Key Factors Influencing the Mechanism of Rapid and Long Runout Landslides Triggered by the 2008 Wenchuan Earthquake, China
The 2008 Wenchuan earthquake triggered many rapid and long runout landslides, which directly caused great loss of properties and human lives and were responsible for a large percentage of total damages caused by the earthquake. It is very important for future landslide mitigation programme to understand the earthquake-induced mechanism of initiation and motion of rapid and long runout landslides, which can potentially be the deadliest of ground failures. In this paper, field investigations of some typical landslides caused by the Wenchuan earthquake are introduced first, and followed by data from ring shear tests used to simulate the initiation and motion of one landslide in particular, the Donghekou landslide. It was found that valley water and groundwater played key roles in the rapid motion and long runout process of this landslide during the great earthquake. It was also observed that hazardous effects from the slowing of movement and/or a short runout, due to various geologic and hydrologic conditions of other landslides caused by the Wenchuan earthquake, contrasts with those which caused more deaths and damages due to rapid, long runout movement. Implications from this analysis suggest that decision-makers for future hazard mitigation and land use planning should be advised to be aware of the geotechnical and hydrological properties of their local areas where possible.
KeywordsWenchuan earthquake Rapid and long runout landslides Initiation Motion Hydrogeological condition
The field investigation and sampling was partially supported by Chinese State Key fundamental Research Program project (2008 CB425802, representative: P. Cui). The authors deeply appreciated the discussions with Prof. XY Wu of Southwest Jiaotong University, China, Prof. K. Konagai of University of Tokyo, Prof. S. Tsuchiya of Shizuoka University, Japan in the field investigation. The ring shear tests were conducted when the first author worked in Disaster Prevention Research Institute of Kyoto University, Japan.
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