Earth Planets Space, Vol. 58 (No. 12), pp. 1567-1572, 2006LETTER
Satoshi Miura, Takeshi Iinuma, Satsoshi Yui, Naoki Uchida, Toshiya Sato, Kenji Tachibana, and Akira Hasegawa
Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
(Received February 6, 2006; Revised December 5, 2006; Accepted December 6, 2006; Online published February 2, 2007)
A large earthquake with M7.2 occurred on August 16, 2005 along the plate boundary off Miyagi Prefecture. Co- and post-seismic deformations associated with this event were investigated to reveal the causal interplate slips using continuous GPS data and geodetic inversion. The coseismic slip distribution shows good agreement with that estimated by seismic waveform inversions. The major slip area is limited to the southeastern part of the rupture area of the previous 1978 event. The post-seismic slip extended to the southwest of the co-seismic slip area. These distinctive features of both the co- and post-seismic slips might be caused by the existence of the locked plate interface, where seismogenic stress has not released yet, in the northern part of the 1978 rupture area.
Key words: GPS, asperity, subduction zone, interplate earthquake, coseismic slip, after slip.