Extraction of coseismic displacement in the November 22, 2014 Nagano, Japan earthquake from ALOS-2 images

Abstract

An Mw6.2 earthquake hit northern Nagano prefecture, Japan on November 22, 2014, with 46 people injured and a lot of damage to houses. Due to the fault movement, about 1-m displacement was observed by field surveys after the earthquake. Interferomatic SAR (InSAR) analysis has been confirmed as an effective tool to detect displacements in the centimeter level. In this study, the pre- and post-event ALOS-2 PALSAR-2 data were used to grasp the displacements around the Kamishiro Fault by the differential InSAR analysis. The slant range movements were obtained according to the phase differences. Then a fault model was built by introducing the parameters published by the Global Centroid-Moment-Tensor Catalog. A three-dimensional displacement was simulated using the fault model and it was compared with the observation result by a GPS ground station and at a strong-motion station.