Real-time monitoring of Deep-seated gravitational slope deformation by TCP-InSAR technology and GPS time series analysis in the Taiwan mountain area

Abstract:

The Deep-seated gravitational slope deformation (DSGSD) on mountains area is widespread and overexploitation has increased the frequency of natural disasters such as landslides, rockslides, and debris flows. In Taiwan, the observation and the analysis of the deep-seated landslides suggest that these are mainly controlled by tectonic structures, which play a dominant role in the deformation of massif slopes. In the past few years, our research team has identified over 1500 DSGSD sites by using airborne LiDAR derived Digital Elevation Model (DEM). In this study, we used the multi-disciplinary approach including tectonic geomorphology, remote sensing, and geodesy to monitor their activity and susceptibility in mountainous area. Using available L-band SAR data of ALOS/PLASAR satellite, which could penetrate dense vegetation and used to estimate more ground deformation information to evaluate the activity and susceptibility of deep-seated gravitational deformation (DSGSD) which has potential transform to catastrophic landslide. On the other hand, surface displacements ranging from a few millimeters to several centimeters can be easily measured by continuous GPS (Global Positioning System). After the Typhoon Morakot, some GPS sites show reactivation landslide terrains associated with the Miocene to Eocene slates, corresponding to the area of highest altitudes. A continuous GPS site, TENC, located along the southern cross-island highway, shows a huge displacement of about 240 mm.