The multitemporal change analysis of deep-seated landslide - Hsiaolin Slide

Due to the active collision between Eurasian and Philippine Sea tectonic plates, the rocks of Taiwan are highly fractured and vulnerable to slope failures. In addition, Taiwan lies in the track of severe tropical cyclones known in East Asia as typhoons. Deep-seated landslides caused by heavy rainfall are usually catastrophic. One of the most catastrophic disaster is Hsiaolin Slide triggered by typhoon Morakot occurred on 9th August 2009 at Shiaolin Village in Kiaosiung City of Southern Taiwan. It was reported that 450 people died in this landslide, of which the volume was about 26 million cubic meters. Airborne LiDAR was conducted to acquire digital elevation models for landform change study after the event on 18 and 23 June 2010 and on 16 and 27 October 2010. The same area was surveyed with airborne LiDAR in 2006. Thus, three times of airborne LiDAR surveys were carried out. With the change from 2006 to June 2010, accurate landslide volume can be estimated. With the change from June to October, local slope of instability was readily identifiable on the difference image. It is concluded that multi-temporal airborne LiDAR can be an effective approach for quantifying the time-series change of deep-seated landslides in the physiographic settings of Taiwan.