Landslide hazard analysis for the 2008 Wenchuan Earthquake using landslide inventory and GIS

摘要

The 12 May 2008 Wenchuan earthquake (Mw=8.0) triggered widespread and large scale landslides over an area of about 80,000 k.m2. A study was undertaken to determine the primary factors associated with seismic landslide occurrence. The approach used to assess landslide hazard in the central part of the Wenchuan earthquake area affected is described. A numerical rating system was applied to six factors that may have contributed to the occurrence of the Wenchuan earthquake landslides. Lithology, slope gradient, elevation, fault proximity, stream proximity, and antecedent rainfall are recognized as factors that may have had an important influence on triggering landslides. The assessment of the influence of each of these factors is presented through use of a series of maps showing areas of low, moderate, and high landslide haz- ard. Areas identified as having 'high landslide hazard' were located along the earthquake-source fault and along both banks of the Jian river. The results of this study will assist future decision makers in the selection of safe sites for temporary housing of refugees and in the site-planning process for future reconstruction. The maps can also be used for landslide riskmanagement in the study area.