Origin Of Landslides Research Articles

Statistical Analysis the Distribution of Landslide Triggered by m 8.0 Wenchuan, China Earthquake of May 12, 2008

Abundant landslides were triggered by Wenchuan earthquake. The paper mapped 4722 earthquake-induced landslides and used Geographic Information System to finish the statistical data about the occurrence of landslides correlating with environmental factors including distance from middle faults, lithology, altitude, river, and slope steepness. Because the seismic energy released along the middle faults and the attenuation of energy was obvious in minor axis, the zonal distribution of landslides was consistent with strike of middle faults and about 64.42% of landslides occurred within 20 km from middle faults of Longmenshan. As the middle faults and front faults both belonged to thrust faults, the impact of earthquake in hanging wall was higher than that in footwall. Therefore, the density of landslide in hanging wall of middle faults was obviously higher than that in footwall. As the release of seismic energy was restricted by landform and river, landslides were concentrative and consistent with the spatial distribution of rivers in the mountainous terrain. The scale effect of seismic acceleration was so intense in top of mountain with high difference in elevation along river that the origin of most landslides were in upside of slope. About 99.43% of landslides distributed in area where the seismic intensity was more than VII.

Landslides’ influence on the environment

In the area Bosnia, landslides on natural slopes are frequent occurrences that imperil some housing units, settlements, economic units and people's life or they imperil traffic safety on the roads, degrade agriculture and forest lands and they also lead to dislocation of surface and underground waters. The main causes of landslides' activation are changes in level of underground waters, chopping down of forest, great rainfalls, snow melting, long drought periods, changes in slopes, changes in load of a slope, rock's wastage, uncontrolled diversion of surface waters, earthquakes etc. Researches on landslides are carried out in order to establish the cause of landslide's origin and to find out efficient overhaul measures. Landslide's overhaul success depends not only on established causes of landslide's origin, but also on use of technical measures for stopping that process. Overhaul measures' carrying out is important in protection of the environment. This paper presents an analysis of co-action of natural factors and negative anthropogenic effect in a settled area, where landslides appear, by which studies and removing the causes are made conditions for the successful stabilization of landslides. The paper shows some characteristic landslides with defining of geomorphologic, geologic, engineer geologic, hydrogeologic and geotechnical characteristics of the terrain..

A Relict Pronival (Protalus) Rampart in the Tararua Range, North Island, New Zealand

ABSTRACTDebris ridges in New Zealand are routinely assumed to be ‘moraines’ and used as key Southern Hemisphere paleoclimatic sites without detailed evaluation of ridge origin. Here we assess the origin of a debris ridge adjacent to Dundas Ridge in the Tararua Range, North Island, New Zealand, through measurements of ridge morphology and sedimentary properties. The ridge has a steep c. 35° distal slope (height 18 m), compared with the c. 19° proximal slope (height 6 m), and on all transects the distal slopes contain the coarsest material (median b‐axis clast widths of 0.18‐0.25 m), compared to distal samples (0.34‐0.37 m). Clast shape (C40 range 40‐60%) and angularity (RA>65%) indicate typically angular and ‘slabby’ clasts, and along with the lack of fines, and the ca. 40‐m‐distance between the ridge crest and the foot of the backwall, lead us to reject a glacial (moraine) origin for the ridge. The single ridge morphology precludes a protalus rock glacier origin, while the lack of a broad hillslope scar and debris apron beyond the ridge excludes a landslide origin. Instead, we interpret the ridge as a pronival (protalus) rampart formed by supranival debris supply–from the ca. 200 m‐high southeastern slopes of Dundas Ridge–across a snowbed. Re‐distribution of snow by prevailing westerlies from Mt Dundas Ridge into the basin would have nourished the snowbed, which is likely to have formed during the interval 24‐18 ka BP, when a minor alpine‐style glaciation affected sectors of the Tararua Range. This is the first pronival rampart detailed in New Zealand, raising the possibility that debris ridges of pronival origin may also be present elsewhere in New Zealand's mountains. Copyright © 2012 John Wiley & Sons, Ltd.

The El Asnam 1980 October 10 inland earthquake: a new hypothesis of tsunami generation

SUMMARY The Western Mediterranean Sea is not considered as a high seismic region. Only several earthquakes with magnitude above five occur each year and only a handful have consequences on human beings and infrastructure. The El Asnam (Algeria) earthquake of 1980 October 10 with an estimated magnitude Ms= 7.3 is one of the most destructive earthquakes recorded in northern Africa and more largely in the Western Mediterranean Basin. Although it is located inland, it is known to have been followed by a small tsunami recorded on several tide gauges along the southeastern Spanish Coast. In 1954, a similar earthquake having occurred at the same location induced a turbidity current associated to a submarine landslide, which is widely known to have cut submarine phone cables far from the coast. This event was followed by a small tsunami attributed to the landslide. Thus the origin of the tsunami of 1980 was promptly attributed to the same kind of submarine slide. As no evidence of such mass movement was highlighted, and because the tsunami wave periods does not match with a landslide origin in both cases (1954 and 1980), this study considers two rupture scenarios, that the coseismic deformation itself (of about 10 cm off the Algerian coast near Tenes) is sufficient to produce a low amplitude (several centimetres) tsunami able to reach the Spanish southeastern coast from Alicante to Algeciras (Gibraltar strait to the west). After a discussion concerning the proposed rupture scenarios and their respective parameters, numerical tsunami modelling is performed on a set of bathymetric grids. Then the results of wave propagation and amplification (maximum wave height maps) are discussed, with a special attention to Alicante (Spain) Harbour where the location of two historical tide gauges allows the comparison between synthetic mareograms and historical records showing sufficient signal amplitude. This study is part of the active tsunami hazard assessment in Mediterranean Sea especially concerning its occidental part, that is, the Algerian, Spanish and French coasts.

Landslide-induced terminal moraine-like landforms on the east side of Mount Shiroumadake, Northern Japanese Alps

Previous studies have interpreted landforms east of Mount Shiroumadake (2932 m asl), in the Northern Japanese Alps, as lateral and terminal moraines and outwash terraces of glacial origin. However, recent studies in other areas of the Northern Japanese Alps have interpreted similar landforms as characteristic landslide bodies. We re-examined the origin and age of moraine-like landforms on the eastern side of Mount Shiroumadake through field geological surveys and landform analysis. We show that terminal moraine-like landforms in our study area consist of beds of brecciated or crushed gravel with locally derived crackle clasts and are unrepresentative of the variety of bedrock expose in the plausible source areas of Pleistocene glaciers. We interpret these deposits as induced by mass rock creep and landsliding at the terminus of a steep ridge or a steep valley side slope. Similarly, terrace surfaces formerly-interpreted as of outwash or fluvial origin consist of gravel beds with many fractured rock clasts of landslide origin. Although the timing of the landslides is not well constrained, they may have occurred in the early to middle Holocene. The highly deformed rocks of the study area, combined with the humid climate with much snowfall and rainfall, have left the landscape with an inherent predisposition for landsliding. Paleoearthquakes on nearby active faults in the piedmont area of Mount Shiroumadake may have provided a direct trigger for landsliding.

Unroofing history of Alabama and Poverty Hills basement blocks, Owens Valley, California, from apatite (U–Th)/He thermochronology

Most of the 150 km-long Owens Valley of east-central California, the westernmost graben of the Basin and Range Province and location of the active right-lateral Owens Valley Fault Zone, is filled with more than 2–3 km of Neogene sediments. Two prominent but structurally enigmatic basement blocks, the Alabama Hills and Poverty Hills, rise from the floor of the southern part of the valley. The late Cenozoic tectonic origin of these basement blocks is not known, but previously published hypotheses include: (1) transpressional uplifts; (2) down-dropped normal fault blocks; and (3) giant landslides from adjacent ranges. We measured apatite (U–Th)/He ages on 15 samples from the Alabama and Poverty Hills to understand the history of shallow crustal exhumation of these structures, and to potentially correlate them to rocks from adjacent ranges. Apatite He ages for the Alabama and Poverty Hills range from ∼63 to 52 and ∼61 to 39 Ma, respectively, with one sample from the Alabama Hills yielding an older weighted mean age of 79.3 ± 2.2 Ma (2σ). These ages are similar to those measured at elevations 1.5–3.0 km higher in both the adjacent Sierra Nevada and White/Inyo Mountains. Together with a lack of evidence for transpressional structures and the presence of extensive weathering of an ancient inherited surface on top of the Alabama Hills, these results are most consistent with an origin as a down-dropped normal fault block. A structural reconstruction using tilt-corrected southern Sierra Nevada age–elevation correlations requires 2.6 km of vertical and 1.5 km of eastward motion for the Alabama Hills along the Sierra Nevada Frontal Fault. Although we cannot conclusively rule out a landslide origin, our preferred explanation for the Poverty Hills data is that it is a down-dropped normal fault block that was transported from the Inyo Mountains along a right-lateral fault possessing a significant normal component.

Submarine landslide structures in neopleistocene deposits on the western slope of the Derbent basin of the Caspian Sea

In the autumn of 2004, during cruise 19 of R/V Rift, an “SES-2000 standard” super high-resolution narrow-beam parametric profiler was applied for studies of the fine structure of the uppermost sediments for the first time in the Caspian Sea. In this paper, we discuss the latitudinal seismoacoustic profile across the western slope of the Derbent Basin in the region of the Russian part of the Yalama-Samur hydrocarbon field. In the upper part of the slope, in the Neopleistocene deposits, a series of overthrust covers with a step-wise structure of displacement surfaces (duplexes) was revealed. They seem to have been formed by gravity processes. We also suggest the existence of a “pushed wedge” type of structure of landslide origin formed by the Bakinian-Khvalynian deposits intruding into the overlying Holocene sediments. Sufficiently distinct signs of disintegration of the bottom sediments and landslide-slumping processes were distinguished within the Eopleictocene deposits on the steepest lower part of the slope. The data of seismoacoustic profiling indicate that submarine landslide processes proceeded on the western slope of the Derbent Basin during the Neopleistocene-Holocene, which may have retained their activity up to present. These facts should be considered when designing engineering constructions over the Yalama-Samur structure.

The landslides in Bulgaria — factors and distribution

The necessity of contemporary assessment of the natural hazardous processes on the territory of Bulgaria leading to disastrous and catastrophic situations in a number of regions is motivated by their high activity resulting in destruction of building fund, infrastructure, historicalmonuments, land use disturbance and annihilation of areas, interrupting of communications, aggravation of ecological conditions, human health threats, social stress enhancement. The landslide manifestations displayed recently along the Black Sea coast and the Danubian riparian area, the Rhodopes and other parts of the country and their serious consequences confirm the long ago ascertained truth that the Bulgarian territory is characterized by a high degree of landslide hazard. The geological-tectonic conditions and the relief of the country determine the development of a large number of landslides on its territory. The many years of research and applied activities on landslides have led to the establishment of important relationships for their distribution, factors for origin and activation, mechanism and dynamics, etc. The origin and activation of landslides is a consequence of the influence of many factors — tectonic, seismic, geomorphologic, climatic and technogenic ones. A part of them act permanently, while others have short-term impact. Both separately and in combination they reduce slope stability and provoke the manifestation of big and destructive landslides. The impact of the destabilizing factors and the distribution of 403 landslides are analyzed in this work. Regions with different degree of landslide hazard have been distinguished. Diagrams are shown for the regional distribution and time of landslide display. The weighted effect of the destabilizing factors for slope stability formation is different. A part of them as the contemporary vertical movements and earthquakes are of regional importance, others act locally — erosion, abrasion, precipitation. The origin of the active landslides may be closely related to contemporary tectonic activity. The regional distribution of the landslides according to their volume shows that landslides with a volume up to 10 million m3 are the prevailing type in the country. The most numerous landslides in this group — about 50% of the total number — are observed along high Danubean Bank and Northern Black Sea coast, in the tectonically active grabens as Sofia, Pernik or Simitli and the landslides along some of the faults in the Strouma zone. The largest landslides with a volume of more than 100 million m3 are encountered along the Danubean Bank, the Northern Black Sea coast and in Rhodope Region.

The origin of shallow landslides in Moravia (Czech Republic) in the spring of 2006

At the end of March 2006, the Czech Republic (CZ) witnessed a fast thawing of an unusually thick snow cover in conjunction with massive rainfall. Most watercourses suffered floods, and more than 90 shallow landslides occurred in the Moravian region of Eastern CZ, primarily in non-forested areas. This region, geologically part of the Outer Western Carpathians, is prone to landslides because the bedrock is highly erodible Mesozoic and Tertiary flysch. The available meteorological data (depth of snow, water equivalent of the snow, cumulative rainfall, air and soil temperatures) from five local weather stations were used to construct indices quantitatively describing the snow thaw. Among these, the Total Cumulative Precipitation ( TCP) combines the amount of water from both thawing snow and rainfall. This concurrence of rain and runoff from snow melt was the decisive factor in triggering the landslides in the spring. The TCP index was applied to data of snow thaw periods for the last 20 years, when no landslides were recorded. This was to establish the safe threshold of TCP without landslides. The calculated safe threshold value for the region is ca. 100 mm of water delivered to the soil during the spring thaw (corresponding to ca. 11 mm day − 1 ). In 2006, 10% of the landslides occurred under or at 100 mm of TCP. The upper value of 155 mm covered all of the landslides.

Cold‐climate modification of Martian landscapes: A case study of a spatulate debris landform in the Hellas Montes Region, Mars

We use spaceborne image and topographic data of Mars for a geomorphological study of the origin, development, and postemplacement modification of a 30‐km‐long spatulate landform in the Hellas Montes area, east of Hellas Planitia. The area is characterized by an abundance of lobate debris aprons, all of which have been interpreted as a result of creep and viscous deformation of rock and ice mixtures that make the eastern Hellas Planitia assemblages a type location for possible Martian rock glaciers. The spatulate landform has been discussed controversially in the past. Explanations range from a rock glacier to a wet debris avalanche or debris flow origin. This work scrutinizes arguments provided in earlier works and presents evidence that a landslide origin of the spatulate landform, connected with a sector collapse of a volcanic construct, is conceivable. We also find extensive observational evidence that the landslide has recently undergone or is still undergoing significant postemplacement modifications, which are characteristic of rock glaciers in periglacial environments. Creep deformation as well as disintegration of the original surface by thermokarstic degradation is considered to have obliterated impact craters and, in consequence, create a seemingly younger age. Similar processes are considered to be common on Mars under current climatic conditions. Our results imply that the strong and possible long‐term modification of landforms on Mars by cold‐climate processes often hinders the identification of their original nature and complicates the assessment of true ages.

New observations of volcanic features on Mars from the THEMIS instrument

Images obtained by the THEMIS instrument on Mars Odyssey permit the identification of many new volcanic features on Mars. Several new types of vent systems, including fissure vents within the Tharsis region, flank vents on Olympus Mons and Ascraeus Mons, and lava shields on the floor of Arsia Mons have been found. The valley networks on Hecates Tholus are seen to be more complex than previously believed. Extending from the caldera rim to the base of Hecates Tholus volcano, individual valleys change width and depth in apparent response to local topography. Valley formation spanned the time period during which lava flows from Elysium Mons embayed the southern flank of Hecates Tholus, as demonstrated by the burial of some valleys by the lava flows and the formation of sediment fans on top of adjacent parts of the flows. THEMIS images now allow new constraints to be placed on the dynamics of lava flow emplacement, with the identification of flows with well‐defined lava channels on the northern flank of Ascraeus Mons, as well as an enigmatic braided lava channel. Three previously unreported collapse events (3.7 to 4.3 km in diameter) are identified within the caldera of Ascraeus Mons. Details of the mode of formation of parts of the Olympus Mons aureole can also be identified, supporting the idea that the aureole had a landslide origin. THEMIS images show that parts of the aureole have been modified by water discharged to the east of Olympus Mons.

A geomorphological assessment of landslide origin at Bukavu, Democratic Republic of the Congo

Bukavu, on the south coast of Lake Kivu in the Democratic Republic of the Congo, suffers from slow but never ending landsliding. This leads to the continuous degradation and destruction of houses, buildings and of the roads, waterworks and sewerage infrastructure in several districts of the town. Research of mass-wasting processes is hampered by the limited geotechnical and hydrogeological information concerning the deeply weathered Tertiary and Quaternary lavas. There is also a disagreement about the exact location of active faults, believed to play a role in the mass wasting. Additionally, there is little information about the exact location and the rate of soil movements and whether ground instability is caused by tectonics and seismics or by increase in hydrostatic pressure. Based on aerial photographic interpretation, landslides cover more than 15% of the town of Bukavu. Thirty-one landslides occur outside the Bukavu “microrift” and do not contact active faults. Rather, they occur in actively incising river basins, ostensibly caused by neotectonic activity. Four from the six landslides within the “micrograben” are bigger and wider than the others, apparently governed by pre-existing tectonically induced landforms. They are adjacent to or crossed by active faults. They also fall far below the envelope of topographic thresholds for landslides established for North America and verified in Rwanda. Therefore, this threshold, a combination of slope at the head of the slide and surface drained to it, seems a promising tool to discriminate hydrologically from tectonically seismically induced landslides. Recent soil movements in Bukavu generally correspond to landslide distribution portrayed on the geomorphologic map. Most Bukavu soil movements occur on previous slides. Therefore, from an engineering–geologic standpoint, old landslides should be avoided, or, if economically feasible, be mitigated.

Slope evolution Processes of Landslides around the Quaternary Volcanoes in the Tohoku district, Japan.

Slope evolution processes of landslides around the Quaternary volcanoes have been studied in the surrounding area of the Hijiori caldera in the Central Tohoku district, Japan. These landslides are located on the cuesta or crest slopes composed of Tertiary mudstone/sandstone layers overlaid by pyroclastic flow deposits that have been dissected at the toe and side part of the slopes. They are slipping along the bedding plane. They originated from the primary rockslides just before the deposition of pyroclastic flow from the caldera.The evolution processes of the Hirane landslide, 5km north from the Hijiori caldera were studied from the slope stability calculation both by the Fellenius and the simplified Janbu three-dimensional methods (Ukai, 1987). Though an earthquake with more than 700 gal can induce a landslide, it is indicated that the primary rockslide could occur in the mudstone layers by the earthquake with 300-500 gal at the eruption time of the pyroclastic flow. Weakening of the rocks by pre-eruption earthquakes and the location of the landslides on the crest of cuesta slopes might have been the cause.Just after this slide, the slope had been buried by the thick pyroclastic flow deposits and got higher stability. Continuous erosion of the pyroclastic flow deposits from the toe part of the landslide slopes has induced the instability of the primary rockslide. Stability calculation by using the residual shear strength obtained from ring shear tests indicates present unstable condition of the landslide. The slope evolution processes mentioned above could be applied to the origin of the other present large-scale landslides around the Quaternary volcanoes in the Tohoku district.

Landslide development in a coastal valley in Northern Spain: conditioning factors and temporal occurrence

Sixty-five landslides have been mapped in the Meredal Valley, carved in one of the Asturian Precoastal Ranges on Mesozoic bedrock. From a genetic point of view, two groups of landslides can be distinguished: landslides developed mainly over Triassic lutites (complex movements, flows and rockslides) and landslides developed from calcareous cliffs (rock avalanches). Many of them are relict landslides, although evidence of activity can be recognized, as a result of a partial reactivation of some of the landslides. Four chronological classes have been established according to geomorphological criteria and the degree of preservation of the landslides. A lateral plugging deposit provides a minimum age of 5050±40 B.P. for the oldest class. In the same way, a stalactite gives to the third class of landslides a minimum age of 3392±128 B.P. The origin of landslides can be related to the plastic behavior of lutite and the permeability of the overlying limestone, which allows vertical seepage of water. From a regional point of view, landslides could be connected with Quaternary fluvial incision processes, as well as to Holocene high rainfall events.

Tectonic predesign of mass movements, with examples from the Chinese Himalaya

The genesis of landslides has traditionally been ascribed essentially to exogenic, nontectonic causes. Thus, it has generally been assumed that progressive erosion oversteepens slopes until they become unstable and collapse by forming slides; the specific triggers in each case would be exogenic influences such as, for instance, an extreme weather period. This paper shows that in practically all cases of mass-movements, endogenic processes are also of fundamental importance. In the first place, a landscape responds as a complex open system existing in a quasi-stationary state at the edge of chaos in which an endogenic input and exogenic outflow of mass and energy occur; this quasi-stationary state can become unstable resulting in landslides. In the second place, a direct predesign is present because of endogenic causes, viz. by a former or the present geotectonic stress field. Thus, some common notable contentions regarding the origin of landslides are shown to be false. A better understanding of the mechanisms for landslide genesis is illuminated using examples from the Chinese mountain ranges at the east end of the Himalayas. In these particular cases, the orientations of mass movements are directly controlled (`predesigned') by the present-day local tectonic stress.

A giant landslide on the north flank of Tenerife, Canary Islands

The extent of mass wasting along the north flank of Tenerife has been mapped using swath bathymetry, GLORIA side‐scan sonar, and 3.5‐kHz echo sounder data. The marine surveys show that, north of Tenerife, a giant landslide is exposed over an area of 5500 km2 of the seafloor, more than twice the surface area of the island. The landslide truncates an older ridge and valley topography that is associated with the shield building basalts on Tenerife. We interpret the ridge and valley topography as the result of subaerial erosion. The landslide is estimated to have a length of 100 km, a width of up to 80 km, and a volume of about 1000 km3. It extends onshore into the Orotava and Icod valleys which have been interpreted as of landslide origin. K‐Ar dating of basaltic flows in the steep headwall of Orotava suggests an age of formation for the valley is younger than 0.78 Ma and may even be younger than 0.27 Ma. The Icod valley is located immediately to the north of the most recent volcano on Tenerife, Las Cañadas, and has been associated with the collapse of its caldera, between 1.2 and 0.2 Ma. A young age for the landslide is supported by the 3.5‐kHz echo sounder data which show that the landslide is draped by a thin (< 10 m) layer of younger sediment. The landslide did not form, however, during a single catastrophic event but represents the amalgamation of a number of separate landslides. The occurrence of the ridge and valley topography in water depths of up to 2.5 km suggests that the shield‐building basalts have subsided by at least this amount since they formed, 3.3–8.0 Ma. We speculate that this subsidence is caused by some form of stress relaxation that occurs in the underlying lithosphere. The giant landslide imaged in our sonar data is associated with the late stages in the development of the most recent volcano on Tenerife, Las Canadas, which only began at about 1.8 Ma. Thus landsliding may be a particular feature of the time soon after emplacement when because of incomplete isostatic adjustment, oceanic volcanoes have their greatest elevations above sea‐level and therefore are most susceptible to slope failure.

Analysis of the origin of landslides in the New Madrid seismic zone: R. W. Jibson & D. K. Keefer, US Geological Survey Professional Paper, 1538(D), 1994, 23 pp

Dl Introduction 1 Geologic Setting 2 Seismic History 3 Description of Landslides in the Area 3 Previous Work 4 Analysis of the Stewart and Campbell Landslides 5 Geotechnical Investigation 7 Static (Aseismic) Slope Stability Analysis 8 Idealized Pre-Landslide Bluff Model 8 Ground-Water Conditions 8 Method of Stability Analysis 9 Results of Static Slope Stability Analysis 10 Dynamic (Seismic) Slope Stability Analysis 11 Factor of Safety 12 Thrust Angle 14 Earthquake Acceleration-Time History 15 Calculation of the Newmark Landslide Displacement 17 Results of Dynamic Analysis of Stewart Landslide 18 Results of Dynamic Analysis of Campbell Landslide 18 Summary of Stability Analyses 18 What if Seismic Conditions Are Unknown? 18 Discussion 20 Summary and Conclusions 21 References Cited 22

1906 surface faulting on the San Andreas fault near Point Delgada, California

The northernmost onshore surface faulting on the San Andreas fault in 1906 was reported at Shelter Cove, a small embayment in the coastline east of Point Delgada. Between 1979 and 1985, several authors questioned both this location for the San Andreas fault and the validity of 1906 surface faulting. Alternatively, they proposed an offshore fault and a landslide origin for the 1906 ground fractures. F. E. Matthes (1874-1948) described and mapped the surface deformation at Shelter Cove in May and June 1906, documenting evidence of surface faulting for about 3 km between Dead Mans Gulch and Kaluna Cliff. Detailed sketch maps in his notebook indicate a component of right-lateral strike slip and a consistent fault dip to the southwest. Geomorphic and geologic evidence confirm a right-oblique sense of slip and a southwest dip of about 45°; the projected trace of the fault meets the sea at a point about 1.5 km northwest of Kaluna Cliff. Aligned scarps, saddles, and deflected stream courses along this fault imply repeated, nearly colinear, fault displacements during late Quaternary time. Published observations of shear strain and fission-track ages show that a narrow (<1 km) zone containing the mapped fault trace is slipping at depth in a right-lateral sense and is also a profound tectonic boundary separating rocks with different thermal histories. Collectively, the evidence supports both the reported faulting in 1906 and the interpretation that this fault is a northern extension of the San Andreas fault.

Analysis of the seismic origin of landslides: examples from the New Madrid seismic zone : Jibson, R W; Keeper, D K Bull Geol Soc AmV105, N4, April 1993, P521–536

Analysis of the seismic origin of landslides: examples from the New Madrid seismic zone : Jibson, R W; Keeper, D K Bull Geol Soc AmV105, N4, April 1993, P521–536

Analysis of the seismic origin of landslides: Examples from the New Madrid seismic zone

Research Article| April 01, 1993 Analysis of the seismic origin of landslides: Examples from the New Madrid seismic zone RANDALL W. JIBSON; RANDALL W. JIBSON 1U.S. Geological Survey, Box 25046, M.S. 966, Denver Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar DAVID K. KEEFER DAVID K. KEEFER 2U.S. Geological Survey, 345 Middlefield Road, M.S. 998, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Author and Article Information RANDALL W. JIBSON 1U.S. Geological Survey, Box 25046, M.S. 966, Denver Federal Center, Denver, Colorado 80225 DAVID K. KEEFER 2U.S. Geological Survey, 345 Middlefield Road, M.S. 998, Menlo Park, California 94025 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1993) 105 (4): 521–536. https://doi.org/10.1130/0016-7606(1993)105<0521:AOTSOO>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation RANDALL W. JIBSON, DAVID K. KEEFER; Analysis of the seismic origin of landslides: Examples from the New Madrid seismic zone. GSA Bulletin 1993;; 105 (4): 521–536. doi: https://doi.org/10.1130/0016-7606(1993)105<0521:AOTSOO>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract By analyzing two landslides in the New Madrid seismic zone, we develop an approach for judging if a landslide or group of landslides of unknown origin was more likely to have formed as a result of earthquake shaking or in aseismic conditions. The two landslides analyzed are representative of two groups of land-slides that previous research on the geomorphology and regional distribution of landslides in this region indicates may have been triggered by the 1811-1812 New Madrid earthquakes. Slope-stability models of aseismic conditions show that neither landslide is likely to have formed aseismically even in unrealistically high ground-water conditions. Dynamic stability analysis using Newmark's method shows that both slides probably would have experienced large inertial displacements during earthquake shaking similar to that which occurred in 1811-1812; these displacements are large enough that catastrophic failure is highly probable. Thus, the stability analyses are consistent with other lines of evidence that these landslides formed as a result of strong earthquake shaking during the 1811-1812 earthquakes.Our analysis yields a general relationship between Newmark landslide displacement, earthquake shaking intensity, and the critical acceleration of a landslide. Using this relationship, we estimate the minimum shaking intensities required to trigger the types of landslides studied: an mb = 5.8 or M = 5.9 earthquake is the lower bound threshold at zero epicentral distance that could trigger catastrophic movement of typical block slides in the New Madrid seismic zone; for earth flows, mb = 5.4 or M = 5.3 is the threshold earthquake. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.