HR: 1340h
AN: S43A-1042    [Abstracts]
TI: Rupture process of the 2005 M7.2 Miyagi-Oki, NE Japan, earthquake inferred from coseismic slip and aftershock distributions, and its comparison with the 1978 M7.4 Miyagi-Oki earthquake
AU: * Okada, T
EM: okada@aob.geophys.tohoku.ac.jp
AF: Research Center for Prediction of Earthquake and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 9808578 Japan
AU: Yaginuma, T
EM: yagi@aob.geophys.tohoku.ac.jp
AF: Research Center for Prediction of Earthquake and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 9808578 Japan
AU: Umino, N
EM: umino@aob.geophys.tohoku.ac.jp
AF: Research Center for Prediction of Earthquake and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 9808578 Japan
AU: Kono, T
EM: kono@aob.geophys.tohoku.ac.jp
AF: Research Center for Prediction of Earthquake and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 9808578 Japan
AU: Matsuzawa, T
EM: matuzawa@aob.geophys.tohoku.ac.jp
AF: Research Center for Prediction of Earthquake and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 9808578 Japan
AU: Kita, S
EM: kita@aob.geophys.tohoku.ac.jp
AF: Research Center for Prediction of Earthquake and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 9808578 Japan
AU: Hasegawa, A
EM: hasegawa@aob.geophys.tohoku.ac.jp
AF: Research Center for Prediction of Earthquake and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 9808578 Japan
AB: A large (M7.2) interplate earthquake occurred on 16 August 2005 in the Miyagi-Oki region, NE Japan. In this area, large interplate earthquakes with magnitude of ~M7.5 occurred repeatedly at a recurrence interval of ~37 yrs. Base on this recurrence of large earthquakes, the Headquarters of Earthquake Research Promotion of the Japanese government released the information of high probability (~50 percents within 10 years from now) of the impending earthquake to the public. To compare the aftershock distribution of the 2005 Miyagi-Oki earthquake with that of the previous (1978) Miyagi-Oki earthquake (M7.4), we relocated hypocenters of the aftershocks using double-difference method (Waldhauser and Ellsworth, 2000). Spatial extent of the aftershock area of the 2005 event is 80km and 40km in dip and strike directions, respectively. High aftershock activity was observed in the central part of the aftershock area, which is located to north-west of the mainshock hypocenter. The aftershock area of the 2005 event is overlapped with the southern/south-eastern part of that of the 1978 event. Locations of the aftershock clusters of the 2005 event correspond with those of the 1978 event and those of the background seismicity. We estimated coseismic slip distribution of the 2005 event by seismic waveform inversion by a method of Yagi et al. (2004). Obtained coseismic slipped area of the 2005 event extended mainly to the dip (northwest) direction, which is almost correspond with the area with high aftershock activity, and also partly overlapped with that of the 1978 event (Yamanaka & Kikuchi, 2004). These observations suggest that the spatial seismicity pattern on the plate boundary in subduction zone persists in time and the 2005 event have ruptured one of the asperities which caused the 1978 M7.4 event.
UR: http://www.aob.geophys.tohoku.ac.jp/
DE: 7209 Earthquake dynamics (1242)
DE: 7215 Earthquake source observations (1240)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7240 Subduction zones (1207, 1219, 1240)
SC: Seismology [S]
MN: Fall Meeting 2005