COSEISMIC DISPLACEMENT AND FAULT SLIP OF THE MW6.1 NAPA EARTHQUAKE IN AMERICA REVEALED BY SENTINEL-1A INSAR DATA |
| |
| Authors: | ZUO Rong-hu QU Chun-yan ZHANG Guo-hong SHAN Xin-jian SONG Xiao-gang WEN Shao-yan XU Xiao-bo |
| |
| Institution: | State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China |
| |
| Abstract: | We achieved the coseismic displacements of the Napa MW6.1 earthquake located in California US occurring on 24 August 2014 by using InSAR data from the newly launched ESA's Sentinel-1A satellite. The 30m×30m ASTER GDEM was used to remove the terrain effect, and phase unwrapping method of branch-cut algorithm was adopted. In order to obtain a better coseismic displacement field, we also tested 90m×90m SRTM data to remove the terrain effect and Minimum Cost Flow algorithm to unwrap the phase. Results showed that the earthquake caused a significant ground displacement with maximum uplift and subsidence of 0.1m and -0.09m in the satellite light of sight(LOS). Based on the Sentinel-1A dataset and sensitivity based iterative fitting(SBIF) method of restrictive least-squares algorithm, we obtained coseismic fault slip distribution and part of the earthquake source parameters. Inversion results show that the strike angle is 341.3°, the dip angle is 80°, rupture is given right-lateral fault, average rake angle is -176.38°, and the maximum slip is ~0.8m at a depth of 4.43km. The accumulative seismic moment is up to 1.6×1018N·m, equivalent to a magnitude of MW6.14. |
| |
| Keywords: | Sentinel-1A Napa earthquake D-InSAR coseismic displacement inversion |
|
|
