent subaerial landslides and volcano flank collapses, are reviewed. The importance of the landslide kinematics is given attention, including the interplay between landslide acceleration, landslide velocity to depth ratio (Froude number) and dimensions. Using numerical simulations, we demonstrate how landslide deformation and retrogressive failure development influence tsunamigenesis. Generation mechanisms for subaerial landslides, are reviewed by means of scaling relations from laboratory experiments and numerical modelling. Finally, it is demonstrated how the different degree of complexity in the landslide tsunamigenesis needs to be reflected by increased sophistication in numerical models.

Climate-physiographically differentiated Pan-European landslide susceptibility assessment using spatial multi-criteria evaluation and transnational landslide information

NASA Astrophysics Data System (ADS)

Günther, Andreas; Van Den Eeckhaut, Miet; Malet, Jean-Philippe; Reichenbach, Paola; Hervás, Javier

2014-11-01

With the adoption of the EU Thematic Strategy for Soil Protection in 2006, small-scale (1:1 M) assessments of threats affecting soils over Europe received increasing attention. As landslides have been recognized as one of eight threats requiring a Pan-European evaluation, we present an approach for landslide susceptibility evaluation at the continental scale over Europe. Unlike previous continental and global scale landslide susceptibility studies not utilizing spatial information on the events, we collected more than 102,000 landslide locations in 22 European countries. These landslides are heterogeneously distributed over Europe, but are indispensable for the evaluation and classification of Pan-European datasets used as spatial predictors, and the validation of the resulting assessments. For the analysis we subdivided the European territory into seven different climate-physiographical zones by combining morphometric and climatic data for terrain differentiation, and adding a coastal zone defined as a 1 km strip inland from the coastline. Landslide susceptibility modeling was performed for each zone using heuristic spatial multicriteria evaluations supported by analytical hierarchy processes, and validated with the inventory data using the receiver operating characteristics. In contrast to purely data-driven statistical modeling techniques, our semi-quantitative approach is capable to introduce expert knowledge into the analysis, which is indispensable considering quality and resolution of the input data, and incompleteness and bias in the inventory information. The reliability of the resulting susceptibility map ELSUS 1000 Version 1 (1 km resolution) was examined on an administrative terrain unit level in areas with landslide information and through the comparison with available national susceptibility zonations. These evaluations suggest that although the ELSUS 1000 is capable for a correct synoptic prediction of landslide susceptibility in the majority of the

Landslides in the New Madrid seismic zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jibson, R.W.; Keefer, D.K.

1985-01-01

During the New Madrid earthquakes of 1811-12, bluffs bordering the Mississippi alluvial plain in the epicentral region underwent large-scale landsliding. Between Cairo, Illinois and Memphis, Tennessee, the authors mapped 221 large landslides of three types: (1) old, eroded, coherent block slides and slumps; (2) old earth flows; and (3) young, fresh slumps that occur only along near-river bluffs and are the only landslides present along such bluffs. Historical accounts and field evidence indicate that most or all old coherent slides and earth flows date to the 1811-12 earthquakes and that the only currently active, large-scale landsliding in the area occursmore » along bluffs bordering the river. Analysis of old coherent slides and earth flows indicates that landslide distribution is most strongly affected by slope height, but that proximity to the hypocenters of the 1811-12 earthquakes also has a significant effect. Slope-stability analyses of an old coherent slide and an earth flow selected as representative of the principal kinds of landslides present indicate that both were stable in aseismic conditions even when water tables were at highest possible levels. However, a dynamic Newmark displacement analysis shows that ground shaking such as that in 1811-12 would cause large displacements leading to catastrophic failure in both slides. These results indicate that in large earthquakes landsliding in much of the study are is likely. Moderate earthquakes may also trigger landslides at some locations.« less

Using soil properties as a tool to differentiate landslide generations and constrain their ages - Rogowiec landslide, Sudetes (SW Poland)

NASA Astrophysics Data System (ADS)

Kacprzak, Andrzej; Migoń, Piotr

2013-04-01

The Sudetes, at the border of Poland and the Czech Republic, are generally considered as a mountain range where landslides play a marginal geomorphic role. Only a few larger landslides have been recorded during historical times, mainly on steep valley sides undercut by rivers. Forested slopes, which dominate in the Sudetes, are usually inferred to be stable, except for near-surface bioturbation and localized accelerated surface erosion at sites subject to strong human impact. Large, apparently relict landslides in the Kamienne Mountains, Middle Sudetes, pose a considerable challenge to this view and two interpretations are possible. First, they may be indeed relict, pre-Holocene features that formed under different environmental conditions and have been completely stabilized since the origin. Second, they may be rare components of the contemporary (Holocene) geomorphic system but their frequency of occurrence is low and this is why none has been reported in written or oral records. If the second scenario captures the reality adequately, this would have significant implications for hazard and risk assessment. To address this issue, an extensive soil survey was carried out on the large landslide of Rogowiec, likely of complex flow nature as suggested by landform mapping. The rationale of the study involved an assumption that soil formation time in the area is limited to the Holocene, since harsh periglacial conditions typified the late Pleistocene. 15 soil pits were excavated within landslide terrain and on adjacent reference slopes which do not bear any evident traces of significant displacements. Despite the small area under investigation, the soil profiles are very diverse in terms of depth, horizonation, organic matter content, development of soil structure, as well as the content and lithology of coarse fragments. A great deal of this diversity can be explained by different duration of pedogenesis controlled by geomorphic processes. Very weakly developed soil

The comparison of landslide ratio-based and general logistic regression landslide susceptibility models in the Chishan watershed after 2009 Typhoon Morakot

NASA Astrophysics Data System (ADS)

WU, Chunhung

2015-04-01

The research built the original logistic regression landslide susceptibility model (abbreviated as or-LRLSM) and landslide ratio-based ogistic regression landslide susceptibility model (abbreviated as lr-LRLSM), compared the performance and explained the error source of two models. The research assumes that the performance of the logistic regression model can be better if the distribution of landslide ratio and weighted value of each variable is similar. Landslide ratio is the ratio of landslide area to total area in the specific area and an useful index to evaluate the seriousness of landslide disaster in Taiwan. The research adopted the landside inventory induced by 2009 Typhoon Morakot in the Chishan watershed, which was the most serious disaster event in the last decade, in Taiwan. The research adopted the 20 m grid as the basic unit in building the LRLSM, and six variables, including elevation, slope, aspect, geological formation, accumulated rainfall, and bank erosion, were included in the two models. The six variables were divided as continuous variables, including elevation, slope, and accumulated rainfall, and categorical variables, including aspect, geological formation and bank erosion in building the or-LRLSM, while all variables, which were classified based on landslide ratio, were categorical variables in building the lr-LRLSM. Because the count of whole basic unit in the Chishan watershed was too much to calculate by using commercial software, the research took random sampling instead of the whole basic units. The research adopted equal proportions of landslide unit and not landslide unit in logistic regression analysis. The research took 10 times random sampling and selected the group with the best Cox & Snell R2 value and Nagelkerker R2 value as the database for the following analysis. Based on the best result from 10 random sampling groups, the or-LRLSM (lr-LRLSM) is significant at the 1% level with Cox & Snell R2 = 0.190 (0.196) and Nagelkerke R2

An illustrated landslide handbook for developing nations

USGS Publications Warehouse

Highland, Lynn M.; Bobrowsky, Peter

2008-01-01

As landslides continue to be a hazard that account for large numbers of human and animal casualties, property loss, and infrastructure damage, as well as impacts on the natural environment, it is incumbent on developed nations that resources be allocated to educate affected populations in less developed nations, and provide them with tools to effectively manage this hazard. Given that the engineering, planning and zoning, and mitigation techniques for landslide hazard reduction are more accessible to developed nations, it is crucial that such landslide hazard management tools be communicated to less developed nations in a language that is not overly technical, and provides information on basic scientific explanations on where, why and how landslides occur. The experiences of the United States, Canada, and many other nations demonstrate that, landslide science education, and techniques for reducing damaging landslide impacts may be presented in a manner that can be understood by the layperson. There are various methods through which this may be accomplished–community-level education, technology transfer, and active one-on-one outreach to national and local governments, and non-governmental organizations (NGOs), who disseminate information throughout the general population. The population at large can also benefit from the dissemination of landslide information directly to individual community members. The United States Geological Survey and the Geological Survey of Canada have just published and will distribute a universal landslide handbook that can be easily made available to emergency managers, local governments, and individuals. The handbook, “The Landslide Handbook: A Guide to Understanding Landslides” is initially published as U.S. Geological Survey Circular 1325, in English, available in print, and accessible on the internet. It is liberally illustrated with schematics and photographs, and provides the means for a basic understanding of landslides, with

Landslides Triggered by the 2015 Gorkha, Nepal Earthquake

NASA Astrophysics Data System (ADS)

Xu, C.

2018-04-01

The 25 April 2015 Gorkha Mw 7.8 earthquake in central Nepal caused a large number of casualties and serious property losses, and also induced numerous landslides. Based on visual interpretation of high-resolution optical satellite images pre- and post-earthquake and field reconnaissance, we delineated 47,200 coseismic landslides with a total distribution extent more than 35,000 km2, which occupy a total area about 110 km2. On the basis of a scale relationship between landslide area (A) and volume (V), V = 1.3147 × A1.2085, the total volume of the coseismic landslides is estimated to be about 9.64 × 108 m3. Calculation yields that the landslide number density, area density, and volume density are 1.32 km-2, 0.31 %, and 0.027 m, respectively. The spatial distribution of these landslides is consistent with that of the mainshock and aftershocks and the inferred causative fault, indicating the effect of the earthquake energy release on the pattern on coseismic landslides. This study provides a new, more detailed and objective inventory of the landslides triggered by the Gorkha earthquake, which would be significant for further study of genesis of coseismic landslides, hazard assessment and the long-term impact of the slope failure on the geological environment in the earthquake-scarred region.

Multi-method characterization of a landslide in Champagne vineyards: the case study of the Jacotines landslide (Marne, France)

NASA Astrophysics Data System (ADS)

Nicolas, Bollot; Guillaume, Pierre; Gilles, Grandjean

2014-05-01

Key words : landslide, Champagne vineyards , geomorphology, geophysical data, superficial structure The Champagne region is strongly impacted by landslides. Usually inactive, these landslides suffer from partial reactivations leading to important damages, especially when they occur in the vineyards. In the Marne valley, and particularly in the center of Champagne vineyards area (Reuil), the Jacotines site is representative of such landslides since it presents typical surface characteristics widely observed in the region. However, its size, and especially its internal structure, can't be deduced from the surface analysis only. The aim of this work is to combine surface patterns analysis, geophysical data and borehole data to produce an interpretative model of the landslide. Preliminary geomorphological cartography was used for determining the influence of the landslide. From this information, geophysical investigations were carried out to image the internal structure of the landslide. Geophysical data fusion (combination of seismic and geoelectrical tomograms) was used to estimate the mechanical behavior and the fissuring pattern of the slope. Three transverse and longitudinal tomograms were used to define an heterogeneous area between 20 and 50 meters depth and a weathered zone from 0 to 10-20 meters depth. A 60 meters depth borehole on the main transverse tomogram found the shear plane and clarified the structure of the heterogeneous area as well as the uppermost weathered layer composed by debris flows resulting from partial reactivations processes.

Landslide

NASA Image and Video Library

2014-08-26

This image from NASA 2001 Mars Odyssey spacecraft shows a landslide deposit within a complex crater note the ejecta to the top and bottom of the image. There is a smaller complex crater on the ejecta to the north of the larger crater.

Landslide vulnerability criteria: a case study from Umbria, central Italy.

PubMed

Galli, Mirco; Guzzetti, Fausto

2007-10-01

Little is known about the vulnerability to landslides, despite landslides causing frequent and widespread damage to the population and the built-up environment in many areas of the world. Lack of information about vulnerability to landslides limits our ability to determine landslide risk. This paper provides information on the vulnerability of buildings and roads to landslides in Umbria, central Italy. Information on 103 landslides of the slide and slide-earth flow types that have resulted in damage to buildings and roads at 90 sites in Umbria is used to establish dependencies between the area of the landslide and the vulnerability to landslides. The dependencies obtained are applied in the hills surrounding the town of Collazzone, in central Umbria, an area for which a detailed landslide inventory map is available. By exploiting the landslide inventory and the established vulnerability curves, the geographical distribution of the vulnerability to landslides is mapped and statistics of the expected damage are calculated. Reliability and limits of the vulnerability thresholds and of the obtained vulnerability assessment are discussed.

Using a landslide inventory from online news to evaluate the performance of warning models for rainfall-induced landslides in Italy

NASA Astrophysics Data System (ADS)

Pecoraro, Gaetano; Calvello, Michele

2017-04-01

In Italy rainfall-induced landslides pose a significant and widespread hazard, resulting in a large number of casualties and enormous economic damages. Mitigation of such a diffuse risk cannot be attained with structural measures only. With respect to the risk to life, early warning systems represent a viable and useful tool for landslide risk mitigation over wide areas. Inventories of rainfall-induced landslides are critical to support investigations of where and when landslides have happened and may occur in the future, i.e. to establish reliable correlations between rainfall characteristics and landslide occurrences. In this work a parametric study has been conducted to evaluate the performance of correlation models between rainfall and landslides over the Italian territory using the "FraneItalia" database, an inventory of landslides retrieved from online Italian journalistic news. The information reported for each record of this database always include: the site of occurrence of the landslides, the date of occurrence, the source of the news. Multiple landslides occurring in the same date, within the same province or region, are inventoried together in one single record of the database, in this case also reporting the number of landslides of the event. Each record the database may also include, if the related information is available: hour of occurrence; typology, volume and material of the landslide; activity phase; effects on people, structures, infrastructures, cars or other elements. The database currently contains six complete years of data (2010-2015), including more than 4000 landslide reports, most of them triggered by rainfall. For the aim of this study, different rainfall-landslides correlation models have been tested by analysing the reported landslides, within all the 144 zones identified by the national civil protection for weather-related warnings in Italy, in relation to satellite-based precipitations estimates from the Global Precipitation

On the occurrence of fatal landslides in 2008

NASA Astrophysics Data System (ADS)

Petley, D.

2009-04-01

This paper represents the latest in an annual review of fatal landslide events worldwide, based upon the Durham Fatal Landslide Database. Landslide events were inevitably dominated by the occurrence of the 12th May Wenchuan Earthquake in Sichuan Province of China, which triggered very extensive landsliding. Whilst it will be very difficult to estimate the true impact of this event in terms of landslides, the Chinese authorities estimate that about 29,000 people were killed by landslides, with several thousand more losing their lives whilst trapped in rubble due to the inability of rescuers to pass through landslide affected areas. Considerable work is needed to understand the reasons for the intensity of the landslide processes. Elsewhere the number of fatal landslides recorded totalled 405 worldwide. These caused 3526 fatalities, giving a total for the year of about 32,526 people. To put this into context, according to the CRED EM-DAT database the recorded number of fatalities from volcanic eruptions in the period 2000 to 2008 inclusive is 221! The distribution of fatal landslides followed the familiar patterns observed in previous years, with distinct clusters in Central China, along the southern edge of the Himalayas, in the Caribbean, in Central America, western S. America, along the western edge of the Philippine Sea plate and in Indonesia, plus a scattering elsewhere. The temporal distribution shows strong seasonality, with the peak occurring during the northern hemisphere summer. Unusually however, the peak month was September (usually it is in July), and there were large numbers of landslide events right through to November. The November landslide clusters occurred in SE. Asia and in Central / S. America, reflecting very heavy rains in these regions at that time. The reasons for this are not clear at present, although may be linked to weakening La Nina conditions that have prevailed through much of the year. An analysis is made of the relationship between

Investigation of landslide potential parameters on Zonguldak-Ereğli Highway and adverse effects of landslides in the region.

PubMed

Can, Eray

2014-04-01

Landslides are natural phenomena in the same class of natural disasters as earthquakes, floods, hurricanes, erosion, and volcanic eruptions that adversely affect human lives and property. Owing to their widespread occurrence, landslides are easily visible and able to be partially understood by people witnessing them. Nevertheless, to comprehend the detail of their formation and determine their potential, it is necessary to undertake geodetic, geological, and geophysical measurements in regions prone to landslides. By analyzing these measurements, it is possible to better ascertain those regions predisposed to landslides and thus provide the means to prevent loss of life and property. The city of Zonguldak, situated in the Western Black Sea region of Turkey, has a high occurrence of landslides owing to its harsh topography with rugged and steep slopes and rainfall in almost every season. Furthermore, the diurnal temperature ranging up to 10 °C in all seasons, especially in winter, plays a crucial role in rock disintegration in this region. Other factors damage ground composition and trigger landslides, such as underground mining operations, road construction that collapses rocky hills using explosives, and excavation works in steep terrain for building construction. This study gives a detailed account of the causes and adverse effects of landslides and their parameters through examples of landslide occurrences in the region, together with the results and analyses of two periods of geodetic measurements conducted on the Zonguldak-Ereğli Highway in Ilıksu district.

Dam removal: Listening in

NASA Astrophysics Data System (ADS)

Foley, M. M.; Bellmore, J. R.; O'Connor, J. E.; Duda, J. J.; East, A. E.; Grant, G. E.; Anderson, C. W.; Bountry, J. A.; Collins, M. J.; Connolly, P. J.; Craig, L. S.; Evans, J. E.; Greene, S. L.; Magilligan, F. J.; Magirl, C. S.; Major, J. J.; Pess, G. R.; Randle, T. J.; Shafroth, P. B.; Torgersen, C. E.; Tullos, D.; Wilcox, A. C.

2017-07-01

Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings. Based on dam removals thus far, some general conclusions have emerged: (1) physical responses are typically fast, with the rate of sediment erosion largely dependent on sediment characteristics and dam-removal strategy; (2) ecological responses to dam removal differ among the affected upstream, downstream, and reservoir reaches; (3) dam removal tends to quickly reestablish connectivity, restoring the movement of material and organisms between upstream and downstream river reaches; (4) geographic context, river history, and land use significantly influence river restoration trajectories and recovery potential because they control broader physical and ecological processes and conditions; and (5) quantitative modeling capability is improving, particularly for physical and broad-scale ecological effects, and gives managers information needed to understand and predict long-term effects of dam removal on riverine ecosystems. Although these studies collectively enhance our understanding of how riverine ecosystems respond to dam removal, knowledge gaps remain because most studies have been short (< 5 years) and do not adequately represent the diversity of dam types, watershed conditions, and dam-removal methods in the U.S.

Dam removal: Listening in

USGS Publications Warehouse

Foley, Melissa M.; Bellmore, James; O'Connor, James E.; Duda, Jeff; East, Amy E.; Grant, Gordon G.; Anderson, Chauncey; Bountry, Jennifer A.; Collins, Mathias J.; Connolly, Patrick J.; Craig, Laura S.; Evans, James E.; Greene, Samantha; Magilligan, Francis J.; Magirl, Christopher S.; Major, Jon J.; Pess, George R.; Randle, Timothy J.; Shafroth, Patrick B.; Torgersen, Christian E.; Tullos, Desiree D.; Wilcox, Andrew C.

2017-01-01

Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings. Based on dam removals thus far, some general conclusions have emerged: (1) physical responses are typically fast, with the rate of sediment erosion largely dependent on sediment characteristics and dam-removal strategy; (2) ecological responses to dam removal differ among the affected upstream, downstream, and reservoir reaches; (3) dam removal tends to quickly reestablish connectivity, restoring the movement of material and organisms between upstream and downstream river reaches; (4) geographic context, river history, and land use significantly influence river restoration trajectories and recovery potential because they control broader physical and ecological processes and conditions; and (5) quantitative modeling capability is improving, particularly for physical and broad-scale ecological effects, and gives managers information needed to understand and predict long-term effects of dam removal on riverine ecosystems. Although these studies collectively enhance our understanding of how riverine ecosystems respond to dam removal, knowledge gaps remain because most studies have been short (< 5 years) and do not adequately represent the diversity of dam types, watershed conditions, and dam-removal methods in the U.S.

Disseminating Landslide Hazard Information for California Local Government

NASA Astrophysics Data System (ADS)

Wills, C. J.

2010-12-01

Since 1969, the California Geological Survey has produced numerous maps showing landslide features and delineating potential slope-stability problem areas. These maps have been provided to local governments to encourage consideration of landslide hazards in planning and development decisions. Maps produced from 1986 through 1995 under the Landslide Hazard Mapping Act were advisory only, and their use by local government was never consistent. By contrast, maps of Zones of Required Investigation for seismically induced landslides produced under the Seismic Hazard Zoning Act since 1997 come with detailed guidelines and legal requirements. A legislative act that required landslide hazards be mapped and hazard maps disseminated to local government proved ineffective in landslide hazard mitigation. A later act with requirements that the hazard zone maps be used by local government proved more effective. Planning scenarios have proven to be an effective way of transmitting scientific information about natural hazards to emergency response professionals. Numerous earthquake planning scenarios have been prepared and used as the basis for emergency response exercises. An advantage of scenarios that include loss estimates is that the effects can be put in units of measure that everyone understands, principally deaths and dollars. HAZUS software available from FEMA allows calculation of losses for earthquake scenarios, but similar methods for landslides have not been developed. As part of the USGS Multi-Hazard Demonstration Project, we have estimated the landslide losses for a major west-coast winter storm scenario by developing a system based loosely on HAZUS. Data on landslide damage in past storms has been sparse and inconsistent, but a few data sets are available. The most detailed and complete available data on landslide damage was gathered by the City of Los Angeles following the 1978 storms. We extrapolate from that data to the entire state by first generalizing a

Geomorphic response of the North Fork Stillaguamish River to the State Route 530 landslide near Oso, Washington

USGS Publications Warehouse

Anderson, Scott W.; Keith, Mackenzie K.; Magirl, Christopher S.; Wallick, J. Rose; Mastin, Mark C.; Foreman, James R.

2017-08-03

just downstream of the landslide, about 1 meter high and extending a kilometer downstream, and a 0.3-meter pulse of aggradation observed 5 kilometers downstream of the landslide. In both locations, peak aggradation and channel response occurred within about a month of the landslide, and both sites had largely recovered to pre-landslide conditions by July 2014. No substantial channel change clearly linked to the landslide was observed after July 2014 except for a modest fining of surficial gravel size distributions and continued recovery and incision of the reach just downstream of the landslide.The muted downstream response of the North Fork Stillaguamish River to the State Route 530 Landslide primarily can be attributed to the cohesive, silt- and clay-rich material that bounded most of the new channel. Although the river efficiently incised a new channel through the deposit, subsequent rates of lateral erosion were slowed by the tall, cohesive banks, limiting the total volume of sediment delivery. Once entrained, however, most landslide material was rapidly transported downstream in suspension with little geomorphic effect. Landslide material coarse enough to travel as bedload was predominantly sand and fine gravel, and sediment transport models and observations of downstream change indicated that the rate of coarse sediment delivery from the landslide did not exceed the rivers ability to transport that material. The generally muted downstream response to sediment delivery from the State Route 530 Landslide, as well as the mechanics of that delivery and response, were generally consistent with observations made following the intentional removal of constructed dams.The rate and efficiency of erosion from the landslide decreased over the period of analysis, as the new channel approached a quasi-equilibrium form. In the absence of additional hillslope activity, rates of erosion from the landslide are likely to be small compared to those over the first 18 months after

Case Histories of Landslide Impact: A Database-driven Approach

NASA Astrophysics Data System (ADS)

Klose, Martin; Damm, Bodo

2015-04-01

Fundamental understanding of landslide risk requires in-depth knowledge of how landslides have impacted society in the past (e.g., Corominas et al., 2014). A key to obtain insights into the evolution of landslide risk at single facilities of critical infrastructures are case histories of landslide impact. The purpose of such historical analyses is to inform about the site-specific interactions between landslides and land-use activity. Case histories support correlating landslide events and associated damages with multiple control variables of landslide risk, including (i) previous construction works, (ii) hazard awareness, (iii) the type of structure or its material properties, and (iv) measures of post-disaster mitigation. It is a key advantage of case histories to provide an overview of the changes in the exposure and vulnerability of infrastructures over time. Their application helps to learn more about changing patterns in risk culture and the effectiveness of repair or prevention measures (e.g., Klose et al., 2014). Case histories of landslide impact are developed on the basis of information extracted from landslide databases. The use of path diagrams and illustrated flowcharts as data modeling techniques is aimed at structuring, condensing, and visualizing complex historical data sets on landslide activity and land-use. Much of the scientific potential of case histories simply depends on the quality of available database information. Landslide databases relying on a bottom-up approach characterized by targeted local data specification are optimally suited for historical impact analyses. Combined with systematic retrieval, extraction, and integration of data from multiple sources, landslide databases constitute a valuable tool for developing case histories that enable to open a whole new window on the study of landslide impacts (e.g., Damm and Klose, 2014). The present contribution introduces such a case history for a well-known landslide site at a heavily

Deformation Monitoring and Analysis of Lsp Landslide Based on Gbinsar

NASA Astrophysics Data System (ADS)

Zhou, L.; Guo, J.; Yang, F.

2018-05-01

Monitoring and analyzing the deformation of the river landslide in city to master the deformation law of landslide, which is an important means of landslide safety assessment. In this paper, aiming at the stability of the Liu Sha Peninsula Landslide during its strengthening process after the landslide disaster. Continuous and high precision deformation monitoring of the landslide was carried out by GBInSAR technique. Meanwhile, the two-dimensional deformation time series pictures of the landslide body were retrieved by the time series analysis method. The deformation monitoring and analysis results show that the reinforcement belt on the landslide body was basically stable and the deformation of most PS points on the reinforcement belt was within 1 mm. The deformation of most areas on the landslide body was basically within 4 mm, and the deformation presented obvious nonlinear changes. GBInSAR technique can quickly and effectively obtain the entire deformation information of the river landslide and the evolution process of deformation.

Dam removal: Listening in

Treesearch

M. M. Foley; J. R. Bellmore; J. E. O' Connor; J. J. Duda; A. E. East; G. E. Grant; C. W. Anderson; J. A. Bountry; M. J. Collins; P. J. Connolly; L. S. Craig; J. E. Evans; S. L. Greene; F. J. Magilligan; C. S. Magirl; J. J. Major; G. R. Pess; T. J. Randle; P. B. Shafroth; C. E. Torgersen; D. Tullos; A. C. Wilcox

2017-01-01

Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings....

Establishment of Stereo Multi-sensor Network for Giant Landslide Monitoring and its Deploy in Xishan landslide, Sichuan, China.

NASA Astrophysics Data System (ADS)

Liu, C.; Lu, P.; WU, H.

2015-12-01

Landslide is one of the most destructive natural disasters, which severely affects human lives as well as the safety of personal properties and public infrastructures. Monitoring and predicting landslide movements can keep an adequate safety level for human beings in those situations. This paper indicated a newly developed Stereo Multi-sensor Landslide Monitoring Network (SMSLMN) based on a uniform temporal geo-reference. Actually, early in 2003, SAMOA (Surveillance et Auscultation des Mouvements de Terrain Alpins, French) project was put forwarded as a plan for landslide movements monitoring. However, SAMOA project did not establish a stereo observation network to fully cover the surface and internal part of landslide. SMSLMN integrated various sensors, including space-borne, airborne, in-situ and underground sensors, which can quantitatively monitor the slide-body and obtain portent information of movement in high frequency with high resolution. The whole network has been deployed at the Xishan landslide, Sichuan, P.R.China. According to various characteristic of stereo monitoring sensors, observation capabilities indicators for different sensors were proposed in order to obtain the optimal sensors combination groups and observation strategy. Meanwhile, adaptive networking and reliable data communication methods were developed to apply intelligent observation and sensor data transmission. Some key technologies, such as signal amplification and intelligence extraction technology, data access frequency adaptive adjustment technology, different sensor synchronization control technology were developed to overcome the problems in complex observation environment. The collaboratively observation data have been transferred to the remote data center where is thousands miles away from the giant landslide spot. These data were introduced into the landslide stability analysis model, and some primary conclusion will be achieved at the end of paper.

Rainfall characteristics for shallow landsliding in Seattle, Washington, USA

USGS Publications Warehouse

Godt, J.W.; Baum, R.L.; Chleborad, A.F.

2006-01-01

Shallow landsliding in the Seattle, Washington, area, has caused the occasional loss of human life and millions of dollars in damage to property. The effective management of the hazzard requires an understanding of the rainfall conditions that result in landslides. We present an empirical approach to quantify the antecedent moisture conditions and rainstorm intensity and duration that have triggered shallow landsliding using 25 years of hourly rainfull data and a complementary record of landslide occurrence. Our approach combines a simple water balance to estimate the antecedent moisture conditions of hillslope materials and a rainfall intensity-duration threshold to identify periods when shallow landsliding can be expected. The water balance is calibrated with field-monitoring data and combined with the rainfall intensity-duration threshold using a decision tree. Results are cast in terms of a hypothetical landslide warning system. Two widespread landslide events are correctly identified by the warning scheme; however, it is less accurate for more isolated landsliding. Copyright ?? 2005 John Wiley & Sons, Ltd.

Landslide inventory for the Little North Santiam River Basin, Oregon

USGS Publications Warehouse

Sobieszczyk, Steven

2010-01-01

This geodatabase is an inventory of existing landslides in the Little North Santiam River Basin, Oregon (2009). Each landslide feature shown has been classified according to a number of specific characteristics identified at the time recorded in the GIS database. The classification scheme was developed by the Oregon Department of Geology and Mineral Industries (Burns and Madin, 2009). Several significant landslide characteristics recorded in the database are portrayed with symbology on this map. The specific characteristics shown for each landslide are the activity of landsliding, landslide features, deep or shallow failure, type of landslide movement, and confidence of landslide interpretation. These landslide characteristics are determined primarily on the basis of geomorphic features, or landforms, observed for each landslide. This work was completed as part of the Master's thesis "Turbidity Monitoring and LiDAR Imagery Indicate Landslides are Primary Source of Suspended-Sediment Load in the Little North Santiam River Basin, Oregon, Winter 2009-2010" by Steven Sobieszczyk, Portland State University and U.S. Geological Survey. Data layers in this geodatabase include: landslide deposit boundaries (Deposits); field-verfied location imagery (Photos); head scarp or scarp flanks (Scarp_Flanks); and secondary scarp features (Scarps).The geodatabase template was developed by the Oregon Department of Geology and Mineral Industries (Burns and Madin, 2009).

Examination of economical methods for repairing highway landslides.

DOT National Transportation Integrated Search

2005-04-01

The Kentucky Transportation Cabinet spends millions of dollars each year in the repairs of highway landslides. In previous research, an inventory of highway landslides showed that about 1440 landslides of various sizes exist on major roadways maintai...

Rainfall-Triggered Landslides Bury Sri Lankan Villages

NASA Technical Reports Server (NTRS)

Kirschbaum, Dalia; Stanley, Thomas

2016-01-01

On the afternoon of May 17th, 2016, a major landslide event caused at least 92 deaths, with 109 still missing*. The site was rated highly susceptible to landslides in a new global landslide susceptibility map. GPM precipitation data suggest that both antecedent and current rainfall as well as complex topography played a role in the slope failures.

Coprates Chasma Landslide

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site]

Coprates Chasma comprises the central portion of the Valles Marineris canyon system complex. This image of the southern wall of Coprates Chasma contains a landslide deposit with dunes over portions of slide. Landslides have very characteristic morphologies on Earth, which they also display on Mars. These morphologies include a distinctive escarpment at the uppermost part of the landslide--called a head scarp (seen at the bottom of this image), a down-dropped block of material below that escarpment that dropped almost vertically, and a deposit of debris that moved away from the escarpment at high speed. In this example, the wall rock displayed in the upper part of the cliff contains spurs and chutes created by differing amounts of erosion. The actual landslide deposit is delineated by its fan-shape and lobate margins. The dunes subsequently marched upon the landslide deposit.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a

A methodological approach to characterise Landslide Periods based on historical series of rainfall and landslide damage

NASA Astrophysics Data System (ADS)

Petrucci, O.; Pasqua, A. A.

2009-10-01

Landslide Periods (LPs) are defined as periods, shorter than a hydrological year, during which one or more landslide damage events occur in one or more sectors of a study area. In this work, we present a methodological approach, based on the comparative analysis of historical series of landslide damage and daily rainfall data, aiming to characterise the main types of LPs affecting selected areas. Cumulative rainfall preceding landslide activation is assessed for short (1, 2, 3, and 5 days), medium (7, 10, and 30 days) and long (60, 90, and 180 days) durations, and their Return Periods (RPs) are assessed and ranked into three classes (Class 1: RP=5-10 years; Class 2: RP=11-15; Class 3: RP>15 years). To assess landslide damage, the Simplified Damage Index (SDI) is introduced. This represents classified landslide losses and is obtained by multiplying the value of the damaged element and the percentage of damage affecting it. The comparison of the RP of rainfall and the SDI allows us to indentify the different types of LPs that affected the study area in the past and that could affect it again in the future. The results of this activity can be used for practical purposes to define scenarios and strategies for risk management, to suggest priorities in policy towards disaster mitigation and preparedness and to predispose defensive measures and civil protection plans ranked according to the types of LPs that must be managed. We present an application, performed for a 39-year series of rainfall/landslide damage data and concerning a study area located in NE Calabria (Italy); in this case study, we identify four main types of LPs, which are ranked according to damage severity.

Debris-flow initiation from large, slow-moving landslides

USGS Publications Warehouse

Reid, M.E.; Brien, D.L.; LaHusen, R.G.; Roering, J.J.; de la Fuente, J.; Ellen, S.D.; ,

2003-01-01

In some mountainous terrain, debris flows preferentially initiate from the toes and margins of larger, deeper, slower-moving landslides. During the wet winter of 1997, we began real-time monitoring of the large, active Cleveland Corral landslide complex in California, USA. When the main slide is actively moving, small, shallow, first-time slides on the toe and margins mobilize into debris flows and travel down adjacent gullies. We monitored the acceleration of one such failure; changes in velocity provided precursory indications of rapid failure. Three factors appear to aid the initiation of debris flows at this site: 1) locally steepened ground created by dynamic landslide movement, 2) elevated pore-water pressures and abundant soil moisture, and 3) locally cracked and dilated materials. This association between debris flows and large landslides can be widespread in some terrain. Detailed photographic mapping in two watersheds of northwestern California illustrates that the areal density of debris-flow source landsliding is about 3 to 7 times greater in steep geomorphically fresher landslide deposits than in steep ground outside landslide deposits. ?? 2003 Millpress.

Dam failure analysis for the Lago El Guineo Dam, Orocovis, Puerto Rico

USGS Publications Warehouse

Gómez-Fragoso, Julieta; Heriberto Torres-Sierra,

2016-08-09

The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed hydrologic and hydraulic analyses to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago El Guineo Dam. The Lago El Guineo Dam is within the headwaters of the Río Grande de Manatí and impounds a drainage area of about 4.25 square kilometers.The hydrologic assessment was designed to determine the outflow hydrographs and peak discharges for Lago El Guineo and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation event, (2) a 24-hour probable maximum precipitation event, and (3) a 24-hour, 100-year recurrence rainfall event. The hydraulic study simulated a dam failure of Lago El Guineo Dam using flood hydrographs generated from the hydrologic study. The simulated dam failure generated a hydrograph that was routed downstream from Lago El Guineo Dam through the lower reaches of the Río Toro Negro and the Río Grande de Manatí to determine water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” conditions. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC–HMS) and Hydrologic Engineering Center’s River Analysis System (HEC–RAS) computer programs, developed by the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively. The flow routing in the hydraulic analyses was completed using the unsteady flow module available in the HEC–RAS model.Above the Lago El Guineo Dam, the simulated inflow peak discharges from HEC–HMS resulted in about 550 and 414 cubic meters per second for the 6- and 24-hour probable maximum precipitation events, respectively. The 24-hour, 100-year recurrence storm simulation resulted in a peak discharge of about 216 cubic meters per second. For the hydrologic analysis, no dam failure conditions are

Quick clay and landslides of clayey soils.

PubMed

Khaldoun, Asmae; Moller, Peder; Fall, Abdoulaye; Wegdam, Gerard; De Leeuw, Bert; Méheust, Yves; Otto Fossum, Jon; Bonn, Daniel

2009-10-30

We study the rheology of quick clay, an unstable soil responsible for many landslides. We show that above a critical stress the material starts flowing abruptly with a very large viscosity decrease caused by the flow. This leads to avalanche behavior that accounts for the instability of quick clay soils. Reproducing landslides on a small scale in the laboratory shows that an additional factor that determines the violence of the slides is the inhomogeneity of the flow. We propose a simple yield stress model capable of reproducing the laboratory landslide data, allowing us to relate landslides to the measured rheology.

Quick Clay and Landslides of Clayey Soils

NASA Astrophysics Data System (ADS)

Khaldoun, Asmae; Moller, Peder; Fall, Abdoulaye; Wegdam, Gerard; de Leeuw, Bert; Méheust, Yves; Otto Fossum, Jon; Bonn, Daniel

2009-10-01

We study the rheology of quick clay, an unstable soil responsible for many landslides. We show that above a critical stress the material starts flowing abruptly with a very large viscosity decrease caused by the flow. This leads to avalanche behavior that accounts for the instability of quick clay soils. Reproducing landslides on a small scale in the laboratory shows that an additional factor that determines the violence of the slides is the inhomogeneity of the flow. We propose a simple yield stress model capable of reproducing the laboratory landslide data, allowing us to relate landslides to the measured rheology.

Landslide monitoring in the Atlantic Highlands area, New Jersey

USGS Publications Warehouse

Reilly, Pamela A.; Ashland, Francis X.; Fiore, Alex R.

2017-08-25

Shallow and deep-seated landslides have occurred episodically on the steep coastal bluffs of the Atlantic Highlands area (Boroughs of Atlantic Highlands and Highlands) in New Jersey. The oldest documented deep-seated landslide occurred in April 1782 and significantly changed the morphology of the bluff. However, recent landslides have been mostly shallow in nature and have occurred during large storms with exceptionally heavy rainfall. These shallow landslides have resulted in considerable damage to residential property and local infrastructure and threatened human safety.The recent shallow landslides in the area (locations modified from New Jersey Department of Environmental Protection) consist primarily of slumps and flows of earth and debris within areas of historical landslides or on slopes modified by human activities. Such landslides are typically triggered by increases in shallow soil moisture and pore-water pressure caused by sustained and intense rainfall associated with spring nor’easters and late summer–fall tropical cyclones. However, the critical relation between rainfall, soil-moisture conditions, and landslide movement has not been fully defined. The U.S. Geological Survey is currently monitoring hillslopes within the Atlantic Highlands area to better understand the hydrologic and meteorological conditions associated with shallow landslide initiation.

Precursory Seismicity Associated With Landslides, Including the 2017 Tsunamigenic Landslide in the Karrat Fjord, Greenland

NASA Astrophysics Data System (ADS)

Caplan-Auerbach, J.

2017-12-01

On the evening of June 17 2017, a massive landslide fell from the wall of the Karrat Fjord, Greenland, generating a tsunami that caused the deaths of four residents in the nearby village of Nuugaatsiaq. The slide took place at a bluff 30 km from the village, where a broadband seismometer (DK.NUUG) is permanently deployed. The landslide generated a seismic signal initially interpreted as a magnitude 4.1 earthquake, as well as a tsunami that initially reached heights exceeding 100 m. Prior to the large seismic signal, however, station NUUG detected a series of several dozen small pulses, most of which were highly similar in time series. The pulses occur more frequently with time, until they effectively merge with the seismic signal of the landslide. The pulses were not detected on any other seismic stations, so their source locations cannot be calculated, but particle motions suggest that they were coming from an azimuth of 30o, consistent with the location of the landslide relative to Nuugaatsiaq. This particular sequence, in which small, repeating earthquakes occur with increasing frequency prior to a landslide, has been observed in at least four other locations: (1) on Mt. Baker (Washington) during an ice avalanche in 1976 (Weaver and Malone, 1979), (2) repeatedly on Iliamna volcano (Alaska) in association with glacial avalanches (Caplan-Auerbach and Huggel, 2007), (3) on Mt. Stellar (Alaska) prior to a 2006 rockfall (Huggel et al., 2010), and (4) as part of the Kausu landslide (Japan), in 2015 (Yamada et al., 2016). In all cases the precursory events exhibited waveform similarity, indicative of a repeating point of failure. These events represent stick-slip behavior at the landslide base. The precursory sequences last several hours, suggesting that detection of these events could provide a means of warning prior to failure. This may be useful in areas where instabilities or incipient failures are evident.

Object-based Landslide Mapping: Examples, Challenges and Opportunities

NASA Astrophysics Data System (ADS)

Hölbling, Daniel; Eisank, Clemens; Friedl, Barbara; Chang, Kang-Tsung; Tsai, Tsai-Tsung; Birkefeldt Møller Pedersen, Gro; Betts, Harley; Cigna, Francesca; Chiang, Shou-Hao; Aubrey Robson, Benjamin; Bianchini, Silvia; Füreder, Petra; Albrecht, Florian; Spiekermann, Raphael; Weinke, Elisabeth; Blaschke, Thomas; Phillips, Chris

2016-04-01

Over the last decade, object-based image analysis (OBIA) has been increasingly used for mapping landslides that occur after triggering events such as heavy rainfall. The increasing availability and quality of Earth Observation (EO) data in terms of temporal, spatial and spectral resolution allows for comprehensive mapping of landslides at multiple scales. Most often very high resolution (VHR) or high resolution (HR) optical satellite images are used in combination with a digital elevation model (DEM) and its products such as slope and curvature. Semi-automated object-based mapping makes use of various characteristics of image objects that are derived through segmentation. OBIA enables numerous spectral, spatial, contextual and textural image object properties to be applied during an analysis. This is especially useful when mapping complex natural features such as landslides and constitutes an advantage over pixel-based image analysis. However, several drawbacks in the process of object-based landslide mapping have not been overcome yet. The developed classification routines are often rather complex and limited regarding their transferability across areas and sensors. There is still more research needed to further improve present approaches and to fully exploit the capabilities of OBIA for landslide mapping. In this study several examples of object-based landslide mapping from various geographical regions with different characteristics are presented. Examples from the Austrian and Italian Alps are shown, whereby one challenge lies in the detection of small-scale landslides on steep slopes while preventing the classification of false positives with similar spectral properties (construction areas, utilized land, etc.). Further examples feature landslides mapped in Iceland, where the differentiation of landslides from other landscape-altering processes in a highly dynamic volcanic landscape poses a very distinct challenge, and in Norway, which is exposed to multiple

Surveying perceptions of landslide risk management in Norway

NASA Astrophysics Data System (ADS)

Chiu, Jessica Ka Yi; Eidsvig, Unni

2016-04-01

Enhanced precipitation due to climate change leads to increase in both frequency and intensity of landslides in Norway. A proactive approach to risk management is therefore required to significantly reduce the losses associated with landslides. Opinions and perceptions from practitioners on the performance of landslide risk management can provide insights on areas for improvement in the landslide risk management strategies in Norway. The Risk Management Index (RMI), proposed by Cardona et al. (2004), is a well-established method to measure perceptions of disaster management of selected actors holistically. The RMI is measured based on opinion questionnaires to technical staff, decision-makers, and stakeholders involved in all stages of risk reduction strategies. It is a composite index that considers a wide variety of strategies to manage risks, including structural and non-structural measures, acceptance strategies, disaster management, and risk transfer. The RMI method was modified to be implemented in landslide hazards and to fit with Norwegian conditions. An opinion survey was conducted in autumn 2015 to measure perceptions of landslide risk management in Norway. Perceptions were surveyed for two time periods: 2015 and 2050, and are based on national, county, and municipality levels. Based on the survey results, performance of landslide risk management at any administrative levels in Norway is perceived to improve from `significant' in 2015 to `significant' to `outstanding' in 2050. Knowledge and technology, climate, risk perceptions, and anthropogenic activities are mostly considered by respondents for their 2050 perceptions. Several aspects of landslide risk management in Norway can be improved. For example, landslide hazard evaluation and mapping should be prioritised in Norway. Upgrading, retrofitting, and reconstruction of assets may also be included in the landslide risk reduction strategies. In addition, there should be more focus on inter

Landslides Mapped from LIDAR Imagery, Kitsap County, Washington

USGS Publications Warehouse

McKenna, Jonathan P.; Lidke, David J.; Coe, Jeffrey A.

2008-01-01

Landslides are a recurring problem on hillslopes throughout the Puget Lowland, Washington, but can be difficult to identify in the densely forested terrain. However, digital terrain models of the bare-earth surface derived from LIght Detection And Ranging (LIDAR) data express topographic details sufficiently well to identify landslides. Landslides and escarpments were mapped using LIDAR imagery and field checked (when permissible and accessible) throughout Kitsap County. We relied almost entirely on derivatives of LIDAR data for our mapping, including topographic-contour, slope, and hill-shaded relief maps. Each mapped landslide was assigned a level of 'high' or 'moderate' confidence based on the LIDAR characteristics and on field observations. A total of 231 landslides were identified representing 0.8 percent of the land area of Kitsap County. Shallow debris topples along the coastal bluffs and large (>10,000 m2) landslide complexes are the most common types of landslides. The smallest deposit mapped covers an area of 252 m2, while the largest covers 0.5 km2. Previous mapping efforts that relied solely on field and photogrammetric methods identified only 57 percent of the landslides mapped by LIDAR (61 percent high confidence and 39 percent moderate confidence), although nine landslides previously identified were not mapped during this study. The remaining 43 percent identified using LIDAR have 13 percent high confidence and 87 percent moderate confidence. Coastal areas are especially susceptible to landsliding; 67 percent of the landslide area that we mapped lies within 500 meters of the present coastline. The remaining 33 percent are located along drainages farther inland. The LIDAR data we used for mapping have some limitations including (1) rounding of the interface area between low slope surfaces and vertical faces (that is, along the edges of steep escarpments) which results in scarps being mapped too far headward (one or two meters), (2) incorrect laser

Methods for landslide susceptibility modelling in Lower Austria

NASA Astrophysics Data System (ADS)

Bell, Rainer; Petschko, Helene; Glade, Thomas; Leopold, Philip; Heiss, Gerhard; Proske, Herwig; Granica, Klaus; Schweigl, Joachim; Pomaroli, Gilbert

2010-05-01

Landslide susceptibility modelling and implementation of the resulting maps is still a challenge for geoscientists, spatial and infrastructure planners. Particularly on a regional scale landslide processes and their dynamics are poorly understood. Furthermore, the availability of appropriate spatial data in high resolution is often a limiting factor for modelling high quality landslide susceptibility maps for large study areas. However, these maps form an important basis for preventive spatial planning measures. Thus, new methods have to be developed, especially focussing on the implementation of final maps into spatial planning processes. The main objective of the project "MoNOE" (Method development for landslide susceptibility modelling in Lower Austria) is to design a method for landslide susceptibility modelling for a large study area (about 10.200 km²) and to produce landslide susceptibility maps which are finally implemented in the spatial planning strategies of the Federal state of Lower Austria. The project focuses primarily on the landslide types fall and slide. To enable susceptibility modelling, landslide inventories for the respective landslide types must be compiled and relevant data has to be gathered, prepared and homogenized. Based on this data new methods must be developed to tackle the needs of the spatial planning strategies. Considerable efforts will also be spent on the validation of the resulting maps for each landslide type. A great challenge will be the combination of the susceptibility maps for slides and falls in just one single susceptibility map (which is requested by the government) and the definition of the final visualisation. Since numerous landslides have been favoured or even triggered by human impact, the human influence on landslides will also have to be investigated. Furthermore possibilities to integrate respective findings in regional susceptibility modelling will be explored. According to these objectives the project is

Rainfall thresholds for possible landslide occurrence in Italy

NASA Astrophysics Data System (ADS)

Peruccacci, Silvia; Brunetti, Maria Teresa; Gariano, Stefano Luigi; Melillo, Massimo; Rossi, Mauro; Guzzetti, Fausto

2017-08-01

The large physiographic variability and the abundance of landslide and rainfall data make Italy an ideal site to investigate variations in the rainfall conditions that can result in rainfall-induced landslides. We used landslide information obtained from multiple sources and rainfall data captured by 2228 rain gauges to build a catalogue of 2309 rainfall events with - mostly shallow - landslides in Italy between January 1996 and February 2014. For each rainfall event with landslides, we reconstructed the rainfall history that presumably caused the slope failure, and we determined the corresponding rainfall duration D (in hours) and cumulated event rainfall E (in mm). Adopting a power law threshold model, we determined cumulated event rainfall-rainfall duration (ED) thresholds, at 5% exceedance probability, and their uncertainty. We defined a new national threshold for Italy, and 26 regional thresholds for environmental subdivisions based on topography, lithology, land-use, land cover, climate, and meteorology, and we used the thresholds to study the variations of the rainfall conditions that can result in landslides in different environments, in Italy. We found that the national and the environmental thresholds cover a small part of the possible DE domain. The finding supports the use of empirical rainfall thresholds for landslide forecasting in Italy, but poses an empirical limitation to the possibility of defining thresholds for small geographical areas. We observed differences between some of the thresholds. With increasing mean annual precipitation (MAP), the thresholds become higher and steeper, indicating that more rainfall is needed to trigger landslides where the MAP is high than where it is low. This suggests that the landscape adjusts to the regional meteorological conditions. We also observed that the thresholds are higher for stronger rocks, and that forested areas require more rainfall than agricultural areas to initiate landslides. Finally, we

Probabilistic clustering of rainfall condition for landslide triggering

NASA Astrophysics Data System (ADS)

Rossi, Mauro; Luciani, Silvia; Cesare Mondini, Alessandro; Kirschbaum, Dalia; Valigi, Daniela; Guzzetti, Fausto

2013-04-01

Landslides are widespread natural and man made phenomena. They are triggered by earthquakes, rapid snow melting, human activities, but mostly by typhoons and intense or prolonged rainfall precipitations. In Italy mostly they are triggered by intense precipitation. The prediction of landslide triggered by rainfall precipitations over large areas is commonly based on the exploitation of empirical models. Empirical landslide rainfall thresholds are used to identify rainfall conditions for the possible landslide initiation. It's common practice to define rainfall thresholds by assuming a power law lower boundary in the rainfall intensity-duration or cumulative rainfall-duration space above which landslide can occur. The boundary is defined considering rainfall conditions associated to landslide phenomena using heuristic approaches, and doesn't consider rainfall events not causing landslides. Here we present a new fully automatic method to identify the probability of landslide occurrence associated to rainfall conditions characterized by measures of intensity or cumulative rainfall and rainfall duration. The method splits the rainfall events of the past in two groups: a group of events causing landslides and its complementary, then estimate their probabilistic distributions. Next, the probabilistic membership of the new event to one of the two clusters is estimated. The method doesn't assume a priori any threshold model, but simple exploits the real empirical distribution of rainfall events. The approach was applied in the Umbria region, Central Italy, where a catalogue of landslide timing, were obtained through the search of chronicles, blogs and other source of information in the period 2002-2012. The approach was tested using rain gauge measures and satellite rainfall estimates (NASA TRMM-v6), allowing in both cases the identification of the rainfall condition triggering landslides in the region. Compared to the other existing threshold definition methods, the prosed

Landslide inventory maps: New tools for an old problem

NASA Astrophysics Data System (ADS)

Guzzetti, Fausto; Mondini, Alessandro Cesare; Cardinali, Mauro; Fiorucci, Federica; Santangelo, Michele; Chang, Kang-Tsung

2012-04-01

Landslides are present in all continents, and play an important role in the evolution of landscapes. They also represent a serious hazard in many areas of the world. Despite their importance, we estimate that landslide maps cover less than 1% of the slopes in the landmasses, and systematic information on the type, abundance, and distribution of landslides is lacking. Preparing landslide maps is important to document the extent of landslide phenomena in a region, to investigate the distribution, types, pattern, recurrence and statistics of slope failures, to determine landslide susceptibility, hazard, vulnerability and risk, and to study the evolution of landscapes dominated by mass-wasting processes. Conventional methods for the production of landslide maps rely chiefly on the visual interpretation of stereoscopic aerial photography, aided by field surveys. These methods are time consuming and resource intensive. New and emerging techniques based on satellite, airborne, and terrestrial remote sensing technologies, promise to facilitate the production of landslide maps, reducing the time and resources required for their compilation and systematic update. In this work, we first outline the principles for landslide mapping, and we review the conventional methods for the preparation of landslide maps, including geomorphological, event, seasonal, and multi-temporal inventories. Next, we examine recent and new technologies for landslide mapping, considering (i) the exploitation of very-high resolution digital elevation models to analyze surface morphology, (ii) the visual interpretation and semi-automatic analysis of different types of satellite images, including panchromatic, multispectral, and synthetic aperture radar images, and (iii) tools that facilitate landslide field mapping. Next, we discuss the advantages and the limitations of the new remote sensing data and technology for the production of geomorphological, event, seasonal, and multi-temporal inventory maps

New Insights on co-seismic landslide clustering

NASA Astrophysics Data System (ADS)

Meunier, Patrick; Marc, Odin; Hovius, Niels

2015-04-01

Earthquake-triggered landslides tend to cluster along topographic crests while rainfall-induced landslides should occur downslope preferentially, where pore pressure induced by groundwater flows is the highest [1]. Past studies on landslide clustering are all based on the analysis of complete dataset or subdataset of landslides associated with a given event (seismic or climatic) as a whole. In this work, we document the spatial and temporal variations of the landslide position (on hillslopes) within the epicentral area of the 1994 Northridge, the 1999 Chichi, the 2004 Niigata, the 2008 Iwate and the 2008 Wenchuan earthquakes. We show that crest clustering is not systematic, non uniform in space and exhibit patterns that vary a lot from one case to another. These patterns are not easy to interpret as they don't seem to be controlled by a single governing parameter but result from a complex interaction between local (hillslope length and gradient, lithology) and seismic (distance to source, slope aspect, radiation pattern, coseismic uplift) parameters. [1] Meunier, P., Hovius, N., & Haines, J. A. (2008). Topographic site effects and the location of earthquake induced landslides. Earth and Planetary Science Letters, 275(3), 221-232

Landslide mobility and hazards: implications of the 2014 Oso disaster

USGS Publications Warehouse

Iverson, Richard M.; George, David L.; Allstadt, Kate E.; Reid, Mark E.; Collins, Brian D.; Vallance, James W.; Schilling, Steve P.; Godt, Jonathan W.; Cannon, Charles; Magirl, Christopher S.; Baum, Rex L.; Coe, Jeffrey A.; Schulz, William; Bower, J. Brent

2015-01-01

Landslides reflect landscape instability that evolves over meteorological and geological timescales, and they also pose threats to people, property, and the environment. The severity of these threats depends largely on landslide speed and travel distance, which are collectively described as landslide “mobility”. To investigate causes and effects of mobility, we focus on a disastrous landslide that occurred on 22 March 2014 near Oso, Washington, USA, following a long period of abnormally wet weather. The landslide's impacts were severe because its mobility exceeded that of prior historical landslides at the site, and also exceeded that of comparable landslides elsewhere. The ∼8×106 m3 landslide originated on a gently sloping (<20°) riverside bluff only 180 m high, yet it traveled across the entire ∼1 km breadth of the adjacent floodplain and spread laterally a similar distance. Seismological evidence indicates that high-speed, flowing motion of the landslide began after about 50 s of preliminary slope movement, and observational evidence supports the hypothesis that the high mobility of the landslide resulted from liquefaction of water-saturated sediment at its base. Numerical simulation of the event using a newly developed model indicates that liquefaction and high mobility can be attributed to compression- and/or shear-induced sediment contraction that was strongly dependent on initial conditions. An alternative numerical simulation indicates that the landslide would have been far less mobile if its initial porosity and water content had been only slightly lower. Sensitive dependence of landslide mobility on initial conditions has broad implications for assessment of landslide hazards.

Landslide mobility and hazards: implications of the 2014 Oso disaster

NASA Astrophysics Data System (ADS)

Iverson, R. M.; George, D. L.; Allstadt, K.; Reid, M. E.; Collins, B. D.; Vallance, J. W.; Schilling, S. P.; Godt, J. W.; Cannon, C. M.; Magirl, C. S.; Baum, R. L.; Coe, J. A.; Schulz, W. H.; Bower, J. B.

2015-02-01

Landslides reflect landscape instability that evolves over meteorological and geological timescales, and they also pose threats to people, property, and the environment. The severity of these threats depends largely on landslide speed and travel distance, which are collectively described as landslide "mobility". To investigate causes and effects of mobility, we focus on a disastrous landslide that occurred on 22 March 2014 near Oso, Washington, USA, following a long period of abnormally wet weather. The landslide's impacts were severe because its mobility exceeded that of prior historical landslides at the site, and also exceeded that of comparable landslides elsewhere. The ∼ 8 ×106 m3 landslide originated on a gently sloping (<20°) riverside bluff only 180 m high, yet it traveled across the entire ∼1 km breadth of the adjacent floodplain and spread laterally a similar distance. Seismological evidence indicates that high-speed, flowing motion of the landslide began after about 50 s of preliminary slope movement, and observational evidence supports the hypothesis that the high mobility of the landslide resulted from liquefaction of water-saturated sediment at its base. Numerical simulation of the event using a newly developed model indicates that liquefaction and high mobility can be attributed to compression- and/or shear-induced sediment contraction that was strongly dependent on initial conditions. An alternative numerical simulation indicates that the landslide would have been far less mobile if its initial porosity and water content had been only slightly lower. Sensitive dependence of landslide mobility on initial conditions has broad implications for assessment of landslide hazards.

Global Scale Analysis of Martian Landslide Mobility and Paleoenvironmental Clues

NASA Astrophysics Data System (ADS)

Crosta, Giovanni Battista; De Blasio, Fabio Vittorio; Frattini, Paolo

2018-04-01

The mobility of landslides on Mars is studied based on a database of 3,118 events. To establish the volume of the landslides for the whole data set based on the deposit area, a new volume-area relationship based on a representative data set of 222 landslides is used. By plotting the H/L ratio between fall height H and runout L versus volume, the landslide mobility is analyzed and compared with existing empirical relationships for Martian and terrestrial landslides. By analyzing the mobility in terms of normalized residuals, that is, the relative deviation of the H/L ratio from the data set best-fit line, mobility is found to depend on both the landslide location on Mars and the landslide typology. This allows us to identify four different types of high-mobility (hypermobile) landslides. Three classes of high-mobility landslides are associated respectively to meteoroid impact, the Olympus Mons aureoles, and landslides with Toreva-block failure style, and their mobility can be explained by the peculiar flow mechanics. The fourth class includes landslides associated with isolated craters, those in the regions wetted by the putative Oceanus Borealis, and the ones at high latitudes. We suggest that the common factor behind all the hypermobile landslides of this fourth kind is the presence of ice. This is confirmed by our data showing that landslides increase in mobility with latitude. The latitudinal trend mirrors the distribution of ice as detected by radar, neutron probes, and the presence of glacial and layered ejecta morphologies. Because the overall landslide distribution supports the presence of ice-lubricated conditions, two ice lubrication models are presented showing how ice melting within or underneath the landslides could enhance mobility. By proper analysis in terms of apparent friction residuals, we find that the mobility of landslides in Valles Marineris with the largest landslide concentration is lower than average. We explain this circumstance partly

Comparison of Structurally Controlled Landslide Hazard Simulation to the Co-seismic Landslides Caused by the M 7.2 2013 Bohol Earthquake.

NASA Astrophysics Data System (ADS)

Galang, J. A. M. B.; Eco, R. C.; Lagmay, A. M. A.

2014-12-01

The M_w 7.2 October 15, 2013 Bohol earthquake is one of the more destructive earthquake to hit the Philippines in the 21st century. The epicenter was located in Sagbayan municipality, central Bohol and was generated by a previously unmapped reverse fault called the "Inabanga Fault". The earthquake resulted in 209 fatalities and over 57 million USD worth of damages. The earthquake generated co-seismic landslides most of which were related to fault structures. Unlike rainfall induced landslides, the trigger for co-seismic landslides happen without warning. Preparations for this type of landslides rely heavily on the identification of fracture-related slope instability. To mitigate the impacts of co-seismic landslide hazards, morpho-structural orientations of discontinuity sets were mapped using remote sensing techniques with the aid of a Digital Terrain Model (DTM) obtained in 2012. The DTM used is an IFSAR derived image with a 5-meter pixel resolution and approximately 0.5 meter vertical accuracy. Coltop 3D software was then used to identify similar structures including measurement of their dip and dip directions. The chosen discontinuity sets were then keyed into Matterocking software to identify potential rock slide zones due to planar or wedged discontinuities. After identifying the structurally-controlled unstable slopes, the rock mass propagation extent of the possible rock slides was simulated using Conefall. Separately, a manually derived landslide inventory has been performed using post-earthquake satellite images and LIDAR. The results were compared to the landslide inventory which identified at least 873 landslides. Out of the 873 landslides identified through the inventory, 786 or 90% intersect the simulated structural-controlled landslide hazard areas of Bohol. The results show the potential of this method to identify co-seismic landslide hazard areas for disaster mitigation. Along with computer methods to simulate shallow landslides, and debris flow

Multiscale/multiresolution landslides susceptibility mapping

NASA Astrophysics Data System (ADS)

Grozavu, Adrian; Cătălin Stanga, Iulian; Valeriu Patriche, Cristian; Toader Juravle, Doru

2014-05-01

Within the European strategies, landslides are considered an important threatening that requires detailed studies to identify areas where these processes could occur in the future and to design scientific and technical plans for landslide risk mitigation. In this idea, assessing and mapping the landslide susceptibility is an important preliminary step. Generally, landslide susceptibility at small scale (for large regions) can be assessed through qualitative approach (expert judgements), based on a few variables, while studies at medium and large scale requires quantitative approach (e.g. multivariate statistics), a larger set of variables and, necessarily, the landslide inventory. Obviously, the results vary more or less from a scale to another, depending on the available input data, but also on the applied methodology. Since it is almost impossible to have a complete landslide inventory on large regions (e.g. at continental level), it is very important to verify the compatibility and the validity of results obtained at different scales, identifying the differences and fixing the inherent errors. This paper aims at assessing and mapping the landslide susceptibility at regional level through a multiscale-multiresolution approach from small scale and low resolution to large scale and high resolution of data and results, comparing the compatibility of results. While the first ones could be used for studies at european and national level, the later ones allows results validation, including through fields surveys. The test area, namely the Barlad Plateau (more than 9000 sq.km) is located in Eastern Romania, covering a region where both the natural environment and the human factor create a causal context that favor these processes. The landslide predictors were initially derived from various databases available at pan-european level and progressively completed and/or enhanced together with scale and the resolution: the topography (from SRTM at 90 meters to digital

Landslide!

NASA Image and Video Library

2017-05-12

This image from NASA Mars Reconnaissance Orbiter shows a fresh well-preserved landslide scarp and rocky deposit off the edge of a streamlined mesa in Simud Valles, a giant outflow channel carved by ancient floods. A stereo anaglyph is available at https://photojournal.jpl.nasa.gov/catalog/PIA21633

Dam failure analysis for the Lago de Matrullas Dam, Orocovis, Puerto Rico

USGS Publications Warehouse

Torres-Sierra, Heriberto; Gómez-Fragoso, Julieta

2015-01-01

Results from the simulated dam failure of the Lago de Matrullas Dam using the HEC–RAS model for the 6- and 24-hour PMP events showed peak discharges at the dam of 3,149.33 and 3,604.70 m3/s, respectively. Dam failure during the 100-year-recurrence, 24-hour rainfall event resulted in a peak discharge of 2,103.12 m3/s directly downstream from the dam. Dam failure under sunny day conditions produced a peak discharge of 1,695.91 m3/s at the dam assuming the antecedent lake level was at the morning-glory spillway invert elevation. Flood-inundation maps prepared as part of the study depict the flood extent and provide valuable information for preparing an Emergency Action Plan. Results of the failure analysis indicate that a failure of the Lago de Matrullas Dam could cause flooding to many of the inhabited areas along stream banks from the Lago de Matrullas Dam to the mouth of the Río Grande de Manatí. Among the areas most affected are the low-lying regions in the vicinity of the towns of Ciales, Manatí, and Barceloneta. The delineation of the flood boundaries near the town of Barceloneta considered the effects of a levee constructed during 2000 at Barceloneta in the flood plain of the Río Grande de Manatí to provide protection against flooding to the near-by low-lying populated areas. The results showed overtopping can be expected in the aforementioned levee during 6- and 24-hour probable-maximum-precipitation dam failure scenarios. No overtopping of the levee was simulated, however, during dam failure scenarios under the 100-year recurrence, 24-hour rainfall event or sunny day conditions.

Landslide susceptibility mapping for a landslide-prone area (Findikli, NE of Turkey) by likelihood-frequency ratio and weighted linear combination models

NASA Astrophysics Data System (ADS)

Akgun, Aykut; Dag, Serhat; Bulut, Fikri

2008-05-01

Landslides are very common natural problems in the Black Sea Region of Turkey due to the steep topography, improper use of land cover and adverse climatic conditions for landslides. In the western part of region, many studies have been carried out especially in the last decade for landslide susceptibility mapping using different evaluation methods such as deterministic approach, landslide distribution, qualitative, statistical and distribution-free analyses. The purpose of this study is to produce landslide susceptibility maps of a landslide-prone area (Findikli district, Rize) located at the eastern part of the Black Sea Region of Turkey by likelihood frequency ratio (LRM) model and weighted linear combination (WLC) model and to compare the results obtained. For this purpose, landslide inventory map of the area were prepared for the years of 1983 and 1995 by detailed field surveys and aerial-photography studies. Slope angle, slope aspect, lithology, distance from drainage lines, distance from roads and the land-cover of the study area are considered as the landslide-conditioning parameters. The differences between the susceptibility maps derived by the LRM and the WLC models are relatively minor when broad-based classifications are taken into account. However, the WLC map showed more details but the other map produced by LRM model produced weak results. The reason for this result is considered to be the fact that the majority of pixels in the LRM map have high values than the WLC-derived susceptibility map. In order to validate the two susceptibility maps, both of them were compared with the landslide inventory map. Although the landslides do not exist in the very high susceptibility class of the both maps, 79% of the landslides fall into the high and very high susceptibility zones of the WLC map while this is 49% for the LRM map. This shows that the WLC model exhibited higher performance than the LRM model.

Landslide risk assessment

USGS Publications Warehouse

Lessing, P.; Messina, C.P.; Fonner, R.F.

1983-01-01

Landslide risk can be assessed by evaluating geological conditions associated with past events. A sample of 2,4 16 slides from urban areas in West Virginia, each with 12 associated geological factors, has been analyzed using SAS computer methods. In addition, selected data have been normalized to account for areal distribution of rock formations, soil series, and slope percents. Final calculations yield landslide risk assessments of 1.50=high risk. The simplicity of the method provides for a rapid, initial assessment prior to financial investment. However, it does not replace on-site investigations, nor excuse poor construction. ?? 1983 Springer-Verlag New York Inc.

Modelling of Rainfall Induced Landslides in Puerto Rico

NASA Astrophysics Data System (ADS)

Lepore, C.; Arnone, E.; Sivandran, G.; Noto, L. V.; Bras, R. L.

2010-12-01

We performed an island-wide determination of static landslide susceptibility and hazard assessment as well as dynamic modeling of rainfall-induced shallow landslides in a particular hydrologic basin. Based on statistical analysis of past landslides, we determined that reliable prediction of the susceptibility to landslides is strongly dependent on the resolution of the digital elevation model (DEM) employed and the reliability of the rainfall data. A distributed hydrology model, Triangulated Irregular Network (TIN)-based Real-time Integrated Basin Simulator with VEGetation Generator for Interactive Evolution (tRIBS-VEGGIE), tRIBS-VEGGIE, has been implemented for the first time in a humid tropical environment like Puerto Rico and validated against in-situ measurements. A slope-failure module has been added to tRIBS-VEGGIE’s framework, after analyzing several failure criterions to identify the most suitable for our application; the module is used to predict the location and timing of landsliding events. The Mameyes basin, located in the Luquillo Experimental Forest in Puerto Rico, was selected for modeling based on the availability of soil, vegetation, topographical, meteorological and historic landslide data. Application of the model yields a temporal and spatial distribution of predicted rainfall-induced landslides.

Hydroclimatic conditions preceding the March 2014 Oso landslide

USGS Publications Warehouse

Henn, Brian; Cao, Qian; Lettenmaier, Dennis P.; Magirl, Christopher S.; Mass, Clifford; Bower, J. Brent; St. Laurent, Michael; Mao, Yixin; Perica, Sanja

2015-01-01

The 22 March 2014 Oso landslide was one of the deadliest in U.S. history, resulting in 43 fatalities and the destruction of more than 40 structures. We examine synoptic conditions, precipitation records and soil moisture reconstructions in the days, months, and years preceding the landslide. Atmospheric reanalysis shows a period of enhanced moisture transport to the Pacific Northwest beginning on 11 February 2014. The 21- to 42-day periods prior to the landslide had anomalously high precipitation; we estimate that 300-400 mm of precipitation fell at Oso in the 21 days prior to the landslide. Relative only to historical periods ending on 22 March, the return periods of these precipitation accumulations are large (25-88 years). However, relative to the largest accumulations from any time of the year (annual maxima), return periods are more modest (2-6 years). In addition to the 21-42 days prior to the landslide, there is a secondary maximum in the precipitation return periods for the 4 years preceding the landslide. Reconstructed soil moisture was anomalously high prior to the landslide, with a return period that exceeded 40 years about a week before the event.

Comparison of the Structurally Controlled Landslides Numerical Model Results to the M 7.2 2013 Bohol Earthquake Co-seismic Landslides

NASA Astrophysics Data System (ADS)

Macario Galang, Jan Albert; Narod Eco, Rodrigo; Mahar Francisco Lagmay, Alfredo

2015-04-01

The M 7.2 October 15, 2013 Bohol earthquake is the most destructive earthquake to hit the Philippines since 2012. The epicenter was located in Sagbayan municipality, central Bohol and was generated by a previously unmapped reverse fault called the "Inabanga Fault". Its name, taken after the barangay (village) where the fault is best exposed and was first seen. The earthquake resulted in 209 fatalities and over 57 billion USD worth of damages. The earthquake generated co-seismic landslides most of which were related to fault structures. Unlike rainfall induced landslides, the trigger for co-seismic landslides happen without warning. Preparedness against this type of landslide therefore, relies heavily on the identification of fracture-related unstable slopes. To mitigate the impacts of co-seismic landslide hazards, morpho-structural orientations or discontinuity sets were mapped in the field with the aid of a 2012 IFSAR Digital Terrain Model (DTM) with 5-meter pixel resolution and < 0.5 meter vertical accuracy. Coltop 3D software was then used to identify similar structures including measurement of their dip and dip directions. The chosen discontinuity sets were then keyed into Matterocking software to identify potential rock slide zones due to planar or wedged discontinuities. After identifying the structurally-controlled unstable slopes, the rock mass propagation extent of the possible rock slides was simulated using Conefall. The results were compared to a post-earthquake landslide inventory of 456 landslides. Out the total number of landslides identified from post-earthquake high-resolution imagery, 366 or 80% intersect the structural-controlled hazard areas of Bohol. The results show the potential of this method to identify co-seismic landslide hazard areas for disaster mitigation. Along with computer methods to simulate shallow landslides, and debris flow paths, located structurally-controlled unstable zones can be used to mark unsafe areas for settlement. The

Assessment of landslide hazards in Kaluanui and Maakua gulches, Oahu, Hawaii, following the 9 May 1999 Sacred Falls landslide

USGS Publications Warehouse

Jibson, R.W.; Baum, R.L.

1999-01-01

One of the injured hikers later died of injuries received in the landslide. Governor Ben Cayetano of Hawaii ordered that the park be closed due to concern about continuing landslide hazard near the falls. Subsequently, Bill Meyer, District Chief for the U.S. Geological Survey (USGS) Water Resources Division in Honolulu contacted Tim Johns, Chair of the Board of Land and Natural Resources of the Hawaii Department of Land and Natural Resources (DLNR) and offered assistance in assessing slope stability in the park. Mr. Johns accepted the offer, and two landslide specialists from the USGS Geologic Hazards Team in Golden Colorado were sent to the site. On Friday, 14 May 1999, we visited the Sacred Falls landslide site with Glenn Bauer, Ed Sakoda, and Gary Moniz of DLNR. The ground investigation involved inspecting the impact area, estimating the volume of the deposit, and gathering data to help reconstruct the event. On Monday, 17 May 1999, we conducted an aerial reconnaissance of Kaluanui Gulch (Sacred Falls State Park) and Maakua Gulch in a commercial helicopter provided by DLNR. We inspected the source and path of movement of the Sacred Falls landslide of 9 May and reconnoitered the full length of both valleys to get an overview of ongoing landslide hazards there. This report gives our observations and conclusions about the Sacred Falls landslide, broadly assesses the ongoing hazard in the Kaluanui and Maakua Gulches, and suggests methods for more detailed assessment of landslide hazards here and along other trails in state parks on Oahu. Observations and conclusions in this report are based on a very brief investigation and thus are preliminary in nature.

Landslide Susceptibility Statistical Methods: A Critical and Systematic Literature Review

NASA Astrophysics Data System (ADS)

Mihir, Monika; Malamud, Bruce; Rossi, Mauro; Reichenbach, Paola; Ardizzone, Francesca

2014-05-01

Landslide susceptibility assessment, the subject of this systematic review, is aimed at understanding the spatial probability of slope failures under a set of geomorphological and environmental conditions. It is estimated that about 375 landslides that occur globally each year are fatal, with around 4600 people killed per year. Past studies have brought out the increasing cost of landslide damages which primarily can be attributed to human occupation and increased human activities in the vulnerable environments. Many scientists, to evaluate and reduce landslide risk, have made an effort to efficiently map landslide susceptibility using different statistical methods. In this paper, we do a critical and systematic landslide susceptibility literature review, in terms of the different statistical methods used. For each of a broad set of studies reviewed we note: (i) study geography region and areal extent, (ii) landslide types, (iii) inventory type and temporal period covered, (iv) mapping technique (v) thematic variables used (vi) statistical models, (vii) assessment of model skill, (viii) uncertainty assessment methods, (ix) validation methods. We then pulled out broad trends within our review of landslide susceptibility, particularly regarding the statistical methods. We found that the most common statistical methods used in the study of landslide susceptibility include logistic regression, artificial neural network, discriminant analysis and weight of evidence. Although most of the studies we reviewed assessed the model skill, very few assessed model uncertainty. In terms of geographic extent, the largest number of landslide susceptibility zonations were in Turkey, Korea, Spain, Italy and Malaysia. However, there are also many landslides and fatalities in other localities, particularly India, China, Philippines, Nepal and Indonesia, Guatemala, and Pakistan, where there are much fewer landslide susceptibility studies available in the peer-review literature. This

Automatic Detection of Landslides at Stromboli Volcano

NASA Astrophysics Data System (ADS)

Giudicepietro, F.; Esposito, A. M.; D'Auria, L.; Peluso, R.; Martini, M.

2011-12-01

In this work we present an automatic system for the landslide detection at Stromboli volcano that has proved to be effective both during the 2007 effusive eruption and in the recent (2 August 2011) volcanic activity. The study of the landslides at Stromboli is important because they could be considered short-term precursors of effusive eruptions, as seen during the 2007 eruption, and in addition they allow to improve the monitoring of the gravitational instabilities of the Sciara del Fuoco flank. The proposed system uses a two-class MLP (Multi Layer Perceptron) neural network in order to discriminate the landslides from other seismic signals usually recorded at Stromboli, such as explosion-quakes and volcanic tremor. To train and test the network we used a dataset of 537 signals, including 267 landslides and 270 other events (130 explosion-quakes and 140 tremor signals). The net performance is of 98.7%, if averaged over different net configurations, and of 99.5% for the best net performance. Based on the neural network response, the automatic system calculates a Landslide Percentage Index (LPI) defined on the number of signals identified as landslides by the net on a given temporal interval in order to recognize anomalies in the landslide rate. This system was sensitive to the signals produced by the flow of lava front during a recent mild effusive episode on the "La Sciara del Fuoco" slope.

Shallow-landslide hazard map of Seattle, Washington

USGS Publications Warehouse

Harp, Edwin L.; Michael, John A.; Laprade, William T.

2006-01-01

Landslides, particularly debris flows, have long been a significant cause of damage and destruction to people and property in the Puget Sound region. Following the years of 1996 and 1997, the Federal Emergency Management Agency (FEMA) designated Seattle as a 'Project Impact' city with the goal of encouraging the city to become more disaster resistant to the effects of landslides and other natural hazards. A major recommendation of the Project Impact council was that the city and the U.S. Geological Survey (USGS) collaborate to produce a landslide hazard map of the city. An exceptional data set archived by the city, containing more than 100 years of landslide data from severe storm events, allowed comparison of actual landslide locations with those predicted by slope-stability modeling. We used an infinite-slope analysis, which models slope segments as rigid friction blocks, to estimate the susceptibility of slopes to shallow landslides which often mobilize into debris flows, water-laden slurries that can form from shallow failures of soil and weathered bedrock, and can travel at high velocities down steep slopes. Data used for analysis consisted of a digital slope map derived from recent Light Detection and Ranging (LIDAR) imagery of Seattle, recent digital geologic mapping, and shear-strength test data for the geologic units in the surrounding area. The combination of these data layers within a Geographic Information System (GIS) platform allowed the preparation of a shallow landslide hazard map for the entire city of Seattle.

TRIGRS Application for landslide susceptibility mapping

NASA Astrophysics Data System (ADS)

Sugiarti, K.; Sukristiyanti, S.

2018-02-01

Research on landslide susceptibility has been carried out using several different methods. TRIGRS is a modeling program for landslide susceptibility by considering pore water pressure changes due to infiltration of rainfall. This paper aims to present a current state-of-the-art science on the development and application of TRIGRS. Some limitations of TRIGRS, some developments of it to improve its modeling capability, and some examples of the applications of some versions of it to model the effect of rainfall variation on landslide susceptibility are reviewed and discussed.

The landslide hazard in the San Francisco Bay region

USGS Publications Warehouse

Brabb, E.E.

1977-01-01

Development in hilly or mountainous terrain has resulted in much landslide damage. Areas susceptible to landsliding can be recognized. Practices for minimizing landslides are presented. ?? 1977 D. Reidel Publishing Company.

Non-Susceptible Landslide Areas in Italy and in the Mediterranean Region

NASA Astrophysics Data System (ADS)

Alvioli, Massimiliano; Ardizzone, Francesca; Guzzetti, Fausto; Marchesini, Ivan; Rossi, Mauro

2014-05-01

Landslide susceptibility is the likelihood of a landslide occurring in a given area. Over the past three decades, researchers, and planning and environmental organisations have worked to assess landslide susceptibility at different geographical scales, and to produce maps portraying landslide susceptibility zonation. Little effort was made to determine where landslides are not expected, where susceptibility is null, or negligible. This is surprising because planners and decision makers are also interesting in knowing where landslides are not foreseen, or cannot occur in an area. We propose a method for the definition of non-susceptible landslide areas, at the synoptic scale. We applied the method in Italy and to the territory surrounding the Mediterranean Sea and we produced two synoptic-scale maps showing areas where landslides are not expected in Italy and in the Mediterranean area. To construct the method we used digital terrain elevation and landslide information. The digital terrain consisted in the 3-arc-second SRTM DEM, the landslide information was obtained for 13 areas in Italy where landslide inventory maps were available to us. We tested three different models to determine the non-susceptible landslide areas, including a linear model (LR), a quantile linear model (QLR), and a quantile non-linear model (QNL). Model performances have been evaluated using independent landslide information represented by the Italian Landslide Inventory (Inventario Fenomeni Franosi in Italia - IFFI). Best results were obtained using the QNL model. The corresponding zonation of non- susceptible landslide areas was intersected in a GIS with geographical census data for Italy. The results show that the 57.5% of the population of Italy (in 2001) was located in areas where landslide susceptibility was expected to be null or negligible, while the remaining 42.5% in areas where some landslide susceptibility was significant or not negligible. We applied the QNL model to the

GIS-based landslide hazard evaluation at the regional scale: some critical points in the permanent displacement approach for seismically-induced landslide maps

NASA Astrophysics Data System (ADS)

Vessia, Giovanna; Parise, Mario

2013-04-01

local practitioners. Seismically-induced landslide hazard maps have been drawn using the aforementioned three expressions. The preliminary results show Quaternary deposits (including alluvium deposits, slope wash, and terrace deposits) as the lithologies most affected by permanent displacement. Moreover, Towsley and Modelo formations, that are stiffer than the previous rock units, and consist mostly of shales, siltstones and subordinate sandstones, show high hazard value where the slopes increase. The relevant role of local slope in permanent displacement extent is evident where lithologies are characterized by both cohesive and frictional resistance components. Finally, a comparison among the maps produced by using the three expressions for permanent displacements is discussed. References Ambraseys N.N. and Menu J.M. (1988) Earthquake-induced ground displacements. Earthquake Engineering and Structural Dynamics, 16: 985-1006. Harp E.L. and Jibson R.W. (1995) Inventory of landslides triggered by the 1994 Northridge, California earthquake. US Geol. Surv. Open-File Rep. 95-213 17 pp. Jibson R. (2007) Regression models for estimating coseismic landslide displacement. Engineering Geology, 91: 209-218. Luzi L. and Pergalani F. (2000) A correlation between slope failures and accelerometric parameters: the 26 September 1997 earthquake (Umbria-Marche, Italy). Soil Dynamics and Earthquake Engineering, 20: 301-313. Newmark N.M. (1965) Effects of earthquakes on dams and embankments. Geotechnique 965, 15(2): 139-160. Parise M. and Jibson R.W. (2000) A seismic landslide susceptibility rating of geologic units based on analysis of characteristics of landslides triggered by the 17 January, 1994 Northridge, California earthquake. Engineering Geology, 58: 251-270. Romeo R. (2000) Seismically induced landslide displacements: a predictive model. Engineering Geology, 58: 337-351.

Object-based landslide detection in different geographic regions

NASA Astrophysics Data System (ADS)

Friedl, Barbara; Hölbling, Daniel; Eisank, Clemens; Blaschke, Thomas

2015-04-01

Landslides occur in almost all mountainous regions of the world and rank among the most severe natural hazards. In the last decade - according to the world disaster report 2014 published by the International Federation of Red Cross and Red Crescent Societies (IRFC) - more than 9.000 people were killed by mass movements, more than 3.2 million people were affected and the total amount of disaster estimated damage accounts to more than 1.700 million US dollars. The application of remote sensing data for mapping landslides can contribute to post-disaster reconstruction or hazard mitigation, either by providing rapid information about the spatial distribution and location of landslides in the aftermath of triggering events or by creating and updating landslide inventories. This is especially valid for remote and inaccessible areas, where information on landslides is often lacking. However, reliable methods are needed for extracting timely and relevant information about landslides from remote sensing data. In recent years, novel methods such as object-based image analysis (OBIA) have been successfully employed for semi-automated landslide mapping. Several studies revealed that OBIA frequently outperforms pixel-based approaches, as a range of image object properties (spectral, spatial, morphometric, contextual) can be exploited during the analysis. However, object-based methods are often tailored to specific study areas, and thus, the transferability to regions with different geological settings, is often limited. The present case study evaluates the transferability and applicability of an OBIA approach for landslide detection in two distinct regions, i.e. the island of Taiwan and Austria. In Taiwan, sub-areas in the Baichi catchment in the North and in the Huaguoshan catchment in the southern-central part of the island are selected; in Austria, landslide-affected sites in the Upper Salzach catchment in the federal state of Salzburg are investigated. For both regions

A Tool for Modelling the Probability of Landslides Impacting Road Networks

NASA Astrophysics Data System (ADS)

Taylor, Faith E.; Santangelo, Michele; Marchesini, Ivan; Malamud, Bruce D.; Guzzetti, Fausto

2014-05-01

Triggers such as earthquakes or heavy rainfall can result in hundreds to thousands of landslides occurring across a region within a short space of time. These landslides can in turn result in blockages across the road network, impacting how people move about a region. Here, we show the development and application of a semi-stochastic model to simulate how landslides intersect with road networks during a triggered landslide event. This was performed by creating 'synthetic' triggered landslide inventory maps and overlaying these with a road network map to identify where road blockages occur. Our landslide-road model has been applied to two regions: (i) the Collazzone basin (79 km2) in Central Italy where 422 landslides were triggered by rapid snowmelt in January 1997, (ii) the Oat Mountain quadrangle (155 km2) in California, USA, where 1,350 landslides were triggered by the Northridge Earthquake (M = 6.7) in January 1994. For both regions, detailed landslide inventory maps for the triggered events were available, in addition to maps of landslide susceptibility and road networks of primary, secondary and tertiary roads. To create 'synthetic' landslide inventory maps, landslide areas (AL) were randomly selected from a three-parameter inverse gamma probability density function, consisting of a power law decay of about -2.4 for medium and large values of AL and an exponential rollover for small values of AL. The number of landslide areas selected was based on the observed density of landslides (number of landslides km-2) in the triggered event inventories. Landslide shapes were approximated as ellipses, where the ratio of the major and minor axes varies with AL. Landslides were then dropped over the region semi-stochastically, conditioned by a landslide susceptibility map, resulting in a synthetic landslide inventory map. The originally available landslide susceptibility maps did not take into account susceptibility changes in the immediate vicinity of roads, therefore

Methods of Measuring and Mapping of Landslide Areas

NASA Astrophysics Data System (ADS)

Skrzypczak, Izabela; Kokoszka, Wanda; Kogut, Janusz; Oleniacz, Grzegorz

2017-12-01

The problem of attracting new investment areas and the inability of current zoning areas, allows us to understand why it is impossible to completely rule out building on landslide areas. Therefore, it becomes important issue of monitoring areas at risk of landslides. Only through appropriate monitoring and proper development of measurements resulting as maps of areas at risk of landslides enables us to estimate the risk and the relevant economic calculation for the realization of the anticipated investment in such areas. The results of monitoring of the surface and in-depth of the landslides are supplemented with constant observation of precipitation. The previous analyses and monitoring of landslides show that some of them are continuously active. GPS measurements, especially with laser scanning provide a unique activity data acquired on the surface of each individual landslide. The development of high resolution numerical models of terrain and the creation of differential models based on subsequent measurements, informs us about the size of deformation, both in units of distance (displacements) and volume. The compatibility of the data with information from in-depth monitoring allows the generation of a very reliable in-depth model of landslide, and as a result proper calculation of the volume of colluvium. Programs presented in the article are a very effective tool to generate in-depth model of landslide. In Poland, the steps taken under the SOPO project i.e. the monitoring and description of landslides are absolutely necessary for social and economic reasons and they may have a significant impact on the economy and finances of individual municipalities and also a whole country economy.

Landslides Zonation Hazard: relation between geological structures and landslides occurrence in hilly tropical regions of Brazil.

PubMed

Cerri, Rodrigo I; Reis, Fábio A G V; Gramani, Marcelo F; Giordano, Lucilia C; Zaine, José Eduardo

2017-01-01

This paper presents a new approach of landslides zonation hazard studies, based on an integrated study of structural data along with geomorphological and external factors, in a hilly regions of Brazil, covered by a tropical humid rain-forest, called Serra do Mar. The Serra do Mar consists of a hilly region along the east coast of Brazil, with high slopes and many geological structures in a gneiss - migmatitic terrain. In contrast to traditional approaches, this method proposes that structural data (foliation, fractures and bedding planes) and its relation with the slope geometry, is important to be consider in the landslide zonation hazard, along with declivity, relative relief, soil and rock properties, land use and vegetation cover and hydrogeological and climate factors. Results show that slopes with high hazard have the same dip direction of geological structures. Landslide zonation hazard using structural data contributes to a better understanding of how these structures, preserved in tropical residual soils, influence on slope stability and generates landslides.

Landslide susceptibility map: from research to application

NASA Astrophysics Data System (ADS)

Fiorucci, Federica; Reichenbach, Paola; Ardizzone, Francesca; Rossi, Mauro; Felicioni, Giulia; Antonini, Guendalina

2014-05-01

Susceptibility map is an important and essential tool in environmental planning, to evaluate landslide hazard and risk and for a correct and responsible management of the territory. Landslide susceptibility is the likelihood of a landslide occurring in an area on the basis of local terrain conditions. Can be expressed as the probability that any given region will be affected by landslides, i.e. an estimate of "where" landslides are likely to occur. In this work we present two examples of landslide susceptibility map prepared for the Umbria Region and for the Perugia Municipality. These two maps were realized following official request from the Regional and Municipal government to the Research Institute for the Hydrogeological Protection (CNR-IRPI). The susceptibility map prepared for the Umbria Region represents the development of previous agreements focused to prepare: i) a landslide inventory map that was included in the Urban Territorial Planning (PUT) and ii) a series of maps for the Regional Plan for Multi-risk Prevention. The activities carried out for the Umbria Region were focused to define and apply methods and techniques for landslide susceptibility zonation. Susceptibility maps were prepared exploiting a multivariate statistical model (linear discriminant analysis) for the five Civil Protection Alert Zones defined in the regional territory. The five resulting maps were tested and validated using the spatial distribution of recent landslide events that occurred in the region. The susceptibility map for the Perugia Municipality was prepared to be integrated as one of the cartographic product in the Municipal development plan (PRG - Piano Regolatore Generale) as required by the existing legislation. At strategic level, one of the main objectives of the PRG, is to establish a framework of knowledge and legal aspects for the management of geo-hydrological risk. At national level most of the susceptibility maps prepared for the PRG, were and still are obtained

Distant, delayed and ancient earthquake-induced landslides

NASA Astrophysics Data System (ADS)

Havenith, Hans-Balder; Torgoev, Almaz; Braun, Anika; Schlögel, Romy; Micu, Mihai

2016-04-01

On the basis of a new classification of seismically induced landslides we outline particular effects related to the delayed and distant triggering of landslides. Those cannot be predicted by state-of-the-art methods. First, for about a dozen events the 'predicted' extension of the affected area is clearly underestimated. The most problematic cases are those for which far-distant triggering of landslides had been reported, such as for the 1988 Saguenay earthquake. In Central Asia reports for such cases are known for areas marked by a thick cover of loess. One possible contributing effect could be a low-frequency resonance of the thick soils induced by distant earthquakes, especially those in the Pamir - Hindu Kush seismic region. Such deep focal and high magnitude (>>7) earthquakes are also found in Europe, first of all in the Vrancea region (Romania). For this area and others in Central Asia we computed landslide event sizes related to scenario earthquakes with M>7.5. The second particular and challenging type of triggering is the one delayed with respect to the main earthquake event: case histories have been reported for the Racha earthquake in 1991 when several larger landslides only started moving 2 or 3 days after the main shock. Similar observations were also made after other earthquake events in the U.S., such as after the 1906 San Francisco, the 1949 Tacoma, the 1959 Hebgen Lake and the 1983 Bora Peak earthquakes. Here, we will present a series of detailed examples of (partly monitored) mass movements in Central Asia that mainly developed after earthquakes, some even several weeks after the main shock: e.g. the Tektonik and Kainama landslides triggered in 1992 and 2004, respectively. We believe that the development of the massive failures is a consequence of the opening of tension cracks during the seismic shaking and their filling up with water during precipitations that followed the earthquakes. The third particular aspect analysed here is the use of large

Prediction of earthquake-triggered landslide event sizes

NASA Astrophysics Data System (ADS)

Braun, Anika; Havenith, Hans-Balder; Schlögel, Romy

2016-04-01

Seismically induced landslides are a major environmental effect of earthquakes, which may significantly contribute to related losses. Moreover, in paleoseismology landslide event sizes are an important proxy for the estimation of the intensity and magnitude of past earthquakes and thus allowing us to improve seismic hazard assessment over longer terms. Not only earthquake intensity, but also factors such as the fault characteristics, topography, climatic conditions and the geological environment have a major impact on the intensity and spatial distribution of earthquake induced landslides. We present here a review of factors contributing to earthquake triggered slope failures based on an "event-by-event" classification approach. The objective of this analysis is to enable the short-term prediction of earthquake triggered landslide event sizes in terms of numbers and size of the affected area right after an earthquake event occurred. Five main factors, 'Intensity', 'Fault', 'Topographic energy', 'Climatic conditions' and 'Surface geology' were used to establish a relationship to the number and spatial extend of landslides triggered by an earthquake. The relative weight of these factors was extracted from published data for numerous past earthquakes; topographic inputs were checked in Google Earth and through geographic information systems. Based on well-documented recent earthquakes (e.g. Haiti 2010, Wenchuan 2008) and on older events for which reliable extensive information was available (e.g. Northridge 1994, Loma Prieta 1989, Guatemala 1976, Peru 1970) the combination and relative weight of the factors was calibrated. The calibrated factor combination was then applied to more than 20 earthquake events for which landslide distribution characteristics could be cross-checked. One of our main findings is that the 'Fault' factor, which is based on characteristics of the fault, the surface rupture and its location with respect to mountain areas, has the most important

Downstream Channel Change and Bed-material Transport along the North Fork Stillaguamish River Following the March 22, 2014 SR530 Landslide, Northwestern Washington, USA

NASA Astrophysics Data System (ADS)

Keith, M. K.; Anderson, S. W.; Magirl, C. S.

2015-12-01

The March 22, 2014, catastrophic landslide near Oso, Washington, rapidly emplaced approximately 8 million m3 of slide material onto the valley floor, blocking the North Fork Stillaguamish River. Overtopping of the landslide dam and subsequent channel incision through the deposit mobilized large volumes of the glacial outwash, till, and lacustrine (silts and clays) sediment. The abundant sediment introduced to the gravel-bed channel prompted concerns of downstream aggradation and elevated hazards from seasonal flooding and channel migration. Our assessment of downstream aggradation potential and channel change was primarily based on 1) comparison of pre-slide to post-slide field-based and remote-sensing observations, 2) measurements of bedload transport, and 3) modeling of bedload transport for eight flow scenarios between 25% of the 2-year flow and the 100-year flow at several sites along the lower 65-km alluvial portion of the river. Although measurements of pre-slide grain-size distributions were highly variable from year to year, comparison of those counts to 2014 post-slide measurements show a general fining of channel and bar surface material. Between 2014 and 2015, we observed coarsening at some bars, most notably for sediment smaller than 4 mm. From aerial photograph inspection, the shape, size, and distribution of gravel and sand bars between the landslide and the mouth of the North Fork Stillaguamish River appears to have been relatively unchanged between 2013 and 2015. Post-slide bedload transport capacity rates were calculated using Parker, Wilcock and Crowe, and two forms of Recking equations. Transport capacities for the narrow and confined channel where it has incised through the landslide are much greater compared with the low gradient and wide floodplain segments downstream. Nevertheless, because of fine grain sizes within the landslide debris, most of the sediment has been transported through the downstream channel, resulting in minimal aggradation.

Assessments on landslide susceptibility in the Tseng-wen reservoir watershed, Taiwan

NASA Astrophysics Data System (ADS)

Chen, Yu-Chin; Chen, Yung-Chau; Chen, Wen-Fu

2014-05-01

Typhoon Morakot under the strong influence of southwestern monsoon wind struck Taiwan on 8 August 2009, and dumped record-breaking rains in southern Taiwan. It triggered enormous landslides in mountains and severe flooding in low-lying areas. In addition, it destroyed or damaged houses, agricultural fields, roads, bridges, and other infrastructure facilities, causing massive economic loss and, more tragically, human casualties. In order to evaluate landslide hazard and risk assessment, it is important to understand the potential sites of landslide and their spatial distribution. Multi-temporal satellite images and geo-spatial data are used to build landslide susceptibility map for the post-disaster in the Tseng-wen reservoir watershed in this research. Elevation, slope, aspect, NDVI (normalized differential vegetation index), relief, roughness, distance to river, and distance to road are the considered factors for estimating landslide susceptibility. Maximum hourly rainfall and total rainfall, accompanied with typhoon event, are selected as the trigger factors of landslide events. Logistic regression analysis is adopted as the statistical method to model landslide susceptibility. The assessed susceptibility is represented in 4 levels which are high, high-intermediate, intermediate, and low level, respectively. Landslide spatial distribution can be depicted as a landslide susceptibility map with respect to each considered influence factors for a specified susceptible level. The landslide areas are about 358 ha and 1,485 ha before and after typhoon Morakot. The new landslide area, induced by typhoon Morakot, is as almost 4 times as the landslide area before typhoon Morakot. In addition, there is about 44.56% landslide area elevation ranging from 500m to 1000m and about 57.22% average slope ranging from 30° to 45° of landslide area. Furthermore, the devastating landslides were happened at those sites close to rivers, exposed area, and area with big land cover change

Study of rainfall-induced landslide: a review

NASA Astrophysics Data System (ADS)

Tohari, A.

2018-02-01

Rainfall-induced landslides pose a substantial risk to people and infrastructure. For this reason, there have been numerous studies to understand the landslide mechanism. Most of them were performed on the numerical analysis and laboratory experiment. This paper presents a review of existing research on field hydrological condition of soil slopes leading to the initiation of rainfall-induced landslide. Existing methods to study field hydrological response of slopes are first reviewed, emphasizing their limitations and suitability of application. The typical hydrological response profiles in the slope are then discussed. Subsequently, some significant findings on hydrological condition leading to rainfall-induced landslides are summarized and discussed. Finally, several research topics are recommended for future study.

Alluvium-Buttressed Landslides: Conceptual Model and Examples from California

NASA Astrophysics Data System (ADS)

Johnson, P. L.; Cotton, W. R., Sr.; Shires, P. O.

2016-12-01

Large, deep-seated landslides typically occur in hillside settings without any natural buttressing, and many of these landslides have relatively low factors of safety (FS), the ratio of driving to resisting forces. However, where deep-seated landslides failed millennia ago into valleys that subsequently experienced alluvial aggradation, a natural buttress of alluvium may be deposited over the landslide toe, increasing the FS of these landslides. The eustatic model for alluvial buttressing of Quaternary landslides involves failure of slopes during sea level low stand at or near the late Pleistocene last glacial maximum (LGM, approximately 20 ka). Following LGM, mean sea level rose by over 120m to its present elevation. This rise in base level resulted in deposition of alluvial sediment in coastal valleys that had been v-shaped and downcutting prior to and during LGM. These valleys now have broad, low gradient floors formed by alluvial sediment, and the thick alluvial strata filling these valleys cover the toes of late Pleistocene landslides. In this study, three examples of large, deep-seated Pleistocene landslides that are buttressed by alluvium are presented. The McCracken Hill Landslide in Orange County and the Potrero Canyon Landslide Complex in Monterey County are located approximately 1.5 and 6 km, respectively, from the modern Pacific shore and closely fit the eustatic model of alluvial buttressing. At Knights Valley, in the upper Russian River watershed of eastern Sonoma County, a deep-seated alluvium-buttressed landslide is located approximately 65 km from the modern shore (measured along the Russian River and its tributary stream). The alluvium in Knights Valley may have ponded due to late Quaternary tectonic uplift of hills west of the valley. Streams that cross these hills are incised into bedrock downstream from Knights Valley and approaching the Russian River. Thus, the Knights Valley example (of an alluvium-buttressed landslide) demonstrates a rare

Climate-induced landslide reactivation at the edge of the Most Basin (Czech Republic) - progress towards better landslide prediction

NASA Astrophysics Data System (ADS)

Burda, J.; Hartvich, F.; Valenta, J.; Smítka, V.; Rybář, J.

2013-02-01

The catastrophic landslide at Eisenberg in North Bohemia was reactivated during January 2011. This study integrates a range of geoscientific evidence in order to constrain the spatial and temporal development of this reactivation. It has investigated long-term geodetic measurements to assess the morphological development of the site over the last two decades. There is evidence to suggest that, over this period, the site had been subjected to progressive deformation caused by the collapse of an old mine gallery. However, climatic data show that the reactivation itself was triggered by a dramatic rise in the water table induced by rapid snowmelt during a period of winter warming. Furthermore, geomorphological mapping has been used to characterise the morphology of the reactivated landslide and geophysical profiling has been used to analyse its internal structure. The results show that fissures are continuing to develop above the reactivated landslide scarp while highly saturated stiff-fissured claystones provide an incipient slide plane. The application of laser scanning has shown minimal evidence for ongoing landslide activity. It is, however, clear that future landslide events will occur here due to the favourable lithological, structural, and geotechnical conditions. Finally, we propose that future landslide activity at the site may be predicted by the height of water table as this defines theoretical pore pressure at the depth of the shear plane.

The potential of geoelectrics for landslide forecasting

NASA Astrophysics Data System (ADS)

Niesner, E.; Weidinger, J. T.

2009-04-01

In the last years both authors of this article had been involved into geophysical and geological investigations of potential landslide areas. In one case, fortunately to the researchers but not for the people living in this area, the investigations started three years in advance of an actual landslide. Therefore interesting measurements are now available in the fore field of an actual slide event with a volume of approximately 3.5 million cubic meter. Mainly geoelectric, seismic and geologic data had been gathered. On some profiles also repeat measurements had been done to detect changes in the subsurface, prior to the landslide. These data showed, verified by the later on landslide event, already changes in the subsurface long before the actual movement on the surface could be detected. Also some continuous geoelectric monitoring had been done during a period of ten days about four month before the initialization of the event. In this special case, the area of the Gschliefgraben in Upper Austria, especially the changes in the water saturation of the potential landslide area showed a high impact on the subsurface resistivity distribution. Geoelectric measurements are ideally suited to detect these changes in subsurface water saturation. Since the water saturation of the sediments is directly correlated to the mechanical properties and therefore the stability of the slope, the changes in the water saturations are directly correlated with the landslide stability or safety factor. Additional to these field investigations also petrophysical measurements had been done on typical samples gathered in the landslide area to get calibration values. Also a limited set of meteorological data of the area had been available. The data gathered during the research project showed already a very high risk for a landslide event. Local authorities had been informed and two public information articles had been published two and one year in advance of the slide event in a local

Landslide fatalities in the Western Ghats of Kerala, India

NASA Astrophysics Data System (ADS)

Lukose Kuriakose, Sekhar; Sankar, G.; Muraleedharan, C.

2010-05-01

The Western Ghats of Kerala, India is prone to shallow landslides and consequent debris flows. An earlier study (Kuriakose et al., EG, 2009) has compiled and presented the history and chorology of landslide prone areas of the region. An attempt to collect and compile a reliable fatal landslide inventory of the region resulted in a database of 63 landslides from 1961 to 2009. The data base was compiled from the news paper reports and research reports of the CESS and GSI. Most landslides were visited in and the locations were mapped using a handheld GPS. Date and fatality information was also collected. For twelve of the landslides accurate location information was not available and hence was plotted at the nearest known village centre. Three landslides did not have any location information but was recorded in the district gazetteer and hence included in the data base. A total of 257 valuable lives were lost in landslides. The landslide that caused the highest number of deaths was the Amboori landslide (Thiruvananthapuram) which occurred on 11 September 2001 that caused 39 fatalities. Idukki district experienced the largest number of fatal landslides during this period, 20 events resulting in 67 fatalities. Thiruvananthapuram district experienced the highest average number of fatalities per landslide (47 deaths from 5 events). The district wise statistics from north to south are, Kannur (6 from 5), Kasargodu (24 from 6), Wayanad (36 from 6), Kozhikode (44 from 10), Malappuram (9 from 3), Palakkad (3 from 3), Thrissur (2 from 1), Kottayam (5 from 3), and Pathanamthitta (14 from 3). It was noted that there exists a spatial trend in the occurrence of fatal landslides which follows the general monsoon rainfall trends and the population density. About 55% of the events occurred during the south west monsoon (June to September) season. It was also observed that there exists a strong upward trend in the number of fatal landslides. This upward trend can be directly

Hydrologic Controls on Shallow Landslide Location, Size, and Shape

NASA Astrophysics Data System (ADS)

Bellugi, D.; Milledge, D.; Perron, T.; McKean, J. A.; Dietrich, W.; Rulli, M.

2012-12-01

Shallow landslides, typically involving just the soil mantle, are principally controlled by topography, soil and root strengths, and soil thickness, and are typically triggered by storm-induced increases in pore water pressure. The response of a landscape to landslide-triggering storms will thus depend on factors such as rainfall totals, storm intensity and duration, and antecedent moisture conditions. The two dominant mechanisms that generate high pore water pressures at a point are topographically-steered lateral subsurface flow (over timescales of days to weeks), and rapid vertical infiltration (over timescales of minutes to hours). We aim to understand the impact of different storm characteristics and hydrologic regimes on shallow landslide location, size, and shape. We have developed a regional-scale model, which applies a low-parameter grid-based multi-dimensional slope stability model within a novel search algorithm, to generate discrete landslide predictions. This model shows that the spatial organization of parameters such as root strength and pore water pressure has a strong control on shallow landslide location, size, and shape. We apply this model to a field site near Coos Bay, OR, where a ten-year landslide inventory has been mapped onto high-resolution topographic data. Our model predicts landslide size generally increases with increasing rainfall intensity, except when root strength is extremely high and pore pressures are topographically steered. The distribution of topographic index values (the ratios of contributing area to slope) of predicted landslides is a clear signature of the pore water pressure generation mechanism: as laterally dominated flow increases, landslides develop in locations with lower slopes and higher contributing areas; in contrast, in the case of vertically-dominated pore pressure rise, landslides are consistently found in locations with higher slopes and lower contributing areas. While in both cases landslides are found in

Dam break analysis and flood inundation map of Krisak dam for emergency action plan

NASA Astrophysics Data System (ADS)

Juliastuti, Setyandito, Oki

2017-11-01

The Indonesian Regulation which refers to the ICOLD Regulation (International Committee on Large Dam required have the Emergency Action Plan (EAP) guidelines because of the dams have potential failure. In EAP guidelines there is a management of evacuation where the determination of the inundation map based on flood modeling. The purpose of the EAP is to minimize the risk of loss of life and property in downstream which caused by dam failure. This paper will describe about develop flood modeling and inundation map in Krisak dam using numerical methods through dam break analysis (DBA) using hydraulic model Zhong Xing HY-21. The approaches of dam failure simulation are overtopping and piping. Overtopping simulation based on quadrangular, triangular and trapezium fracture. Piping simulation based on cracks of orifice. Using results of DBA, hazard classification of Krisak dam is very high. The nearest village affected dam failure is Singodutan village (distance is 1.45 kilometer from dam) with inundation depth is 1.85 meter. This result can be used by stakeholders such as emergency responders and the community at risk in formulating evacuation procedure.

Preliminary ground response of the Diezma landslide (Southern Spain)

NASA Astrophysics Data System (ADS)

Delgado, José; García-Tortosa, Francisco J.; Garrido, Jesús; Lenti, Luca; López-Casado, Carlos; Martino, Salvatore; Peláez, José A.; Sanz de Galdeano, Carlos

2015-04-01

The reactivation of landslides is a major concern in regions of moderate to high seismicity, especially when it affects roads or villages. The Diezma landslide (Southern Spain), which had an estimated volume of 1.2 Mm3 and affected the main highway of Andalusia (A-92), it is located in a region of moderate seismicity and it has been active since 1998, but some local reactivations keep going after the general failure occurred in 2001, despite of the corrective measures built after the main failure. A heavy rain period was the triggering factor of the landslide, therefore future rains and mainly earthquakes may destabilize the whole slope again. An engineering-geological model of the landslide was developed from field surveys, laboratory tests, boreholes logs and geophysical investigations (MASW and seismic noise measurements). The landslide mass is constituted by silts and clays with heterometric blocks sliding on a metamorphic bedrock, and its mechanism was conditioned by structural constraints. The ground response o f the landslide was studied through experimental techniques including ambient noise and earthquake records. The ambient noise survey was designed for the use of the Nakamura's HVSR technique. While the measurements done inside the landslide exhibit a sharp peak whose peak frequency varies depending of the site within the landslide mass, those made outside landslide mass are characterized by a flat response. A temporary seismic network (0-30 s broadband seismometers), set up inside the landslide and in rocky outcrops outside the landslide, has allowed to record up to 20 earthquakes with epicentral distances from local to distant earthquakes, and magnitudes ranging from 1.7 to 7.2, showing similar spectral response to that retrieved from noise measurements. An unconventional pseudostatic analysis was applied to the landslide under limit equilibrium conditions through several sine waves, which cause accelerations which values are in the range of the

How big of an effect do small dams have? Using geomorphological footprints to quantify spatial impact of low-head dams and identify patterns of across-dam variation

USGS Publications Warehouse

Fencl, Jane S.; Mather, Martha E.; Costigan, Katie H.; Daniels, Melinda D.

2015-01-01

Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (<7.6 m high) fragment United States rivers. Despite potential adverse impacts of these ubiquitous disturbances, the spatial impacts of low-head dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0–15.3 km) or 287 wetted widths (136–437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic

How Big of an Effect Do Small Dams Have? Using Geomorphological Footprints to Quantify Spatial Impact of Low-Head Dams and Identify Patterns of Across-Dam Variation

PubMed Central

Costigan, Katie H.; Daniels, Melinda D.

2015-01-01

Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (<7.6 m high) fragment United States rivers. Despite potential adverse impacts of these ubiquitous disturbances, the spatial impacts of low-head dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0–15.3 km) or 287 wetted widths (136–437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic

Landslide deposit boundaries for the Little North Santiam River Basin, Oregon

USGS Publications Warehouse

Sobieszczyk, Steven

2010-01-01

This layer is an inventory of existing landslides deposits in the Little North Santiam River Basin, Oregon (2009). Each landslide deposit shown on this map has been classified according to a number of specific characteristics identified at the time recorded in the GIS database. The classification scheme was developed by the Oregon Department of Geology and Mineral Industries (Burns and Madin, 2009). Several significant landslide characteristics recorded in the database are portrayed with symbology on this map. The specific characteristics shown for each landslide are the activity of landsliding, landslide features, deep or shallow failure, type of landslide movement, and confidence of landslide interpretation. These landslide characteristics are determined primarily on the basis of geomorphic features, or landforms, observed for each landslide. This work was completed as part of the Master's thesis "Turbidity Monitoring and LiDAR Imagery Indicate Landslides are Primary Source of Suspended-Sediment Load in the Little North Santiam River Basin, Oregon, Winter 2009-2010" by Steven Sobieszczyk, Portland State University and U.S. Geological Survey.Data layers in this geodatabase include: landslide deposit boundaries (Deposits); field-verfied location imagery (Photos); head scarp or scarp flanks (Scarp_Flanks); and secondary scarp features (Scarps).The geodatabase template was developed by the Oregon Department of Geology and Mineral Industries (Burns and Madin, 2009).

Boulders on a Landslide

NASA Image and Video Library

2015-12-23

The striking feature in this image from NASA Mars Reconnaissance Orbiter is a boulder-covered landslide along a canyon wall. Landslides occur when steep slopes fail, sending a mass of soil and rock to flow downhill, leaving behind a scarp at the top of the slope. The mass of material comes to rest when it reaches shallower slopes, forming a lobe of material that ends in a well-defined edge called a toe. http://photojournal.jpl.nasa.gov/catalog/PIA20290

Small Landslide in Kasei

NASA Technical Reports Server (NTRS)

2004-01-01

21 February 2004 The finger-shaped lobe just right of center in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image is the deposit of a small landslide that came down a dark, layered slope. Landslides are common on Mars in areas of steep topography; this one is located in the Kasei Valles region near 23.9oN, 67.1oW. Sunlight illuminates the scene from the lower left; the picture covers an area 3 km (1.9 mi) wide.

Clayey Landslide Initiation and Acceleration Strongly Modulated by Soil Swelling

NASA Astrophysics Data System (ADS)

Schulz, William H.; Smith, Joel B.; Wang, Gonghui; Jiang, Yao; Roering, Joshua J.

2018-02-01

Largely unknown mechanisms restrain motion of clay-rich, slow-moving landslides that are widespread worldwide and rarely accelerate catastrophically. We studied a clayey, slow-moving landslide typical of thousands in Northern California, USA, to decipher hydrologic-mechanical interactions that modulate landslide dynamics. Similar to some other studies, observed pore-water pressures correlated poorly with landslide reactivation and speed. In situ and laboratory measurements strongly suggested that variable pressure along the landslide's lateral shear boundaries resulting from seasonal soil expansion and contraction modulated its reactivation and speed. Slope-stability modeling suggested that the landslide's observed behavior could be predicted by including transient swell pressure as a resistance term, whereas modeling considering only transient hydrologic conditions predicted movement five to six months prior to when it was observed. All clayey soils swell to some degree; hence, our findings suggest that swell pressure likely modulates motion of many landslides and should be considered to improve forecasts of clayey landslide initiation and mobility.

Clayey landslide initiation and acceleration strongly modulated by soil swelling

USGS Publications Warehouse

Schulz, William; Smith, Joel B.; Wang, Gonghui; Jiang, Yao; Roering, Joshua J.

2018-01-01

Largely unknown mechanisms restrain motion of clay-rich, slow-moving landslides that are widespread worldwide and rarely accelerate catastrophically. We studied a clayey, slow-moving landslide typical of thousands in northern California, USA, to decipher hydrologic-mechanical interactions that modulate landslide dynamics. Similar to some other studies, observed pore-water pressures correlated poorly with landslide reactivation and speed. In situ and laboratory measurements strongly suggested that variable pressure along the landslide's lateral shear boundaries resulting from seasonal soil expansion and contraction modulated its reactivation and speed. Slope-stability modeling suggested that the landslide's observed behavior could be predicted by including transient swell pressure as a resistance term, whereas modeling considering only transient hydrologic conditions predicted movement 5–6 months prior to when it was observed. All clayey soils swell to some degree; hence, our findings suggest that swell pressure likely modulates motion of many landslides and should be considered to improve forecasts of clayey landslide initiation and mobility.

Characteristics of Landslide Size Distribution in Response to Different Rainfall Scenarios

NASA Astrophysics Data System (ADS)

Wu, Y.; Lan, H.; Li, L.

2017-12-01

There have long been controversies on the characteristics of landslide size distribution in response to different rainfall scenarios. For inspecting the characteristics, we have collected a large amount of data, including shallow landslide inventory with landslide areas and landslide occurrence times recorded, and a longtime daily rainfall series fully covering all the landslide occurrences. Three indexes were adopted to quantitatively describe the characteristics of landslide-related rainfall events, which are rainfall duration, rainfall intensity, and the number of rainy days. The first index, rainfall duration, is derived from the exceptional character of a landslide-related rainfall event, which can be explained in terms of the recurrence interval or return period, according to the extreme value theory. The second index, rainfall intensity, is the average rainfall in this duration. The third index is the number of rainy days in this duration. These three indexes were normalized using the standard score method to ensure that they are in the same order of magnitude. Based on these three indexes, landslide-related rainfall events were categorized by a k-means method into four scenarios: moderate rainfall, storm, long-duration rainfall, and long-duration intermittent rainfall. Then, landslides were in turn categorized into four groups according to the scenarios of rainfall events related to them. Inverse-gamma distribution was applied to characterize the area distributions of the four different landslide groups. A tail index and a rollover of the landslide size distribution can be obtained according to the parameters of the distribution. Characteristics of landslide size distribution show that the rollovers of the size distributions of landslides related to storm and long-duration rainfall are larger than those of landslides in the other two groups. It may indicate that the location of rollover may shift right with the increase of rainfall intensity and the

Costs and deaths of landslides in Europe

NASA Astrophysics Data System (ADS)

Haque, Ubydul; Blum, Philipp

2016-04-01

Landslides cause human and large economic losses worldwide and also in Europe. However, the quantification of associated costs and deaths is highly underestimated and still incomplete, thus the estimation of landslide costs and risk is still rather ambitious. Hence, in this study a spatio-temporal analysis of fatal landslides is presented for 27 European countries from 1995-2014. These landslides are mainly concentrated in mountainous areas. A total of 1370 fatalities are reported resulting from 476 landslides. The highest fatalities with 335 are observed in Turkey. In general, an increasing trend of fatal landslides is recognized starting in 2008. The latter is almost certainly triggered by an increase in natural extreme events such as storms (i.e. heavy rainfall) and floods. The highest annual economic loss is observed in Italy with 3.9 billion Euro per year. In contrast, in Germany the annual total loss is only about 0.3 billion Euro. The results of this study serves as an initial baseline information for further risk studies integrating landslide locations, local land use data, cost data, and will therefore certainly support the studied countries to better protect their citizens and assets. Acknowledgements We would like to acknowledge the valuable contributions by Paula F. da Silva, Peter Andersen, Jürgen Pilz, Ali Ardalan, Sergey R. Chalov, Jean-Philippe Malet, Mateja Jemec Auflič, Norina Andres, Eleftheria Poyiadji, Pedro C. Lamas, Wenyi Zhang, Igor Pesevski, Halldór G. Pétursson, Tayfun Kurt, Nikolai Dobrev, Juan Carlos García Davalillo, Matina Halkia, Stefano Ferri, George Gaprindashvili, Johanna Engström and David Keellings.

Undersea landslides: Extent and significance in the Pacific Ocean, an update

USGS Publications Warehouse

Lee, H.J.

2005-01-01

Submarine landslides are known to occur disproportionately in a limited number of environments including fjords, deltas, canyons, volcanic islands and the open continental slope. An evaluation of the progress that has been made in understanding Pacific Ocean submarine landslides over the last 15 years shows that mapping technologies have improved greatly, allowing a better interpretation of landslide features. Some features previously identified as landslides are being reinterpreted by some as sediment waves. Previously underappreciated environments for landslides such as deep-sea trenches are being recognized and lava deltas are being found to be landslide prone. Landslides are also being recognized much more commonly as a potential source of tsunamis. Landslides that have produced tsunamis in the past are being mapped and in some cases modeled. The flow characteristics of turbidity currents produced by landslides in canyon heads have recently been monitored and the source of these failures has been identified using repeated multibeam mapping. Finally, some landslide deposits are being dated as part of assessing risk to coastal cities from landslide-tsunamis. European Geosciences Union ?? 2005 Author(s). This work is licensed under a Creative Commons License.

Deformation Monitoring and Bathymetry Analyses in Rock-Fill Dams, a Case Study at Ataturk Dam

NASA Astrophysics Data System (ADS)

Kalkan, Y.; Bilgi, S.

2014-12-01

Turkey has 595 dams constructed between 1936 and 2013 for the purposes of irrigation, flood control, hydroelectric energy and drinking water. A major portion of the dam basins in Turkey are deprived of vegetation and have slope topography on near surrounding area. However, landscaping covered with forest around the dam basin is desirable for erosion control. In fact; the dams, have basins deprived of vegetation, fill up quickly due to sediment transport. Erosion control and forestation are important factors, reducing the sediment, to protect the water basins of the dams and increase the functioning life of the dams. The functioning life of dams is as important as the investment and construction. Nevertheless, in order to provide safety of human life living around, well planned monitoring is essential for dams. Dams are very large and critical structures and they demand the use or application of precise measuring systems. Some basic physical data are very important for assessing the safety and performance of dams. These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. Monitoring is an essential component of the dam after construction and during operation and must en­able the timely detection of any behavior that could deteriorate the dam, potentially result in its shutdown or failure. Considering the time and labor consumed by long-term measurements, processing and analysis of measured data, importance of the small structural motions at regular intervals could be comprehended. This study provides some information, safety and the techniques about the deformation monitoring of the dams, dam safety and related analysis. The case study is the deformation measurements of Atatürk Dam in Turkey which is the 6th largest dam of world considering the filling volume of embankment. Brief information is given about the

Landslide susceptibility in the Tully Valley area, Finger Lakes region, New York

USGS Publications Warehouse

Jager, Stefan; Wieczorek, Gerald E.

1994-01-01

As a consequence of a large landslide in the Tully Valley, Onondaga County, New York, an investigation was undertaken to determine the factors responsible for the landslide in order to develop a model for regional landslide susceptibility. The April 27, 1993 Tully Valley landslide occurred within glacial lake clays overlain by till and colluvium on gentle slopes of 9-12 degrees. The landslide was triggered by extreme climatic events of prolonged heavy rainfall combined with rapid melting of a winter snowpack. A photoinventory and field checking of landslides within a 415 km2 study area, including the Tully Valley, revealed small recently-active landslides and other large dormant prehistoric landslides, probably Pleistocene in age. Similar to the larger Tully Valley landslide, the smaller recently-active landslides occurred in red, glacial lake clays very likely triggered by seasonal rainfall. The large dormant landslides have been stable for long periods as evidenced by slope denudational processes that have modified the landslides. These old and ancient landslides correspond with proglacial lake levels during the Pleistocene, suggesting that either inundation or rapid drainage was responsible for triggering these landslides. A logistic regression analysis was performed within a Geographic Information System (GIS) environment to develop a model of landslide susceptibility for the Tully Valley study area. Presence of glacial clays, slope angle, and glacial lake levels were used as explanatory variables for landslide incidence. The spatial probability of landsliding, categorized as low, moderate and high, is portrayed within 90-m square cells on the susceptibility map.

Effects of Inventory Bias on Landslide Susceptibility Calculations

NASA Technical Reports Server (NTRS)

Stanley, T. A.; Kirschbaum, D. B.

2017-01-01

Many landslide inventories are known to be biased, especially inventories for large regions such as Oregon's SLIDO or NASA's Global Landslide Catalog. These biases must affect the results of empirically derived susceptibility models to some degree. We evaluated the strength of the susceptibility model distortion from postulated biases by truncating an unbiased inventory. We generated a synthetic inventory from an existing landslide susceptibility map of Oregon, then removed landslides from this inventory to simulate the effects of reporting biases likely to affect inventories in this region, namely population and infrastructure effects. Logistic regression models were fitted to the modified inventories. Then the process of biasing a susceptibility model was repeated with SLIDO data. We evaluated each susceptibility model with qualitative and quantitative methods. Results suggest that the effects of landslide inventory bias on empirical models should not be ignored, even if those models are, in some cases, useful. We suggest fitting models in well-documented areas and extrapolating across the study region as a possible approach to modeling landslide susceptibility with heavily biased inventories.

Effects of Inventory Bias on Landslide Susceptibility Calculations

NASA Technical Reports Server (NTRS)

Stanley, Thomas; Kirschbaum, Dalia B.

2017-01-01

Many landslide inventories are known to be biased, especially inventories for large regions such as Oregons SLIDO or NASAs Global Landslide Catalog. These biases must affect the results of empirically derived susceptibility models to some degree. We evaluated the strength of the susceptibility model distortion from postulated biases by truncating an unbiased inventory. We generated a synthetic inventory from an existing landslide susceptibility map of Oregon, then removed landslides from this inventory to simulate the effects of reporting biases likely to affect inventories in this region, namely population and infrastructure effects. Logistic regression models were fitted to the modified inventories. Then the process of biasing a susceptibility model was repeated with SLIDO data. We evaluated each susceptibility model with qualitative and quantitative methods. Results suggest that the effects of landslide inventory bias on empirical models should not be ignored, even if those models are, in some cases, useful. We suggest fitting models in well-documented areas and extrapolating across the study region as a possible approach to modelling landslide susceptibility with heavily biased inventories.

A Heuristic Approach to Global Landslide Susceptibility Mapping

NASA Technical Reports Server (NTRS)

Stanley, Thomas; Kirschbaum, Dalia B.

2017-01-01

Landslides can have significant and pervasive impacts to life and property around the world. Several attempts have been made to predict the geographic distribution of landslide activity at continental and global scales. These efforts shared common traits such as resolution, modeling approach, and explanatory variables. The lessons learned from prior research have been applied to build a new global susceptibility map from existing and previously unavailable data. Data on slope, faults, geology, forest loss, and road networks were combined using a heuristic fuzzy approach. The map was evaluated with a Global Landslide Catalog developed at the National Aeronautics and Space Administration, as well as several local landslide inventories. Comparisons to similar susceptibility maps suggest that the subjective methods commonly used at this scale are, for the most part, reproducible. However, comparisons of landslide susceptibility across spatial scales must take into account the susceptibility of the local subset relative to the larger study area. The new global landslide susceptibility map is intended for use in disaster planning, situational awareness, and for incorporation into global decision support systems.

Landslide risk in the San Francisco Bay region

USGS Publications Warehouse

Coe, J.A.; Crovelli, R.A.

2008-01-01

We have used historical records of damaging landslides triggered by rainstorms, and a newly developed Probabilistic Landslide Assessment Cost Estimation System (PLACES), to estimate the numbers and direct costs of future landslides in the San Francisco Bay region. The estimated annual cost of future landslides in the entire region is about US $15 million (year 2000 $). The estimated annual cost is highest for San Mateo County ($3.32 million) and lowest for Solano County ($0.18 million). Normalizing costs by dividing by the percentage of land area with slopes equal or greater than about 10° indicates that San Francisco County will have the highest cost per square km ($7,400), whereas Santa Clara County will have the lowest cost per square km ($230). These results indicate that the San Francisco Bay region has one of the highest levels of landslide risk in the United States. Compared to landslide cost estimates from the rest of the world, the risk level in the Bay region seems high, but not exceptionally high.

Landslide characteristics and spatial distribution in the Rwenzori Mountains, Uganda

NASA Astrophysics Data System (ADS)

Jacobs, Liesbet; Dewitte, Olivier; Poesen, Jean; Maes, Jan; Mertens, Kewan; Sekajugo, John; Kervyn, Matthieu

2017-10-01

In many landslide-prone regions, data on landslide characteristics remain poor or inexistent. This is also the case for the Rwenzori Mountains, located on the border of Uganda and the DR Congo. There, landslides frequently occur and cause fatalities and substantial damage to private property and infrastructure. In this paper, we present the results of a field inventory performed in three representative study areas covering 114 km2. A total of 371 landslides were mapped and analyzed for their geomorphological characteristics and their spatial distribution. The average landslide areas varied from less than 0.3 ha in the gneiss-dominated highlands to >1 ha in the rift alluvium of the lowlands. Large landslides (>1.5 ha) are well represented while smaller landslides (<1.5 ha) are underrepresented. The degrees of completeness of the field inventories are comparable to those of similar historical landslide inventories. The diversity of potential mass movements in the Rwenzori is large and depends on the dominant lithological and topographic conditions. A dominance of shallow translational soil slides in gneiss and of deep rotational soil slides in the rift alluvium is observed. Slope angle is the main controlling topographic factor for landslides with the highest landslide concentrations for slope angles above 25-30° in the highlands and 10-15° in the lowlands. The undercutting of slopes by rivers and excavations for construction are important preparatory factors. Rainfall-triggered landslides are the most common in the area, however in the zones of influence of the last two major earthquakes (1966: Mw = 6.6 and 1994: Mw = 6.2), 12 co-seismic landslides were also observed.

Exploiting Synthetic Aperture Radar data to map and observe landslides

NASA Astrophysics Data System (ADS)

Bekaert, D. P.; Agram, P. S.; Fattahi, H.; Kirschbaum, D.; Amatya, P. M.; Stanley, T.

2017-12-01

Synthetic Aperture Radar instruments onboard satellites or airborne platforms are a powerful means to study landslides. How to best exploit the data and which techniques to apply strongly depend on the region of study and the landslide type which occurs. The amount of vegetation, snowfall, and steepness of the terrain, as well the shadowing effects of the mountain will determine if SAR is suitable to map a given landslide. Fast moving landslides occurring over a large area (e.g. >100 m) could benefit from pixel or feature tracking, while for slower moving landslides Interferometric SAR could be a more favorable approach. However, neither of those methods would work for critical landslide failures which do not preserve surface features. This type of slides would benefit from a change detection approach. Here we look at these three different cases and utilize Sentinel-1 space-borne SAR data and state-of-the-art processing techniques to map multiple landslides along the California State Route 1 and the Trishuli highway in the Langtang valley of Nepal. Our findings correlate with existing landslide catalogues and also identify landslides in regions earlier mapped to be dormant.

Landslide study at Sacele reservoir in Romania

NASA Astrophysics Data System (ADS)

Cannata, Massimiliano; Ambrosi, Christian; Spataro, Alessio; Martin, James; Olgun, Guney

2010-05-01

Sacele reservoir is locate on the river Tàrlung, about 3 Km upstream from Sacele and about 12 Km from Brasov (Romania). It represents the main drinking water source for Brasov. The Sacele reservoir is recognized as a dam of exceptional importance and therefore it requires special surveillance. In the East side of the basin, in proximity of the barrage, the slope shows evidences of instability; for this reason stabilization works, mainly consisting in re-profiling the slope, and drainage installation, has been conducted without success. This study, financed by the World Bank, aims to provide important information for the estabilishment of an authomatic monitoring system able to reduce the existing risk. Conducted studies includes: - analysis of existing informations - data acquisition by mean of field survey (geodetical and gelogical) and in situ investigation (boreholes, geophisical, sample test) - developement of GIS based geological model - developement of landslide models based on FLAC and FLAC3D Finally the model results leading to the identification of the triggering factors are discussed. The conducted work is a comprehensive study (from data to models) that highligth some interesting conclusions showing how the "stabilization" works increased total displacements and shear strain, and produced a new deeper cinematic.

Stereo Pair, Lake Palanskoye Landslide, Kamchatka Peninsula, Russia

NASA Technical Reports Server (NTRS)

2000-01-01

The Lake Palanskoye in northern Kamchatka was formed when a large landslide disrupted the drainage pattern, forming a natural dam. The area is volcanically and tectonically active and it is likely that the landslide -- which covers about 80 square kilometers (30 square miles) --was triggered by an earthquake sometime in the past 10,000 years. The source area of the landslide is the ridge between the two bright rocky features to the lower left of the lake. In 3-D, the steep topographic scar at the head of the slide and the broad expanse of hummocky landslide debris that covers the valley just below the lake are visible. This Landsat/SRTM stereoscopic view is an enhanced true color image: Vegetation appears green, rocks are brownish, snow is white and water (such as the lake) appears very dark.

This stereoscopic image pair was generated using topographic data from SRTM combined with a Landsat 7 satellite image collected the previous summer. The topography data were used to create two differing perspectives of a single image -- one for each eye. Depending on its elevation, each point in the image was shifted slightly. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30 meter(99 foot) spatial resolution of most Landsat images and will provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, South Dakota.

The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space

Geomorphological mapping of shallow landslides using UAVs

NASA Astrophysics Data System (ADS)

Fiorucci, Federica; Giordan, Daniele; Dutto, Furio; Rossi, Mauro; Guzzetti, Fausto

2015-04-01

The mapping of event shallow landslides is a critical activity, due to the large number of phenomena, mostly with small dimension, affecting extensive areas. This is commonly done through aerial photo-interpretation or through field surveys. Nowadays, landslide maps can be realized exploiting other methods/technologies: (i) airborne LiDARs, (ii) stereoscopic satellite images, and (iii) unmanned aerial vehicles (UAVs). In addition to the landslide maps, these methods/technologies allow the generation of updated Digital Terrain Models (DTM). In December 2013, in the Collazzone area (Umbria, Central Italy), an intense rainfall event triggered a large number of shallow landslides. To map the landslides occurred in the area, we exploited data and images obtained through (A) an airborne LiDAR survey, (B) a remote controlled optocopter (equipped with a Canon EOS M) survey, and (C) a stereoscopic satellite WorldView II MS. To evaluate the mapping accuracy of these methods, we select two landslides and we mapped them using a GPS RTK instrumentation. We consider the GPS survey as the benchmark being the most accurate system. The results of the comparison allow to highlight pros and cons of the methods/technologies used. LiDAR can be considered the most accurate system and in addition it allows the extraction and the classification of the digital surface models from the surveyed point cloud. Conversely, LiDAR requires additional time for the flight planning, and specific data analysis user capabilities. The analysis of the satellite WorldView II MS images facilitates the landslide mapping over large areas, but at the expenses of a minor resolution to detect the smaller landslides and their boundaries. UAVs can be considered the cheapest and fastest solution for the acquisition of high resolution ortho-photographs on limited areas, and the best solution for a multi-temporal analysis of specific landslide phenomena. Limitations are due to (i) the needs of optimal climatic

Regional analysis of distribution of pre and post 2015 Nepal Earthquake landslides

NASA Astrophysics Data System (ADS)

Valagussa, Andrea; Frattini, Paolo; Crosta, Giovanni; Valbuzzi, Elena

2016-04-01

A magnitude 7.8 earthquake struck Nepal on April 25, 2015. Three landslide inventories have been prepared in four districts: Dhading (1885 km2), Sindhupalchok (2488 km2), Rasuwa (1522 km2) and Nuwakot (1194 km2), that are located north of Kathmandu. These inventories extend 14 to 138 km SE from the epicenter of the main shock (April 25, 2015), 4.5 to 143 km NW from the epicenter of the main aftershock (May 12, 2015), and 34 to 136 km from the Main Frontal Thrust. The first inventory is a coseismic and post-seismic landslide inventory based on multi-temporal images (Google Earth, Google Crisis maps, Bing maps), and helicopter-based video. The second one is a pre-event shallow landslide inventory. In these two inventories the most abundant landslide types are: debris flows, shallow translational slides, and rockfalls. The third is a deep seated landslide inventory, in which the most represented landslide types are rock avalanches, slumps, rockslides and deep-seated gravitational slope deformations (DSGSD). All the landslides have been mapped as individual polygons. For the analysis we focus our attention on four districts: First we studied how the landslide frequency density changes as a function of topographic parameters (i.e. slope gradient, slope aspect, and elevation). The analyses have been based on the ASTER Global Digital Elevation Model (ASTER GDEM). For coseismic and post-seismic landslides we observed that the mean slope gradient at which the landslide occurs is higher with respect to the two other inventories (50° and 30/40° respectively). The slope aspect of coseismic and post-seismic landslides is also different, with a larger frequency of landslides towards SW, whereas in pre-event landslides the most common slope aspect is SE. This could be related to the direction of the seismic wave. At least the coseismic and post-seismic landslides occur, in mean, at an elevation lower than the pre-event landslides. We also analyzed the relationship between the

Floristic and vegetation successional processes within landslides in a Mediterranean environment.

PubMed

Neto, Carlos; Cardigos, Patrícia; Oliveira, Sérgio Cruz; Zêzere, José Luís

2017-01-01

Floristic and vegetation analysis in seven Mediterranean landslides led to the understanding of the successional processes occurring in different landslide disturbed sectors. Our study showed that in landslides that occurred between 1996 and 2010 there is a clear differentiation between the three main landslide sectors (scarp, main body and foot) concerning floristic composition, vegetation structure, floristic richness, successional processes and plant functional type. Additional differences were found between landslide areas and undisturbed agricultural areas adjacent to landslides. In this study 48 floristic relevés were made using a stratified random sampling design. The main landslide body exhibits the highest floristic richness whereas the landslide scarp has the lowest coverage rate and the highest presence of characteristic species from ruderal and strongly perturbed habitats. Finally, the landslide foot shows a late stage in the succession (maquis or pre-forest stage) with a high dominance of vines. We further discuss the importance of landslides as reservoirs of biodiversity especially for Mediterranean orchids. Copyright © 2016 Elsevier B.V. All rights reserved.

Tharsis Landslide

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

The landslide in the VIS image occurs in the Tharsis region of Mars, just north of Hebes Chasma. The volcanic flows forming the lower surface in the image have a platy texture. The landslide is younger than the volcanic flow, as the landslide sits on top of the flow surface.

Image information: VIS instrument. Latitude 5, Longitude 282.4 East (77.6 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Landslide and Land Subsidence Hazards to Pipelines

USGS Publications Warehouse

Baum, Rex L.; Galloway, Devin L.; Harp, Edwin L.

2008-01-01

Landslides and land subsidence pose serious hazards to pipelines throughout the world. Many existing pipeline corridors and more and more new pipelines cross terrain that is affected by either landslides, land subsidence, or both. Consequently the pipeline industry recognizes a need for increased awareness of methods for identifying and evaluating landslide and subsidence hazard for pipeline corridors. This report was prepared in cooperation with the U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration, and Pipeline Research Council International through a cooperative research and development agreement (CRADA) with DGH Consulting, Inc., to address the need for up-to-date information about current methods to identify and assess these hazards. Chapters in this report (1) describe methods for evaluating landslide hazard on a regional basis, (2) describe the various types of land subsidence hazard in the United States and available methods for identifying and quantifying subsidence, and (3) summarize current methods for investigating individual landslides. In addition to the descriptions, this report provides information about the relative costs, limitations and reliability of various methods.

Landslide Caused Damages in a Gallery

NASA Astrophysics Data System (ADS)

Poisel, R.; Mair am Tinkhof, K.; Preh, A.

2016-06-01

On October 5th, 2010, cracks were found in a gallery 1.8 m high and 1.4 m wide. The gallery is 100 years old, runs parallel to a valley flank and was excavated in a tectonically strongly stressed, weathered and slightly dipping sandwich of clayey shales, sandstones and marls. The cracks in the roof as well as in the invert ran parallel to the axis of the gallery. Monitoring showed that crack widths were increasing 1.5 mm per year, sidewall distances were increasing 3.5 mm per year, whereas the height of the gallery was decreasing 2.5 mm per year. After eliminating several possible causes of cracking, a landslide producing the damages had to be taken into consideration. Monitoring of the valley flank surface as well as inclinometer readings revealed that a landslide was occurring, loading the gallery lining. Most probably the landslide had been reactivated by excessive rainfall in 2009 as well as by works for the renewal of a weir in the valley bottom. As stabilization of the slope was not an option for several reasons, it was decided to replace the gallery by a new one deeper inside the slope, which will be ready for operation in 2017. Thus the old gallery has to be kept in operation till then and it was decided to reinforce the old gallery by a heavily reinforced shotcrete lining 10 cm thick. As slope displacements went on, cracks in the shotcrete lining developed with a completely different pattern: in the section where the gallery lies completely in the landslide shear zone no cracks formed until now due to heavy reinforcement, whereas in the transition sections stable ground-landslide and landslide-stable ground diagonal tension cracks in the roof due to shear by the landslide developed. Numerical models showed that cracking and spalling of the shotcrete lining would occur only after some centimetres of additional displacements of the slope, which hopefully will not occur before 2017.

Landslides along Highways: GIS-based Inventory and Planning Issues

NASA Astrophysics Data System (ADS)

Jaeger, Ann-Kathrin; Klose, Martin; Damm, Bodo

2015-04-01

Highways rank as critical transportation infrastructures that are at risk of landslides in many areas worldwide (e.g., Hungr et al., 1999; Bhandary et al., 2013). Safe and affordable operations of traffic routes constitute the two main criteria for transportation planning in landslide-prone terrain. A right balancing of these often conflicting priorities requires profound knowledge of landslide locations across highway networks and the costs caused by landslides in the past (e.g., Saha et al., 2005). Much of the direct costs affecting transportation departments relate to capital investments for landslide repair or mitigation and operational expenditures in connection with maintenance works. A systematic collection and inventory of such data sets combined with an acquisition of hazard information on vulnerable road sections is still rarely the case in engineering practice. This is despite significant cost impacts and budgetary burdens, especially in peripheral mountain areas where financial resources are naturally limited (e.g., Klose et al., 2014). The present contribution introduces a regional inventory of landslides along highways in the Harz Mountains, NW Germany. As subset of a landslide database for the entire country, this focused GIS-based inventory has been compiled in close collaboration with the Lower Saxony Department of Transportation. The inventory includes data sets gathered by archive studies and relies on high-quality information sources such as maintenance protocols, geotechnical reports, and documents from tendering, controlling, and accounting. A mapping tool in ArcGIS format is used to specify and visualize road sections affected by landslides. This spatial information on hazard exposure is complemented by narrative risk profiles for landslide sites showing a long history of damage events. By summarizing the occurrence dates of landslides, the associated damages, and the types and costs of repair or prevention, such risk profiles are useful to

Modeling tsunamis induced by retrogressive submarine landslides

NASA Astrophysics Data System (ADS)

Løvholt, F.; Kim, J.; Harbitz, C. B.

2015-12-01

Enormous submarine landslides having volumes up to thousands of km3 and long run-out may cause tsunamis with widespread effects. Clay-rich landslides, such as Trænadjupet and Storegga offshore Norway commonly involve retrogressive mass and momentum release mechanisms that affect the tsunami generation. Therefore, such landslides may involve a large amount of smaller blocks. As a consequence, the failure mechanisms and release rate of the individual blocks are of importance for the tsunami generation. Previous attempts to model the tsunami generation due to retrogressive landslides are few, and limited to idealized conditions. Here, we review the basic effects of retrogression on tsunamigenesis in simple geometries. To this end, two different methods are employed for the landslide motion, a series block with pre-scribed time lags and kinematics, and a dynamic retrogressive model where the inter-block time lag is determined by the model. The effect of parameters such as time lag on wave-height, wave-length, and dispersion are discussed. Finally, we discuss how the retrogressive effects may have influenced the tsunamis due to large landslides such as the Storegga slide. The research leading to these results has received funding from the Research Council of Norway under grant number 231252 (Project TsunamiLand) and the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement 603839 (Project ASTARTE).

Optimized volume models of earthquake-triggered landslides

PubMed Central

Xu, Chong; Xu, Xiwei; Shen, Lingling; Yao, Qi; Tan, Xibin; Kang, Wenjun; Ma, Siyuan; Wu, Xiyan; Cai, Juntao; Gao, Mingxing; Li, Kang

2016-01-01

In this study, we proposed three optimized models for calculating the total volume of landslides triggered by the 2008 Wenchuan, China Mw 7.9 earthquake. First, we calculated the volume of each deposit of 1,415 landslides triggered by the quake based on pre- and post-quake DEMs in 20 m resolution. The samples were used to fit the conventional landslide “volume-area” power law relationship and the 3 optimized models we proposed, respectively. Two data fitting methods, i.e. log-transformed-based linear and original data-based nonlinear least square, were employed to the 4 models. Results show that original data-based nonlinear least square combining with an optimized model considering length, width, height, lithology, slope, peak ground acceleration, and slope aspect shows the best performance. This model was subsequently applied to the database of landslides triggered by the quake except for two largest ones with known volumes. It indicates that the total volume of the 196,007 landslides is about 1.2 × 1010 m3 in deposit materials and 1 × 1010 m3 in source areas, respectively. The result from the relationship of quake magnitude and entire landslide volume related to individual earthquake is much less than that from this study, which reminds us the necessity to update the power-law relationship. PMID:27404212

Optimized volume models of earthquake-triggered landslides.

PubMed

Xu, Chong; Xu, Xiwei; Shen, Lingling; Yao, Qi; Tan, Xibin; Kang, Wenjun; Ma, Siyuan; Wu, Xiyan; Cai, Juntao; Gao, Mingxing; Li, Kang

2016-07-12

In this study, we proposed three optimized models for calculating the total volume of landslides triggered by the 2008 Wenchuan, China Mw 7.9 earthquake. First, we calculated the volume of each deposit of 1,415 landslides triggered by the quake based on pre- and post-quake DEMs in 20 m resolution. The samples were used to fit the conventional landslide "volume-area" power law relationship and the 3 optimized models we proposed, respectively. Two data fitting methods, i.e. log-transformed-based linear and original data-based nonlinear least square, were employed to the 4 models. Results show that original data-based nonlinear least square combining with an optimized model considering length, width, height, lithology, slope, peak ground acceleration, and slope aspect shows the best performance. This model was subsequently applied to the database of landslides triggered by the quake except for two largest ones with known volumes. It indicates that the total volume of the 196,007 landslides is about 1.2 × 10(10) m(3) in deposit materials and 1 × 10(10) m(3) in source areas, respectively. The result from the relationship of quake magnitude and entire landslide volume related to individual earthquake is much less than that from this study, which reminds us the necessity to update the power-law relationship.

Landslide susceptibility mapping in three selected target zones in Afghanistan

NASA Astrophysics Data System (ADS)

Schwanghart, Wolfgang; Seegers, Joe; Zeilinger, Gerold

2015-04-01

In May 2014, a large and mobile landslide destroyed the village Ab Barek, a village in Badakshan Province, Afghanistan. The landslide caused several hundred fatalities and once again demonstrated the vulnerability of Afghanistan's population to extreme natural events following more than 30 years of civil war and violent conflict. Increasing the capacity of Afghanistan's population by strengthening the disaster preparedness and management of responsible government authorities and institutions is thus a major component of international cooperation and development strategies. Afghanistan is characterized by high relief and widely varying rock types that largely determine the spatial distribution as well as emplacement modes of mass movements. The major aim of our study is to characterize this variability by conducting a landslide susceptibility analysis in three selected target zones: Greater Kabul Area, Badakhshan Province and Takhar Province. We expand on an existing landslide database by mapping landforms diagnostic for landslides (e.g. head scarps, normal faults and tension cracks), and historical landslide scars and landslide deposits by visual interpretation of high-resolution satellite imagery. We conduct magnitude frequency analysis within subregional physiogeographic classes based on geological maps, climatological and topographic data to identify regional parameters influencing landslide magnitude and frequency. In addition, we prepare a landslide susceptibility map for each area using the Weight-of-Evidence model. Preliminary results show that the three selected target zones vastly differ in modes of landsliding. Low magnitude but frequent rockfall events are a major hazard in the Greater Kabul Area threatening buildings and infrastructure encroaching steep terrain in the city's outskirts. Mass movements in loess covered areas of Badakshan are characterized by medium to large magnitudes. This spatial variability of characteristic landslide magnitudes and

The landslide susceptibility mapping and assessment with ZY satellite data

NASA Astrophysics Data System (ADS)

Zhang, R.; Zhang, Z.; Zhao, Y.

2012-12-01

Natural hazards can result in enormous property damage and casualties in mountainous regions. In China, the direct loss of hazards is about 400 million yuan in 2011. Especially the landslide, the most common natural hazards, got the wide attention of each country. Landslide susceptibility mapping is of great importance for landslide hazard mitigation efforts throughout the world. In Southwest Hubei, there are much mineral mining activities, which may trigger the landslide. In addition the Three Gorges reservoir is located in this area, and the storage changed the geological and hydrological environment, which may increase the frequency of the ancient landslide reactivation, and the new landslide occurrence. There are more than 200 landslide hazards happened since 2003. So producing a regional-scaled landslide susceptibility map is necessary. For the above purpose, the landslide susceptibility mapping was produced by using the ZY-3 and ZY-1-02C satellite data, the DEMs and the conventional topographic data.(1) The DEM derivatives slope gradient, the slope aspect and the topographic wetness index (TWI) ; (2) in order to acquire the spatially continuous vegetation information, Normalized Difference Vegetation Index (NDVI) was computed using ZY-1-02C and ZY-3; (3) the regional lithologic information (i.e. mineral distribution) and the tectonic information obtained from remote sensing data in combination with regional geological survey; (4) the regional hydrogeological information was produced by using the remote sensing data in combination with the DEMs; (5) the existed landslides information obtained from remote sensing. To model the landslide hazard assessment using variety of statistic methods and evaluation methods, the cross application model yields reasonable results which can be applied for preliminary landslide hazard mapping and the hazard grade division.

Enriching Great Britain's National Landslide Database by searching newspaper archives

NASA Astrophysics Data System (ADS)

Taylor, Faith E.; Malamud, Bruce D.; Freeborough, Katy; Demeritt, David

2015-11-01

Our understanding of where landslide hazard and impact will be greatest is largely based on our knowledge of past events. Here, we present a method to supplement existing records of landslides in Great Britain by searching an electronic archive of regional newspapers. In Great Britain, the British Geological Survey (BGS) is responsible for updating and maintaining records of landslide events and their impacts in the National Landslide Database (NLD). The NLD contains records of more than 16,500 landslide events in Great Britain. Data sources for the NLD include field surveys, academic articles, grey literature, news, public reports and, since 2012, social media. We aim to supplement the richness of the NLD by (i) identifying additional landslide events, (ii) acting as an additional source of confirmation of events existing in the NLD and (iii) adding more detail to existing database entries. This is done by systematically searching the Nexis UK digital archive of 568 regional newspapers published in the UK. In this paper, we construct a robust Boolean search criterion by experimenting with landslide terminology for four training periods. We then apply this search to all articles published in 2006 and 2012. This resulted in the addition of 111 records of landslide events to the NLD over the 2 years investigated (2006 and 2012). We also find that we were able to obtain information about landslide impact for 60-90% of landslide events identified from newspaper articles. Spatial and temporal patterns of additional landslides identified from newspaper articles are broadly in line with those existing in the NLD, confirming that the NLD is a representative sample of landsliding in Great Britain. This method could now be applied to more time periods and/or other hazards to add richness to databases and thus improve our ability to forecast future events based on records of past events.

Modeling landslide recurrence in Seattle, Washington, USA

USGS Publications Warehouse

Salciarini, Diana; Godt, Jonathan W.; Savage, William Z.; Baum, Rex L.; Conversini, Pietro

2008-01-01

To manage the hazard associated with shallow landslides, decision makers need an understanding of where and when landslides may occur. A variety of approaches have been used to estimate the hazard from shallow, rainfall-triggered landslides, such as empirical rainfall threshold methods or probabilistic methods based on historical records. The wide availability of Geographic Information Systems (GIS) and digital topographic data has led to the development of analytic methods for landslide hazard estimation that couple steady-state hydrological models with slope stability calculations. Because these methods typically neglect the transient effects of infiltration on slope stability, results cannot be linked with historical or forecasted rainfall sequences. Estimates of the frequency of conditions likely to cause landslides are critical for quantitative risk and hazard assessments. We present results to demonstrate how a transient infiltration model coupled with an infinite slope stability calculation may be used to assess shallow landslide frequency in the City of Seattle, Washington, USA. A module called CRF (Critical RainFall) for estimating deterministic rainfall thresholds has been integrated in the TRIGRS (Transient Rainfall Infiltration and Grid-based Slope-Stability) model that combines a transient, one-dimensional analytic solution for pore-pressure response to rainfall infiltration with an infinite slope stability calculation. Input data for the extended model include topographic slope, colluvial thickness, initial water-table depth, material properties, and rainfall durations. This approach is combined with a statistical treatment of rainfall using a GEV (General Extreme Value) probabilistic distribution to produce maps showing the shallow landslide recurrence induced, on a spatially distributed basis, as a function of rainfall duration and hillslope characteristics.

Adjustment of the problems of landslide GIS data

NASA Astrophysics Data System (ADS)

Uchiyama, S.; Doshida, S.; Oyagi, N.; Shimizu, F.; Inokuchi, T.

2012-12-01

Information on the distribution of landslides is a basic type of data used by countries for disaster prevention. Since 1972, 1:50,000 landslide maps have been produced at the Japanese National Research Institute for Earth Science and Disaster Prevention. From October 2000, the institute has been producing landslide GIS data and transmitting these data over the web. The area that has been published so far covers over 80% of Japan. Presently, the number of diagrams printed are 980 (March 2012). In addition, 350,000 landslide GIS data graphs have been digitized with the same diagrams as a base. Twelve years have passed since this GIS data acquisition program was launched, and in that time, several problems have been identified. These problems are listed below. 1) Scarps do not become polygonized. 2) Landslides which extend over the boundaries of the printed graphs are divided into separate elements. 3) When the time taken to read and interpret the landslide data differs, the shape of the landslides can vary between diagrams. 4) There have been cases of inaccurate positions and shapes in landslide GIS data produced since 2005. 5) Obvious mistakes are present in the attribute data. The causes of such problems are as follows: 1) Lack of technical examination at the time of the start of the production of the landslide GIS data. 2) Limitations of the landslide GIS data editing systems which were developed separately. 3) Program bugs which occur during the conversion of information input to an individual editing system into general-purpose GIS data. 4) Problems which arise during the process of the production of landslide GIS data. This project at the National Research Institute for Earth Science and Disaster Prevention is planned to be completed in 2013. By the end of the project, we hope to present a catalogue of all identified problems and formulate a plan to resolve them, and pass them on to the next generation.; Problems: For the diagram, scarps are presented by

Analysis of Landslides Triggered by October 2005, Kashmir Earthquake

PubMed Central

Mahmood, Irfan; Qureshi, Shahid Nadeem; Tariq, Shahina; Atique, Luqman; Iqbal, Muhammad Farooq

2015-01-01

Introduction: The October 2005, Kashmir earthquake main event was triggered along the Balakot-Bagh Fault which runs from Bagh to Balakot, and caused more damages in and around these areas. Major landslides were activated during and after the earthquake inflicting large damages in the area, both in terms of infrastructure and casualties. These landslides were mainly attributed to the minimum threshold of the earthquake, geology of the area, climatologic and geomorphologic conditions, mudflows, widening of the roads without stability assessment, and heavy rainfall after the earthquake. These landslides were mainly rock and debris falls. Hattian Bala rock avalanche was largest landslide associated with the earthquake which completely destroyed a village and blocked the valley creating a lake. Discussion: The present study shows that the fault rupture and fault geometry have direct influence on the distribution of landslides and that along the rupture zone a high frequency band of landslides was triggered. There was an increase in number of landslides due to 2005 earthquake and its aftershocks and that most of earthquakes have occurred along faults, rivers and roads. It is observed that the stability of landslide mass is greatly influenced by amplitude, frequency and duration of earthquake induced ground motion. Most of the slope failures along the roads resulted from the alteration of these slopes during widening of the roads, and seepages during the rainy season immediately after the earthquake. Conclusion: Landslides occurred mostly along weakly cemented and indurated rocks, colluvial sand and cemented soils. It is also worth noting that fissures and ground crack which were induced by main and after shock are still present and they pose a major potential threat for future landslides in case of another earthquake activity or under extreme weather conditions. PMID:26366324

Analysis of Landslides Triggered by October 2005, Kashmir Earthquake.

PubMed

Mahmood, Irfan; Qureshi, Shahid Nadeem; Tariq, Shahina; Atique, Luqman; Iqbal, Muhammad Farooq

2015-08-26

The October 2005, Kashmir earthquake main event was triggered along the Balakot-Bagh Fault which runs from Bagh to Balakot, and caused more damages in and around these areas. Major landslides were activated during and after the earthquake inflicting large damages in the area, both in terms of infrastructure and casualties. These landslides were mainly attributed to the minimum threshold of the earthquake, geology of the area, climatologic and geomorphologic conditions, mudflows, widening of the roads without stability assessment, and heavy rainfall after the earthquake. These landslides were mainly rock and debris falls. Hattian Bala rock avalanche was largest landslide associated with the earthquake which completely destroyed a village and blocked the valley creating a lake. The present study shows that the fault rupture and fault geometry have direct influence on the distribution of landslides and that along the rupture zone a high frequency band of landslides was triggered. There was an increase in number of landslides due to 2005 earthquake and its aftershocks and that most of earthquakes have occurred along faults, rivers and roads. It is observed that the stability of landslide mass is greatly influenced by amplitude, frequency and duration of earthquake induced ground motion. Most of the slope failures along the roads resulted from the alteration of these slopes during widening of the roads, and seepages during the rainy season immediately after the earthquake.  Landslides occurred mostly along weakly cemented and indurated rocks, colluvial sand and cemented soils. It is also worth noting that fissures and ground crack which were induced by main and after shock are still present and they pose a major potential threat for future landslides in case of another earthquake activity or under extreme weather conditions.

Cyclic landsliding at Wrightwood, Southern California: a preliminary report

USGS Publications Warehouse

Morton, Douglas M.; Campbell, Russell H.

1978-01-01

Recurring landslide and mudflow events in the Wrightwood area of Southern California are parts of a composite cycle of landslide activity that includes three recognizable stages. The three stages are interdependent, occur in sequence, and are of different duration. Deposits of the first stage--the largest in size--are removed to positions further downstream by the activity of second- and third-stage landslides. First-stage landslides are represented by huge slumped masses derived from steep bedrock slopes in the canyon heads; the material moves down the principal stream drainage, which may be completely filled with debris. Second-stage activity develops as streams cut a network of branching channels into the massive first-stage deposit. The second-stage landslides are chiefly slumps from the older slide mass and from adjacent bedrock slopes. The movement of these slides generally is downslope toward actively eroding drainages. Third-stage activity includes mudflows that accompany the spring melting of snowpack. The debris moves down the stream channels to depositional reaches on major fans. Removal of sufficient amounts of the first-stage landslide mass to the fan by second- and third-stage events resets the bedrock slope of the main drainage for another first-stage event. The first-stage landslides in the Wrightwood area are of prehistoric origin, and their recurrence interval in any one canyon is probably several thousand years. The active duration of a first-stage landslide is one to several thousand years. Second-stage landslides last one to several years and are apparently preceded and triggered by a series of high-precipitation winters. The duration of observed third-stage (spring mudflow) sequences ranges from a few days to as much as six weeks; peak mudflow activity apparently results when a-heavy spring snowmelt occurs during a period of second-stage landslide activity.

Emergency response to landslide using GNSS measurements and UAV

NASA Astrophysics Data System (ADS)

Nikolakopoulos, Konstantinos G.; Koukouvelas, Ioannis K.

2017-10-01

Landslide monitoring can be performed using many different methods: Classical geotechnical measurements like inclinometer, topographical survey measurements with total stations or GNSS sensors and photogrammetric techniques using airphotos or high resolution satellite images. However all these methods are expensive or difficult to be developed immediately after the landslide triggering. In contrast airborne technology and especially the use of Unmanned Aerial Vehicles (UAVs) make response to landslide disaster easier as UAVs can be launched quickly in dangerous terrains and send data about the sliding areas to responders on the ground either as RGB images or as videos. In addition, the emergency response to landslide is critical for the further monitoring. For proper displacement identification all the above mentioned monitoring methods need a high resolution and a very accurate representation of the relief. The ideal solution for the accurate and quick mapping of a landslide is the combined use of UAV's photogrammetry and GNSS measurements. UAVs have started their development as expensive toys but they currently became a very valuable tool in large scale mapping of sliding areas. The purpose of this work is to demonstrate an effective solution for the initial landslide mapping immediately after the occurrence of the phenomenon and the possibility of the periodical assessment of the landslide. Three different landslide cases from Greece are presented in the current study. All three landslides have different characteristics: occurred in different geomorphologic environments, triggered by different causes and had different geologic bedrock. In all three cases we performed detailed GNSS measurements of the landslide area, we generated orthophotos as well as Digital Surface Models (DSMs) at an accuracy of less than +/-10 cm. Slide direction and velocity, mass balances as well as protection and mitigation measurements can be derived from the application of the UAVs

Soil and biomass carbon re-accumulation after landslide disturbances

NASA Astrophysics Data System (ADS)

Schomakers, Jasmin; Jien, Shih-Hao; Lee, Tsung-Yu; Huang-Chuan, Jr.; Hseu, Zeng-Yei; Lin, Zan Liang; Lee, Li-Chin; Hein, Thomas; Mentler, Axel; Zehetner, Franz

2017-07-01

In high-standing islands of the Western Pacific, typhoon-triggered landslides occasionally strip parts of the landscape of its vegetative cover and soil layer and export large amounts of biomass and soil organic carbon (OC) from land to the ocean. After such disturbances, new vegetation colonizes the landslide scars and OC starts to re-accumulate. In the subtropical mountains of Taiwan and in other parts of the world, bamboo (Bambusoideae) species may invade at a certain point in the succession of recovering landslide scars. Bamboo has a high potential for carbon sequestration because of its fast growth and dense rooting system. However, it is still largely unknown how these properties translate into soil OC re-accumulation rates after landslide disturbance. In this study, a chronosequence was established on four former landslide scars in the Central Mountain Range of Taiwan, ranging in age from 6 to 41 years post disturbance as determined by landslide mapping from remote sensing. The younger landslide scars were colonized by Miscanthus floridulus, while after approx. 15 to 20 years of succession, bamboo species (Phyllostachys) were dominating. Biomass and soil OC stocks were measured on the recovering landslide scars and compared to an undisturbed Cryptomeria japonica forest stand in the area. After initially slow re-vegetation, biomass carbon accumulated in Miscanthus stands with mean annual accretion rates of 2 ± 0.5 Mg C ha- 1 yr- 1. Biomass carbon continued to increase after bamboo invasion and reached 40% of that in the reference forest site after 41 years of landslide recovery. Soil OC accumulation rates were 2.0 Mg C ha- 1 yr- 1, 6 to 41 years post disturbance reaching 64% of the level in the reference forest. Our results from this in-situ study suggest that recovering landslide scars are strong carbon sinks once an initial lag period of vegetation re-establishment is overcome.

Broadband analysis of landslides seismic signal : example of the Oso-Steelhead landslide and other recent events

NASA Astrophysics Data System (ADS)

Hibert, C.; Stark, C. P.; Ekstrom, G.

2014-12-01

Landslide failures on the scale of mountains are spectacular, dangerous, and spontaneous, making direct observations hard to obtain. Measurement of their dynamic properties during runout is a high research priority, but a logistical and technical challenge. Seismology has begun to help in several important ways. Taking advantage of broadband seismic stations, recent advances now allow: (i) the seismic detection and location of large landslides in near-real-time, even for events in very remote areas that may have remain undetected, such as the 2014 Mt La Perouse supraglacial failure in Alaska; (ii) inversion of long-period waves generated by large landslides to yield an estimate of the forces imparted by the bulk accelerating mass; (iii) inference of the landslide mass, its center-of-mass velocity over time, and its trajectory.Key questions persist, such as: What can the short-period seismic data tell us about the high-frequency impacts taking place within the granular flow and along its boundaries with the underlying bedrock? And how does this seismicity relate to the bulk acceleration of the landslide and the long-period seismicity generated by it?Our recent work on the joint analysis of short- and long-period seismic signals generated by past and recent events, such as the Bingham Canyon Mine and the Oso-Steelhead landslides, provides new insights to tackle these issues. Qualitative comparison between short-period signal features and kinematic parameters inferred from long-period surface wave inversion helps to refine interpretation of the source dynamics and to understand the different mechanisms for the origin of the short-period wave radiation. Our new results also suggest that quantitative relationships can be derived from this joint analysis, in particular between the short-period seismic signal envelope and the inferred momentum of the center-of-mass. In the future, these quantitative relationships may help to constrain and calibrate parameters used in

Landslide in Aureum Chaos

NASA Technical Reports Server (NTRS)

2004-01-01

15 May 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the results of a small landslide off of a hillslope in the Aureum Chaos region of Mars. Mass movement occurred from right (the slope) to left (the lobate feature pointed left). Small dark dots in the landslide area are large boulders. This feature is located near 2.6oS, 24.5oW. This picture covers an area approximately 3 km (1.9 mi) across and is illuminated by sunlight from the left/upper left.

Rainfall-induced Landslide Susceptibility assessment at the Longnan county