Characteristics of the Torrential Rainfall-Induced Shallow Landslides by Typhoon Bilis, in July 2006, Using Remote Sensing and GIS

Abstract

During July 14–16, 2006 Typhoon Bilis swept over the southern China. The typhoon brought torrential downpour, resulting in many shallow landslides in the region. This study describes the characteristics of the landslides in an area around the Dongjiang Reservoir, Hunan Province, which was seriously affected by the event. We sketch the landslide occurrences and extreme rainfall event in the study area based on the high-resolution QuickBird images, medium-scale China-Brazil Earth Resources Satellite (CBERS) images, rain gauge data, a digital elevation model, and field surveys. All the satellite images, rain gauge points, geological maps, and field notes were processed and constructed into a spatial database in a GIS platform. The landslide occurrences in the study area before the event was low, and significantly increased during and after Typhoon Bilis of 2006. The short duration, high-intensity rainfall was the major triggering factor. In addition, topographical factors such as slope and aspect also contributed to landslide occurrence. The combined influence of rainfall and the topographic factors. The paper attempts to provide a better understanding of the rainfall and causative factors of landslides in the wake of typhoon Bilis.