Mapping of ground surface deformations and its associated damage using SAR interferometry: a case study of the 2020 Masbate earthquake

Abstract

The 2020 Masbate earthquake in the Philippines, with a moment magnitude 6.6, occurred on August 18, 2020. The earthquake dealt considerable damage to the surrounding areas. This study uses Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) to investigate earthquake-induced damages. Conventional repeat-pass InSAR is used to quantify the ground surface displacement along the radar line-of-sight (LOS). The InSAR technique shows ground surface displacements greater than 15 cm. This study also implements a two-step coherence difference analysis coupled with a statistical temporal coherence threshold to map and delineate the locations of damages associated with the earthquake. The InSAR-derived damage locations are consistent with the actual locations of damages, as reported from a field survey. This study confirms the effectiveness and accuracy of Sentinel-1 InSAR techniques for earthquake-induced damage mapping applications.