CONTINUOUS MONITORING OF LANDSLIDES AREA CAUSED BY IWATE-MIYAGI NAIRIKU EARTHQUAKE IN 2008 USING ALOS IMAGES

摘要

The Iwate-Miyagi Nairiku earthquake struck inland area in northern Japan on June 14, 2008. This earthquake triggered landslides in mountainous area. The landslides changed land coverage from forest to bare soil. Aftermath of the disaster occurrence, many satellites observed target area to identify the damage. In this study, we report on long-term observation for damaged area using ALOS satellite after the earthquake occurrence. The landslide on north of the Aratozawa-dam lake is the largest one by this earthquake. The landslide area is identified by PALSAR single polarization intensity image. Sediments by the landslide were deposited into the dam lake and they caused rise of water level immediately after the earthquake. Temporal change of water level is observed by PALSAR single polarization intensity images. Normalized difference calculation from two of AVNIR-2 band 3 data is helpful to extract temporal change of landslide area. Pan-sharpen image of AVNIR-2 and PRISM is effective to extract small scale change on the damaged area. Satellite remote sensing data is records of reconstruction process and secondary damage for time span of several years.