Damage Extraction of the 2021 Off-Fukushima Earthquake based on PALSAR-2 Intensity Images

Remote sensing is useful to extract damages due to natural disasters. In this study, Synthetic Aperture Radar (SAR) images acquired from PALSAR-2 sensor onboard ALOS-2 satellite were used to observe damage situations due to the 13 February 2021 Off-Fukushima, Japan, earthquake. Landslides and rockfalls were reported at the Joban Expressway, a motor racing circuit, and seaside cliffs. Change detection using pre- and post-event PALSAR-2 intensity images was carried out and the results were compared with airborne optical images and field survey data. The landslide at the expressway and the motor circuit were recognized from the SAR intensity data, but rockfalls and other small-scale damages could not be identified due to the limitation of spatial resolution.