Mapping earthquake-induced damage of the Wenchuan earthquakeusing SAR data

摘要

Due to the adverse weather condition such as raining after the Wenchuan earthquake, the applicability of optical imagery in decision making for mitigating earthquake disasters had been highly restricted. As a synthetic aperture radar (SAR) sensor possesses all-weather imaging capability, SAR imagery emerges as a very important data source for earthquake rescue operation at the earlier stage. This paper utilizes 4 pairs of ENVISAT ASAR images (3 pre-earthquake, I post-earthquake) to perform ratio coherence change detection by comparing pre-seismic between post-seismic images over Dujiangyan City and its neighboring areas. The testing results indicate that the interferometric coherence map is sensitive to physical surface changes and show that there were significant changes within the urban area and the main shock had caused substantial damage. This study demonstrates that it is feasible to use SAR images to conduct damage assessment. With the polarization radar technology becoming more sophisticated, radar satellites in decision making for disaster rescue will play more and more important role.