In the III-D block (800m long) of the Gampei landslide, Joetsu City, Niigata Prefecture, we investigated the flow characteristics and changes of the surface conditions on the landslide, using UAV aerial photography, optical and SAR satellite data, and GNSS survey. The III-D block has moved continuously since 2010, and the sliding velocity in winter was higher than that in summer. In addition, the changes in surface conditions such as tree collapse and the development of gully and valley were classified with stages of dissection process.
In this study, we compared the amount of movement obtained by DInSAR analysis and LiDAR for the Shirakouchizawa landslide located near Mt. Asahi, the northern Japanese Alps, to investigate the characteristics of the landslide displacement detected by DInSAR analysis. The actual amount of movement calculated from the LiDAR data was converted to the amount of movement in the line-of-sight (LOS) direction. We used measurement sensitivity as an index that indicates how much the LOS of the DInSAR analysis differs from the actual amount of movement due to LiDAR LOS depending on the slope direction and angle. As a result of comparing the two methods, the LOS of the DInSAR analysis was close to the actual displacement at the location with high measurement sensitivity, and the value of that was smaller than the actual displacement at the location with low measurement sensitivity.