[H-TT17] Geographic Information System and Cartography

[HTT17-P03] Estimation of movement of Koshio Landslide by using multi-temporal point cloud data

Naoki Saito⁴, *Hiromu Daimaru¹, Ryuichi Sekoguchi⁵, Hideo Suzuki⁵, Kenichiro Toda², Wataru Murakami³ (1.Faculty of Bioresources and Environment Ishikawa Prefectural University, 2.Geoforest Corporation, 3.Forestry and Forest Products Research Institute, 4.Faculty of Bioresources and Environment Ishikawa Prefectural University (student), 5.Aero Asahi Corporation)

Keywords:Koshio Landslide, point cloud analysis, drone laser scanning, structure from motion

The Koshio landslide in Oshika Village, Nagano Prefecture is located near the Median Tectonic Line. This landslide is extremely active, with annual movement exceeding 50 cm in some years. We authors took aerial photographs of a larch forest on the upper slope of this landslide in November 2023 using a UAV, and conducted SfM analysis to obtain a point cloud. We compared this 2023 point cloud data with point cloud data measured by laser survey using a UAV in November 2018. The results revealed that most of the trees have moved westward at a rate of >4 cm/year in the last 5 years. This estimation was very harmonious with that estimated from GNSS observations by the Forestry Agency and interferometric SAR data by the GSI. In addition, some of the larch trees showed increasing upward slopes in the last five years.