Slope failures associated with the 1988 Saguenay earthquake, Quebec, Canada

1992 ◽  
Vol 29 (1) ◽  
pp. 117-130 ◽  
Author(s):  
Guy Lefebvre ◽  
Denis Leboeuf ◽  
Pierre Hornych ◽  
Luc Tanguay
Keyword(s):  
Granular Material ◽  
Key Words ◽  
Slope Failure ◽  
Failure Surface ◽  
Slope Failures ◽  
Clay Deposits ◽  
Sensitive Clay ◽  
Static Conditions ◽  
Undrained Loading ◽  
Natural Slopes

Nine case records of slope failure during the Saguenay earthquake are documented, including five in granular embankments, two in natural slopes in granular material with small embankments at the top, and two in sensitive clay. The bedrock motion during the earthquake is well documented; each failure is related to the most probable bedrock motion at the site (0.05 to 0.15 g). For the seven cases of failure in granular slopes, the reserve of stability under static conditions was relatively low before the earthquake, and only a small additional undrained loading was necessary to develop failure. Two slope failures occurred in extrasensitive clay deposits containing no visible lens or layer of silt or sand. Silty or sandy materials have been identified only at the clay–till contact. It is believed that in at least one of the sites a portion of the failure surface developed at the inclined clay–till contact. Key words : slope failure, earthquake, sensitive clays, embankment fill, stability, granular material.

scholarly journals Structure and dynamics of deep-seated slope failures in the Magura Flysch Nappe, outer Western Carpathians (Czech Republic)

2004 ◽  
Vol 4 (4) ◽  
pp. 549-562 ◽  
Author(s):  
I. Baron ◽  
V. Cilek ◽  
O. Krejci ◽  
R. Melichar ◽  
F. Hubatka
Keyword(s):  
Czech Republic ◽  
Slope Failure ◽  
Interdisciplinary Approach ◽  
Failure Surface ◽  
Late Glacial ◽  
Western Carpathians ◽  
Mass Movements ◽  
Slope Failures ◽  
Total Displacement ◽  
Outer Western Carpathians

Abstract. Deep-seated mass movements currently comprise one of the main morphogenetic processes in the Flysch Belt of the Western Carpathians of Central Europe. These mass movements result in a large spectrum of slope failures, depending on the type of movement and the nature of the bedrock. This paper presents the results of a detailed survey and reconstruction of three distinct deep-seated slope failures in the Raca Unit of the Magura Nappe, Flysch Belt of the Western Carpathians in the Czech Republic. An interdisciplinary approach has enabled a global view of the dynamics and development of these deep-seated slope failures. The three cases considered here have revealed a complex, poly-phase development of slope failure. They are deep-seated ones with depths to the failure surface ranging from 50 to 110m. They differ in mechanism of movement, failure structure, current activity, and total displacement. The main factors influencing their development have been flysch-bedrock structure, lithology, faulting by bedrock separation (which enabled further weakening through deep weathering), geomorphic setting, swelling of smectite-rich clays, and finally heavy rainfall. All of the slope failures considered here seem to have originated during humid phases of the Holocene or during the Late Glacial.

scholarly journals The evolution of slope failures: mechanisms of rupture propagation

2004 ◽  
Vol 4 (1) ◽  
pp. 147-152 ◽  
Author(s):  
D. N. Petley
Keyword(s):  
Slope Failure ◽  
Complex Stress ◽  
Basal Region ◽  
Rupture Propagation ◽  
Slope Failures ◽  
Stress Regime ◽  
Detailed Surface ◽  
Landslide Mass ◽  
Region Data ◽  
Detailed Assessment

Abstract. Forecasting the occurrence of large, catastrophic slope failures remains very problematic. It is clear that in order advance this field a greater understanding is needed of the processes through which failure occurs. In particular, there is a need to comprehend the processes through which a rupture develops and propagates through the slope, and the nature of the inter-relationship between the stress and strain states of the landslide mass. To this end, a detailed analysis has been undertaken of the movement records for the Selborme Cutting slope failure, in which failure was deliberately triggered through pore pressure elevation. The data demonstrate that it is possible to determine the processes occurring in the basal region of the landslide, and thus controlling the movement of the mass, from the surface movement patterns. In particular, it is clear that the process of rupture development and propagation has a unique signature, allowing the development of the rupture to be traced from detailed surface monitoring. For landslides undergoing first time failure through rupture propagation, this allows the prediction of the time of failure as per the "Saito" approach. It is shown that for such predictions to be reliable, data from a number of points across the landslide mass are needed. Interestingly, due to the complex stress regime in that region, data from the crown may not be appropriate for failure prediction. Based upon these results, the application of new techniques for the detailed assessment of spatial patterns of the development of strain may potentially allow a new insight into the development of rupture surfaces and may ultimately permit forecasting of the temporal occurrence of failure.

Recurrent rock avalanches progressively dismantle mountain ridges in the Longmen Shan, China, most recently in the 2008 Wenchuan earthquake

2021 ◽  
Author(s):  
Janusz Wasowski ◽  
Maurice McSaveney ◽  
Luca Pisanu ◽  
Vincenzo Del Gaudio ◽  
Yan Li ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Ambient Noise ◽  
Slope Failure ◽  
Mass Movement ◽  
Rock Avalanche ◽  
Ground Vibration ◽  
Source Area ◽  
Slope Failures ◽  
Rock Avalanches ◽  
Beichuan County

<p>Large earthquake-triggered landslides, in particular rock avalanches, can have catastrophic consequences. However, the recognition of slopes prone to such failures remains difficult, because slope-specific seismic response depends on many factors including local topography, landforms, structure and internal geology. We address these issues by exploring the case of a rock avalanche of >3 million m<sup>3</sup> triggered by the 2008 Mw7.9 Wenchuan earthquake in the Longmen Shan range, China. The failure, denominated Yangjia gully rock avalanche, occurred in Beichuan County (Sichuan Province), one of the areas that suffered the highest shaking intensity and death toll caused by co-seismic landsliding. Even though the Wenchuan earthquake produced tens of large (volume >1 million m<sup>3</sup>) rock avalanches, few studies so far have examined the pre-2008 history of the failed slope or reported on the stratigraphic record of mass-movement deposits exposed along local river courses. The presented case of the Yangjia gully rock avalanche shows the importance of such attempts as they provide information on the recurrence of large slope failures and their associated hazards. Our effort stems from recognition, on 2005 satellite imagery, of topography and morphology indicative of a large, apparently pre-historic slope failure and the associated breached landslide dam, both features closely resembling the forms generated in the catastrophic 2008 earthquake. The follow-up reconstruction recognizes an earlier landslide deposit exhumed from beneath the 2008 Yangjia gully rock avalanche by fluvial erosion since May 2008. We infer a seismic trigger also for the pre-2008 rock avalanche based on the following circumstantial evidence: i) the same source area (valley-facing, terminal portion of a flat-topped, elongated mountain ridge) located within one and a half kilometer of the seismically active Beichuan fault; ii) significant directional amplification of ground vibration, sub-parallel to the failed slope direction, detected via ambient noise measurements on the ridge adjacent to the source area of the 2008 rock avalanche and iii) common depositional and textural features of the two landslide deposits. Then, we show how, through consideration of the broader geomorphic and seismo-tectonic contexts, one can gain insight into the spatial and temporal recurrence of catastrophic slope failures  in Beichuan County and elsewhere in the Longmen Shan. This insight, combined with local-scale geologic and geomorphologic knowledge, may guide selection of suspect slopes for reconnaissance, wide-area ambient noise investigation aimed at discriminating their relative susceptibility to co-seismic catastrophic failures. We indicate the feasibility of such investigations through the example of this study, which uses 3-component velocimeters designed to register low amplitude ground vibration.</p>

Investigating the controls of submarine landslides and associated hazards in Pangnirtung Fiord, Eastern Baffin Island (Nunavut)

2021 ◽  
Author(s):  
Philip Sedore ◽  
Alexandre Normandeau ◽  
Vittorio Maselli
Keyword(s):  
High Latitude ◽  
Debris Flows ◽  
Slope Failure ◽  
Recurrence Time ◽  
High Recurrence Rate ◽  
Baffin Island ◽  
Submarine Landslides ◽  
Slope Failures ◽  
Near Surface ◽  
Submarine Slope

<p>High-latitude fiords are susceptible to hazardous subaerial and submarine slope failures. Recent investigations have shown that past slope failures in fiords of Greenland and Alaska have generated devastating landslide induced tsunamis. Since coastal communities inhabit these high-latitude fiords, it is critical to understand the slope failure recurrence time, their distribution, potential triggers, and ability to generate tsunamis. In this study, we identified > 50 near-surface submarine landslides in Pangnirtung Fiord, eastern Baffin Island, Nunavut, using multibeam bathymetric and sub-bottom profiler data, along with sediment gravity-cores collected in 2019. Morphometric and morphological analyses, along with sedimentological analyses, were carried out on submarine landslide deposits to quantify their spatial and temporal distribution throughout the fiord and to evaluate the factors that may have triggered the slope failures.</p><p>Combining bathymetric with topographic data from unmanned aerial vehicle imagery, we found that most of these landslide deposits are relatively small (~ 0.08 km<sup>2</sup>) and are associated with outwash fans and steep fiord sidewalls. However, since most slope failure head scarps lie between the intertidal zone and ~30 m water depth, they could not be mapped, which makes it challenging to determine the triggers of the submarine slope failures. Radiocarbon dating reveals that most of these surficial landslide deposits are younger than 500 years old and that they were most likely triggered at different times. This finding highlights a high recurrence rate of slope failures within the fiord, suggesting that localised triggers are responsible for slope failures within the fiord, as opposed to widespread, seismically induced triggers which do not occur as frequently in the study area. In addition, the elongated morphology of the landslide deposits and the varying degrees of landslide deposit surface roughness supports localised point-source triggers. Since most landslides are associated with subaerial outwash fans and deltas, we suggest that triggers of these relatively frequent submarine landslides within Pangnirtung Fiord include rapid floodwater input, subaerial debris flows, and sea-ice loading during low tide.</p><p>This research shows that slope failures in a high-latitude fiord are affected by the interaction of numerous subaerial and submarine processes, leading us to speculate that a potential increase in the frequency of subaerial debris flows and river floods due to climate change may increase the recurrence of submarine landslides.<strong> </strong></p>

Assessment of Guar Gum Biopolymer Treatment toward Mitigation of Desiccation Cracking on Slopes Built with Expansive Soils

2017 ◽  
Vol 2657 (1) ◽  
pp. 78-88 ◽  
Author(s):  
Raju Acharya ◽  
Aravind Pedarla ◽  
Tejo V. Bheemasetti ◽  
Anand J. Puppala
Keyword(s):  
Factor Of Safety ◽  
Slope Failure ◽  
Soil Stabilization ◽  
Guar Gum ◽  
Expansive Soils ◽  
Environmental Benefits ◽  
Three Dimensions ◽  
Slope Failures ◽  
Lagrangian Analysis ◽  
Desiccation Cracking

Expansive soil embankments are prone to shallow slope failures caused by associated swell–shrink movements. Previous studies have confirmed that seasonal changes and corresponding volumetric changes are responsible for desiccation cracking, which is a major factor behind shallow slope failures of highway embankments. For the past few years, soil stabilization proved to be an effective way to mitigate the swell–shrink property of expansive clays. The current study addresses the feasibility of guar gum biopolymer in mitigating the swell–shrink behavior of clays and in turn making it possible to adopt them as stable geomaterials. The sustainable benefits of biopolymers far exceed the environmental benefits from conventional stabilizers that contractors typically use. This paper presents a comprehensive laboratory study, followed by finite difference modeling analysis, on biopolymeric guar gum–remediated expansive soils collected from shallow slope failure-prone areas. For this study, two dam locations, at Grapevine Lake and Joe Pool Lake, Texas, that were originally constructed with expansive soils, were considered. The engineering performance of biopolymer-treated soils was evaluated and an optimum dosage was recommended for mitigating desiccation cracking at the test sites. Slope stability analyses were conducted using Fast Lagrangian Analysis of Continua in Three Dimensions software by adopting laboratory-determined strength parameters to determine the range of the factor of safety for the slopes. The variation of the factor of safety computed with the inclusion of enhanced engineering parameters from guar gum treatments revealed the advantages of adopting this treatment.

Fracturing within anticlines and its kinematic control on slope stability

2002 ◽  
Vol 8 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Thomas C. Badger
Keyword(s):  
Slope Stability ◽  
Ground Water ◽  
Slope Failure ◽  
Mode I ◽  
Mode Ii ◽  
Shear Stresses ◽  
Fold Axis ◽  
Slope Failures ◽  
Kinematic Control ◽  
Discontinuity Sets

Abstract Anticlinal folding generates both bedding-parallel shear stresses and tensional stresses radial to the fold axis. These stresses typically produce two sets of discontinuities. Discontinuity set S 1 forms coincident with bedding (S 0 ) as a mode II fracture, and discontinuity set S 2 forms perpendicular to bedding and strikes parallel to the fold axis as a mode I fracture. For slopes that strike parallel to the fold axis, these two discontinuity sets may produce three structurally-controlled modes of slope failure. For slopes that are coincident with bedding, planar failures along S 0 /S 1 commonly occur and can be very large. Where bedding dips favorably into the slope, failures along joint set S 2 and across bedding can occur. Toppling failures are common to both of these slope configurations, along S 2 and S 0 /S 1 , respectively. Lastly, flat or shallow dipping S 0 /S 1 fractures, even those favorably oriented, and intersecting S 2 joints define blocks that can be mobilized by high ground-water pressures. An example is presented for each slope configuration to illustrate these kinematic controls on slope stability.

Development and ultrastructure of the haustorium of Viscum minimum. I. The adhesive disk

1989 ◽  
Vol 67 (4) ◽  
pp. 1161-1173 ◽  
Author(s):  
H. S. Heide-Jørgensen
Keyword(s):  
Granular Material ◽  
Key Words ◽  
Secretory Cell ◽  
The Future ◽  
Different Ages ◽  
Adhesive Disk ◽  
Cuticular Layer ◽  
Cuticle Ultrastructure

The adhesive disk of the haustorium of Viscum minimum Harvey develops an epithelium of uni- or bi-cellular secretory trichomes. Before contact with the host is obtained, the trichomes secrete adhesive cutinaceous material. This secretion contains fragments of the lamellar cuticle proper, the reticulate cuticular layer, and the noncutinized part of the cuticularized wall, in additions to pockets of granular material. The volume of the adhesive product per trichome may be several times the volume of the secretory cell itself except in front of the future intrusive organ where secretion is reduced. Formation of cutin cystoliths was observed in sections of wall of different ages within single trichomes. The trichomes are rich in mitochondria, plastids with starch, spherosomes, ribosomes, and ER that are associated with the strongly convoluted plasmalemma. A special type of tubular ER is described. Zones of collapsed cells are formed in the cortex as the apex of the wedge-shaped intrusive organ emerges. The cuticularized wall of the host then disintegrates, and the intrusive organ forms a fissure within the host. This becomes lined, to the depth of a few cells, partly with cuticularized and finally compressed cells originating from the adhesive epithelium, and partly with new cells produced by the intrusive organ. Key words: Viscum minimum, adhesive disk, adhesive epithelium, cuticle ultrastructure, cutin cystolith, haustorium, secretion.

EARTHQUAKE-TRIGGERED LANDSLIDE HAZARD IN SENSITIVE CLAY DEPOSITS

2020 ◽  
Author(s):  
Didier Perret ◽  
◽  
Remi Mompin ◽  
Pascal Locat ◽  
Denis Demers
Keyword(s):  
Landslide Hazard ◽  
Clay Deposits ◽  
Sensitive Clay

scholarly journals The influence of clay content on submarine slope failure: insights from laboratory experiments and numerical models

2020 ◽  
Vol 500 (1) ◽  
pp. 301-309 ◽  
Author(s):  
M. M. W. Silver ◽  
B. Dugan
Keyword(s):  
Pore Pressure ◽  
Slope Failure ◽  
Failure Modes ◽  
Initial Conditions ◽  
Numerical Models ◽  
Clay Content ◽  
Passive Margin ◽  
Slope Failures ◽  
Submarine Slope ◽  
Failure Evolution

AbstractSubmarine slope failures pose risks to coastlines because they can damage infrastructure and generate tsunamis. Passive margin slope failures represent the largest mass failures on Earth, yet we know little about their dynamics. While numerous studies characterize the lithology, structure, seismic attributes and geometry of failure deposits, we lack direct observations of failure evolution. Thus, we lack insight into the relationships between initial conditions, slope failure initiation and evolution, and final deposits. To investigate submarine slope failure dynamics in relation to initial conditions and to observe failure processes we performed physical experiments in a benchtop flume and produced numerical models. Submarine slope failures were induced under controlled pore pressure within sand–clay mixtures (0–5 wt% clay). Increased clay content corresponded to increased cohesion and pore pressure required for failure. Subsurface fractures and tensile cracks were only generated in experiments containing clay. Falling head tests showed a log-linear relation between hydraulic conductivity and clay content, which we used in our numerical models. Models of our experiments effectively simulate overpressure (pressure in excess of hydrostatic) and failure potential for (non)cohesive sediment mixtures. Overall our work shows the importance of clay in reducing permeability and increasing cohesion to create different failure modes due to overpressure.

scholarly journals Monitoring of recent mass movement activity in anthropogenic slopes of the Krušné Hory Mountains (Czech Republic)

2011 ◽  
Vol 11 (5) ◽  
pp. 1463-1473 ◽  
Author(s):  
J. Burda ◽  
L. Žižka ◽  
J. Dohnal
Keyword(s):  
Czech Republic ◽  
Slope Failure ◽  
Water Saturation ◽  
Mass Movement ◽  
Interdisciplinary Approach ◽  
Open Pit ◽  
Mass Movements ◽  
Slope Failures ◽  
The Czech Republic ◽  
Krušné Hory Mountains

Abstract. Recent mass movements currently comprise one of the main morphogenetic processes in the extensive anthropogenic relief of the foreground of the Krušné Hory Mountains in the Czech Republic. These mass movements result in several types of deep-seated slope failures, depending on the type of movement and the water saturation of the landslide material. This paper presents the results of a detailed geomorphic survey and orthophotograph analysis combined with geodetic monitoring data in an area affected by open-pit coal mining. An interdisciplinary approach has enabled an in-depth review of both the dynamics and development of recent slope failures. The article describes deep-seated landslide complex in this part of the foothills of the Krušné Hory Mountains. At the study site, mass movements occur in thick colluvial mantle and weathered Tertiary claystones. The main factors influencing their development include rainfall culminations, groundwater flowing from the valley of Šramnický Brook and former slope failures. All of the slope failures that have occurred here have originated at former slope failure sites.

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