COUPLING ANALYSIS OF CONTROL FACTORS BETWEEN EARTHQUAKE-INDUCED LANDSLIDES AND SUBSEQUENT RAINFALL-INDUCED LANDSLIDES IN EPICENTER AREA OF WENCHUAN EARTHQUAKE

This paper selects typical study area in epicenter area of the Beichuan as the site for the landslides interpretations induced after the Wenchuan Earthquake on May 12, 2008 and the strong rainfall on September 24, 2009.It bases on high-resolution aerial photographs and remote sensing SPOT 5 imagery. The results are as follows.the number of the earthquake-induced landslides is 1999.the number of the rainfall-induced landslides is 828.the rainfall enlarged the 150 earthquake-induced landslides. The earthquake and the rainfall are powerful causes for the occurrence of landslides.the rainfall-induced landslide area is 25% larger than the earthquake-induced landslide area. So, the landslide number in the study areais increased by 41.4%.The strong rainfall not only induced new landslides but also made the original earthquake landslides raise, and to expand the area so that the landslide area increased by68.7%.Meanwhile, on the basis of remote sensing data interpretation, the paper further analyse the induced landslides, carries out the trends, hazard and risk evaluation, which provides a scientific prediction basis. The findings in this paper can be useful to the Wenchuan Earthquake restoration and reconstruction in disaster mitigation and preparedness and provide the decision-makers to carry out earthquake-induced landslides and rainfall-induced landslides scale contrast and control factor coupling analysis and the earthquake and rainfall coupling disasters chain mode.