The Coseismic Insar Measurements of 2008 Yutian Earthquake and Its Inversion for the Fault Slip

Abstract

AbstractWe have obtained the coseismic deformation along line of sight of the 2008 Yutian earthquake, using PALSAR images and SAR interferometry technique. Based on these InSAR measurements and the constrained least square method, we studied the source parameters of this big normal event. Four schemes of inversion were constructed, with the emphasis on the effect to slip distribution inversion of the incidence angle and azimuth angle. Our inversion results show that the incidence angle has certain effect on the slip distribution, which means that a substitution of location‐dependent incidence angle with constant mean incidence angle will lose some useful slip distribution on fault plane. Our inversion also shows that the azimuth angle, however, has almost no obvious effect and it is an optimal choice to use the mean azimuth angle. Our most robust slip distribution can be obtained with the two parameters being location‐dependent. In our favored inversion scheme using location‐dependent angles for both, the maximum slip reaches 3.2 m. Slip is mainly confined to 0~14 km depth and no evidence of shallow slip deficit. The inverted seismic moment M0 is 3.3×1019 N·m, equivalent to an event of magnitude Mw7.0.