The quantification of risk has gained importance in many disciplines, including landslide studies. The literature on landslide risk assessment illustrates the developments which have taken place in the last decade and that quantitative risk assessment is feasible for geotechnical engineering on a site investigation scale and the evaluation of linear features (e.g., pipelines, roads). However, the generation of quantitative risk zonation maps for regulatory and development planning by local authorities still seems a step too far, especially at medium scales (1:10,000–1:50,000). This paper reviews the problem of attempting to quantify landslide risk over larger areas, discussing a number of difficulties related to the generation of landslide inventory maps including information on date, type and volume of the landslide, the determination of its spatial and temporal probability, the modelling of runout and the assessment of landslide vulnerability. An overview of recent developments in the different approaches to landslide hazard and risk zonation at medium scales is given. The paper concludes with a number of new advances and challenges for the future, such as the use of very detailed topographic data, the generation of event-based landslide inventory maps, the use of these maps in spatial-temporal probabilistic modelling and the use of land use and climatic change scenarios in deterministic modelling.

https://www.geo.uzh.ch/~chuggel/riskcourse/vanwesten_landsl_hazard_risk_zonation_bege06.pdf

Landslide hazard and risk zonation—why is it still so difficult?

Movements and failure of cuts and natural slopes constitute an important geotechnical problem that involves a variety of geomaterials in a variety of geological and climatic contexts, and which has a major socio-economic impact in many countries. The paper reviews the state of knowledge in this domain, examining the basic aspects of soil mechanics that are relevant to the context of slopes, the importance of water on slope behaviour, and then the different stages of slope movements: pre-failure, failure, post-failure and reactivation. Finally it is shown how the geotechnical characterisation of slope movements can be used, in particular for assessing risk associated with such movements. Emphasis is put on for the brittleness of soils and its practical implications for the progressive failure developing at the pre-failure stage and on the characteristics of post-failure movements. The influence of other factors such as creep, fatigue, destructuration, partial saturation and infiltration is also considered.

https://www.icevirtuallibrary.com/doi/pdf/10.1680/geot.2001.51.3.197

Natural slopes and cuts: movement and failure mechanisms

/pdf/landslide-hazard-and-risk-issues-concepts-and-approach-2ilwpua8u6.pdf

Landslide Hazard and Risk: Issues, Concepts and Approach

¶This paper compiles and analyzes the rockfall data in Hong Kong in the last fifty years. A simple rockfall hazard analysis is presented based on this rockfall inventory. A frequency-magnitude relation, which is analogous to the Gutenberg-Richter relation for earthquake occurrence, is proposed for rockfall, and direct correlation between rockfall frequency and the daily rainfall is observed. Data analysis shows that a threshold daily rainfall of about 150–200 mm is expected in order to trigger rockfall events in Hong Kong. Among the 368 rockfall events in the 13 year period from 1984 to 1996 in Hong Kong, 35% of the incidents lead to blockage of or damage to roads, 22% lead to damages or evacuation of squatter huts, 21% lead to blockage of pedestrian pavement and footpath, and 15% affect buildings, such as housing apartments and schools. Only 15% of these rockfalls fell onto open space and caused negligible effects on human activities. Most of these rockfall events occurred during heavy rain and when “landslide warning” should has been issued by the Hong Kong Observatory, thus only 6% of these events led to injury or casualty, car damages, and damages to public utilities. Rockfall hazard zonation maps in terms of the spatial distribution of previous rockfalls are proposed for both Kowloon Peninsula and Hong Kong Island.

Rockfall Hazard Analysis for Hong Kong Based on Rockfall Inventory

The last few decades have demonstrated an increased concern for the occurrence of natural disasters and their consequences for leaders and organizations around the world. The EMDAT International Disaster Database [1] statistics show that, in the last century, the mortality risk associated with major weather-related hazards has declined globally, but there has been a rapid increase in the exposure of economic assets to natural hazards.

/pdf/conceptual-frameworks-of-vulnerability-assessments-for-5bjb3dudoq.pdf

Conceptual Frameworks of Vulnerability Assessments for Natural Disasters Reduction

The quantification of risk is gaining importance in many fields, including geotechnical engineering. Landslide risk management systems are gradually maturing in various countries. Following a review of acceptable risks and the psychology of risk perception, a study of landslide risk perception in Australia and Hong Kong is detailed. The general views of those surveyed on landsliding, issues of land development regulation and remedial costs, a comparison of landsliding to other hazards, cognitive structures, the perception of a quantified annual loss of life frequency, a ranking of various landslide situations to each other, and acceptable probabilities of landsliding for loss of life and property damage were obtained, analysed, and discussed.

R Fell

Papers

Landslides: risk perception and acceptance