Mapping surface deformation related to the 2008 Wenchuan earthquake with ALOS InSAR and GPS observations

The Ms8.0 Wenchuan earthquake occurred on May 12, 2008 in Wenchuan County, Sichuan Province, China. The devastating event caused a significant surface rupture and deformation in a large geographical area. This study intends to investigate the co-seismic surface deformations due to the main shock by integrating observations from interferometric synthetic aperture radar (InSAR) and global positioning system (GPS). The InSAR measurements in an area of more than 83,000 km are extracted from 46 SAR images that were acquired along 6 adjacent ascending orbits by the ALOS L-band PALSAR sensor. The three-dimensional displacements measured at 16 GPS stations are used to validate and calibrate the InSAR measurements by a least squares fitting, and thus removing the unwanted components due to atmospheric delay, orbital uncertainty and topographic bias. The preliminary results show that such an integrated method is useful for mapping the co-seismic surface deformation.