TY - JOUR
T1 - Slip distribution of the 2011 Tohoku earthquake derived from joint inversion of GPS, InSAR and seafloor GPS/acoustic measurements
AU - Wang, Chisheng
AU - Ding, Xiaoli
AU - Shan, Xinjian
AU - Zhang, Lei
AU - Jiang, Mi
PY - 2012/9/5
Y1 - 2012/9/5
N2 - We invert the fault slips of 2011 Mw 9.0 Tohoku earthquake with constraints from GPS, InSAR and seafloor GPS/acoustic measurements. The seismogenic fault geometry is constructed according to slab contours of Japan Trench. Steepest Descent method and Laplacian smoothing are used to solve slip distribution and regularize the solution. We firstly take GPS displacement in two postseismic periods, the first 8h right after mainshock from 5:55 to 14:00 UTC and the 13days from 12 March 2011 to 25 March 2011, to solve for the postseismic slips. The solved postseismic slips are adopted to remove postseismic signal in InSAR and seafloor observation. In order to estimate the effect of postseismic correction and contribution from different geodetic datasets, we invert several coseismic slips with constraints from GPS (Model 1), corrected InSAR (Model 2), combination of GPS and corrected seafloor measurements (Model 3), combination of GPS and corrected InSAR and seafloor measurements (Model 4), and combination of GPS and initial InSAR and seafloor measurements (Model 5). From the comparison of these slip models, we find combined datasets could give more slip details, which is closer to a joint inversion result constrained from both seismic and geodetic datasets (Koketsu et al., 2011). RMSE of seafloor measurements has dropped about 4cm after applying postseismic correction. We consider the Model 4, which combines three datasets and takes postseismic correction, to be the preferred solution among all the estimated models. It suggests a maximum slip of 49.87m, located at a depth of 5km around the epicenter, and has a geodetic moment of 3.14×1022Nm (Mw 8.96) by assuming a shear modulus of 4×1010Pa.
AB - We invert the fault slips of 2011 Mw 9.0 Tohoku earthquake with constraints from GPS, InSAR and seafloor GPS/acoustic measurements. The seismogenic fault geometry is constructed according to slab contours of Japan Trench. Steepest Descent method and Laplacian smoothing are used to solve slip distribution and regularize the solution. We firstly take GPS displacement in two postseismic periods, the first 8h right after mainshock from 5:55 to 14:00 UTC and the 13days from 12 March 2011 to 25 March 2011, to solve for the postseismic slips. The solved postseismic slips are adopted to remove postseismic signal in InSAR and seafloor observation. In order to estimate the effect of postseismic correction and contribution from different geodetic datasets, we invert several coseismic slips with constraints from GPS (Model 1), corrected InSAR (Model 2), combination of GPS and corrected seafloor measurements (Model 3), combination of GPS and corrected InSAR and seafloor measurements (Model 4), and combination of GPS and initial InSAR and seafloor measurements (Model 5). From the comparison of these slip models, we find combined datasets could give more slip details, which is closer to a joint inversion result constrained from both seismic and geodetic datasets (Koketsu et al., 2011). RMSE of seafloor measurements has dropped about 4cm after applying postseismic correction. We consider the Model 4, which combines three datasets and takes postseismic correction, to be the preferred solution among all the estimated models. It suggests a maximum slip of 49.87m, located at a depth of 5km around the epicenter, and has a geodetic moment of 3.14×1022Nm (Mw 8.96) by assuming a shear modulus of 4×1010Pa.
KW - Fault slip
KW - Joint inversion
KW - Tohoku earthquake
UR - http://www.scopus.com/inward/record.url?scp=84865098889&partnerID=8YFLogxK
U2 - 10.1016/j.jseaes.2012.06.019
DO - 10.1016/j.jseaes.2012.06.019
M3 - Journal article
SN - 1367-9120
VL - 57
SP - 128
EP - 136
JO - Journal of Asian Earth Sciences
JF - Journal of Asian Earth Sciences
ER -