Earth Planets Space, Vol. 56 (No. 2), pp. 95-101, 2004
Satoshi Miura, Yoko Suwa, 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 October 14, 2003; Revised January 29, 2004; Accepted February 9, 2004)
On July 26, 2003, a disastrous earthquake with M6.4 struck the northern part of Miyagi prefecture, northern Honshu, Japan. GPS measurements and leveling surveys conducted by the Geographical Survey Institute (GSI) revealed clear evidence of coseismic deformation. We analyzed those data using a geodetic inversion to estimate the slip distribution on a curved fault plane, which is suggested by precise hypocenter determination performed by Tohoku University. The maximum slip area is located at the northern and shallower part of the fault plane, which is consistent with the slip distribution obtained by seismic waveform inversion. The spatial pattern of slip direction also shows good agreement with that of the focal mechanism.
Key words: GPS, leveling survey, 2003 northern Miyagi earthquake (M6.4), geodetic inversion, slip distribution.