[H-DS08] 地すべりおよび関連現象

[HDS08-P07] Slope disaster detection and triggering factor analysis via integrated use of time-series optical and SAR satellite data in Kyushu Island, Japan

*水落 裕樹¹、松岡 萌¹、山本 聡¹、宮崎 一博¹、阿部 朋弥¹、星住 英夫¹、川畑 大作¹、岩男 弘毅¹、宮地 良典¹ (1.産業技術総合研究所)

キーワード：斜面災害モニタリング、長期光学衛星データ、InSAR解析、トレンド分析

Recently, satellite remote sensing is an essential tool for slope disaster observation. Taking advantage of large data archive of optical and microwave (i.e., synthetic aperture radar: SAR) satellite images, we provided time-series analysis of sloping area in Kyushu Island, which is one of the high-risk areas of slope disaster in Japan. Specifically, anomaly detection algorithm using the open-free optical data (i.e., Landsat) was conducted to automatically extract disturbed forest area, including slope disaster such as debris flow and slope failure. In addition, time-series interferometric SAR (InSAR) using Phased-Array L-band Synthetic Aperture Radar-2 (PALSAR-2) visualized centimeter-scale displacement of the sloping area for the last decade. The displacement polygons, which are assumable to be susceptible area of future landslide, were delineated based on GIS analysis. Field survey in several accessible test sites showed that 50~60% of the extracted area truly indicated displacement signatures on the infrastructure. Detailed comparison of the spatial distribution of the susceptible polygons with geomorphological features in Sasebo region revealed that the importance of the geological background such as rock type, accumulation history of the past landslide debris, and inclination and direction of the bedding plane.