Large earthquake-triggered landslides and mountain belt erosion: The Tsaoling case, Taiwan

The 1999 Chi-Chi earthquake triggered the catastrophic Tsaoling landslide in central Taiwan. We mapped the landslide area and estimated the landslide volume, using high-resolution digital elevation model from airborne LiDAR (Light Detection and Ranging), satellite images, aerial photographs and topographic maps. The comparison between cut and fill volumes, about 0.126 and 0.150 km(3), respectively, suggests a volume increase of 19% due to decompaction during landsliding. In April 2002, the cut and fill volumes were about 0.137 and 0.116 km(3), respectively. These estimates suggest that 2.5 years after the event, the volume of landslide debris removed by river erosion was nearly 0.045 km(3). Such a large value highlights the importance of landslide processes for erosion and long-term denudation in the Taiwan mountain belt.