Predicting storm-triggered landslides

Abstract

An overview of storm-triggered landslides is presented. Then a recently developed and extensively verified landslide modeling system is used to illustrate the importance of two important but presently overlooked mechanisms involved in landslides. The model's adaptive design makes the incorporation of new physical mechanisms convenient. For example, by implementing a land surface scheme that simulates macropore features of fractured sliding material in the draining of surface ponding, it explains why precipitation intensity is critical in triggering catastrophic landslides. Based on this model, the authors made projections of landslide occurrence in the upcoming 10 years over a region of Southern California, using atmospheric parameters provided by a high resolution climate model under a viable emission future scenario. Current global coupled ocean–atmosphere climate model (CGCM) simulations of precipitation, properly interpreted, provide valuable information to guide studies of storm-triggered landslides. For the area of interest, the authors examine changes in recurrence frequency and spatial distribution of storm-triggered landslides. For some locations, the occurrences of severe landslides (i.e., those with a sliding mass greater than 104 m3) are expected to increase by ~5% by the end of the twenty-first century.The authors also provide a perspective on the ecosystem consequences of an increase in storm-triggered mudslides. For single plants, the morphological features required for defense against extreme events and those required to maximize growth and reproduction are at odds. Natural selection has resulted in existing plants allocating just enough resources to cope with natural hazards under a naturally varying climate. Consequently, many plant species are not prepared for the expected large changes in extremes caused by anthropogenic climate changes in the present and future centuries.