Engineering Commons^™

A First-Order Second-Moment Framework For Probabilistic Estimation Of Vulnerability To Landslides, Marco Uzielli, S. Duzgun, B. V. Vangelsten

Geohazards

The object of the present paper, which synthesises a broader research effort by ICG (2006a), is the development of a probabilistic framework for the quantitative estimation of the vulnerability of the built environment to landslides. The method draws inspiration from an existing 3-dimensional qualitative framework proposed earlier by ICG (2005). As vulnerability is directly included in quantitative risk analysis (QRA), it would be beneficial to convert the conceptual framework to a quantitative perspective. It should be recognised that, in real investigations, the input parameters and the models used in vulnerability assessment are necessarily vague and imprecise, and are subjective to …

Instability In Soft Sensitive Clays, V. Thakur, G. Grimstad, S. Nordal

Geohazards

Soft sensitive clays like quick clays are well known in Scandinavia and in some regions in Canada. The salt pore water of these marine clays has been leached out since last glaciations and left a brittle mineral structure. Slides in quick clays can be extremely disastrous, as in Verdal, Norway in 1893 or Rissa in 1978. The slides may be initiated by local overloading, river erosion or similar and can escalate in size in a retrogressive manner in which large volumes of clay finally may liquefy. Norwegian quick clay has a very low permeability and hence pore water pressure becomes …

An Introduced Methodology For Estimating Landslide Hazard For Seismic Andrainfall Induced Landslides In A Geographical Information System Environment , M. D. Ferentinou, M. Sakellariou, V. Matziaris, S. Charalambous

Geohazards

The demand for estimating landslide hazard has evolved during the last decade. Landslides are characterised among the most severe natural hazards, which can cause casualties, fatalities, harm or detriment in natural and man-made environment.

In the first part of this paper the results of the research conducted on slope deformation due to seismic loading are presented. According to field observations deformation and displacement of natural and man-made slopes in strong earthquakes are common phenomena, even though they are associated to moderate magnitude seismic events. These permanent displacements are due to seismic loading, and are produced because the material, through which …

The Importance Of Laboratory Experiments In Landslide Investigation, Barbara Schneider-Muntau, D. Renk, T. Marcher, Wolfgang Fellin

Geohazards

This study focuses on a better understanding of mass movements and on the influences of different boundary conditions on velocities of creeping slopes. A well monitored example of a slowly creeping landslide is the mass movement Hochmais - Atemkopf, situated in the Kaunertal, Tyrol, Austria (Fig. 1). The long term monitoring program for more than 40 years of this landslide gives a good impression of its time dependent behaviour. A large amount of additional data, as geological mapping, boreholes, geophysical investigation and so on provides a funded base for the model’s geometry. The most influencing factor for finite element …

Landslide Hazard In El Salvador, Carlos Eduardo Rodriguez, A. T. Torres, E. A. León

Geohazards

The destructive seismic events of January 13 (ML: 7.6) and February 13 (ML: 6.1) 2001 in El Salvador, with origin in the subduction area and the volcanic chain, respectively, provide an ideal scenario to analyse the factors that define the landslide hazard in this country. In this paper we analysed the events in terms of strong-motion and precedent climatic condition and their relation with the landslides induced; establishing a great opportunity to compare some hazard assessment methods as those proposed by Mora and Vahrson (1994) and Rodríguez (2001) which define the hazard in terms of the interaction between triggering agents …

Landslide Hazard Assessment At “Sakhalin-2” Main Pipeline Project, S. I. Matsiy, A. P. Sheglov, D. V. Pleshakov

Geohazards

In the given article, 2 various approaches to a landslide hazard assessment are considered. Landslide hazard means probability of a slope failure. The calculations have been carried out using a landslide hazardous section of Sakhalin-2 main pipeline route as an example.

Predicting Rainfall-Induced Movements Of Slides In Stiff Clays, Michele Calvello, Leonardo Cascini

Geohazards

A physically-based numerical method is presented for displacements hazard analyses, at large-scale, in the case of landslides characterized by movements along pre-existing slip surfaces induced by rainfall-triggered pore pressure fluctuations. The method comprises a transient seepage finite element analysis and a kinematic model. With reference to the latter, the rates of displacement are assumed to be of the viscous type and are related to the factors of safety along the slip surface computed performing time-dependent limit equilibrium analyses. Monitoring data from an active slide in Central Italy are then used both for calibrating the models, by means of an inverse …

Earthquake-Induced Landslides In Colombia, Carlos Eduardo Rodriguez

Geohazards

Landslides due to earthquakes in Colombia have been historically reported since 1530 when ground cracking, soil movements and liquefaction events were induced by an earthquake which magnitude has not been defined. Since then more than thirty earthquakes have been identified to have produced landslides in the country, in some cases consequences related to landslides have been more significant than those due to direct effects of the earthquake itself.

The author has compiled a database of landslides induced by earthquakes in Colombia from which relationships between earthquake magnitude and landslide characteristics have been explored. It has been found that residual and …

Influence Of Degrading Permafrost On Landsliding Processes: Little Salmon Lake, Yukon Territory, Canada, R. Lyle, D. Jean Hutchinson

Geohazards

A landslide inventory was carried out for the Little Salmon Lake area, Yukon Territory, Canada, in response to observations of several new landslides in the area, suspected to be the result of degrading permafrost. The largest of these landslides, the Magundy River bi-modal flow-slide, has progressed over the last decade until it now involves over 1x106 m3 of material. The inventory is based on terrain mapping and field work, and includes multiple landslide types. The field work provided the opportunity to examine the slides, ground truth the map, and to examine the progression of the landslide, as well as the …

Hydrodynamics And Rheology: Key Factors In Mechanisms Of Large Landslides, L. Bonzanigo, P. Oppizzi, M. Tornaghi, A. Uggeri

Geohazards

When checking the behaviour of large landslides, deterministic stability analysis has little sense. Stability coefficients can only be seen as the relationship between acting and reacting forces. In fact, large landslides simply move in any case, more or less quickly. When stable, the displacements are actually so small that they aren't detectable. Thus the so called security factor could always be set to unity, and the computations performed as back analysis. The transition from a very slow viscous displacement to a catastrophic failure is better described in a change of rheological behaviour than in an overtaking of a stability coefficient. …

Risk Analyses And Risk Management - Slope Instabilities In Alpine Environments, S. Eder, G. Poscher, C. Prager

Geohazards

Two prominent deep-seated gravitational slope deformations in the Eastern Alps (Tyrol, Austria) have been activated in the last seven years and pose serious threats to the densely populated valleys. Based on multidisciplinary field investigations, different hazard scenarios of slope failures have been evaluated for risk management processes. These event scenarios, which are characterised by strongly varying volumes of the failing slide masses as well as by different probabilities of occurrence, and varying disintegration factors control different accumulation and damage scenarios. Finally, these evaluations and risk analyses aimed to define “design events”, i.e. which scenarios are relevant for the dimensioning of …

Quantitative Risk Assessment As Applied To Natural Terrain Landslide Hazard Management In A Mid-Levels Catchment, Hong Kong, Ian Muir, K. K. S. Ho, H. W. Sun, T. H. H. Hui, Y. C. Koo

Geohazards

This paper presents a case study of the application of quantitative risk assessment techniques to a site-specific natural terrain hazard study in Hong Kong. The development of the landslide hazard and susceptibility models is described and salient details of the consequence model are given, including the assessment of debris flowpaths and runout using state-of-the-art Geographic Information System (GIS) tools and debris runout computer models. A synthesis of the risk quantification process and schematic design of risk mitigation works is presented.

Studies Of The Gaviota Slide Offshore Southern California, Mark Zumberge, Jeff Babcock, Hugh H. Banon, John Blum, C. D. Chadwell, Jeff Dingler, Neal Driscoll, Gerald D'Spain, Philippe Jeanjean, Graham Kent, Graham Openshaw, John Orcutt

Geohazards

We are engaged in a study of a seafloor landslide off the coast of Santa Barbara, California. A large scar there remains from the Goleta slide, a well studied feature (1.51 km3 of failed material) that likely failed several thousand years ago. A smaller neighboring feature, the Gaviota slide (0.02 km3 of failed material), was probably triggered during the 1812 Santa Barbara earthquake. Our investigations started in 2004 with a chirp sonar survey. The survey revealed a relationship between a “crack” in the sediment propagating from the Gaviota slide’s headwall and a thrust fault clearly seen in the subsurface layers. …

The 1999 Colorado Springs, Colorado Landslides – Federal, State And Local Government Response; Public Involvement; And Future Long-Term Risks And Challenges, Mark W. Squire

Geohazards

In the spring of 1999, heavy rain precipitated landslides in over 12 developed areas in Colorado Springs. The landslide damage and destruction exceeded $80 million dollars. A combined federal, state and local response included active participation by property owners in an open and transparent public process. The resulting federally funded mitigation project was a success, but this can only be considered an interim objective for an inherent serious local problem. Colorado Springs is normally an arid environment but high moisture years, like 1999, can result in activation of new landslides and reactivation of existing landslides. Residential neighborhoods continue to expand …