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 − 3.5 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.

本研究以2019年4月18日发生的花莲地震为研究对象，以Sentinel-1A/B SAR影像为数据源，通过DInSAR和MAI技术提取变形场，基于干涉图、地质结构、余震分布、垂直 PGA 监测结果。研究结果表明，震源区附近地表沉降最大位移在LOS方向可达3.6 cm，震源区附近最大方位角位移可达-3.5 cm，均小于4.0 cm。也就是说，本次地震引起的双向位移在研究区并不显着。而前人的研究结果间接暗示了震源区附近变形场的提取结果是合理的。然后，根据前人在地质构造、区域构造、逆向地震破裂和 PGA 等方面的研究成果，通过对研究区地表变形场、垂向 PGA 结果和地表覆盖类型的分析，可以看出，由于地形对地震波折射和反射的影响，地形对垂直PGA的影响超过了震中距。