The Extraction and Analysis of Deformation Features of Hualien Earthquake Based on Sentinel-1A/B SAR Data

Abstract

Focusing on Hualien earthquake which happened on April 18th in 2019, this research took Sentinel-1A/B SAR images as data source, extracted deformation field through DInSAR and MAI technology, analyzed deformation features based on interferogram, geological structure, distribution of aftershocks and the vertical PGA monitoring results. Our results showed that the maximum displacement of land surface subsidence near the seismic focus areas in LOS direction reached up to 3.6 cm, and the maximum displacement near the seismic focus areas in azimuth direction reached up to\u2009−\u20093.5 cm, both less than 4.0 cm. That was to say, the displacement in both direction caused by this earthquake was not significant in study area. And the previous research results indirectly implied that the extraction results of deformation field were reasonable near the seismic focus area. Then, based on the previous research results on geological structure, regional tectonics, reverse-type earthquake rupture and PGA, through the analysis on surface deformation field, vertical PGA results and surface cover types in the study area, we could indicate that, due to the effect of terrain on refraction and reflection of seismic wave, the impact of terrain on vertical PGA exceeded that of the epicentral distance.