HR: 09:25h
AN: T51A-06 INVITED     [PDF]
TI: Water-weakened lower crust and its role in the concentrated deformation in the Japanese islands
AU: * Iio, Y
EM: iio@rcep.dpri.kyoto-u.ac.jp
AF: Disater Prevention Research Institute, Kyoto University, Gokasho, Uji, 611-0011 Japan
AU: Sagiya, T
EM: sagiya@seis.nagoya-u.ac.jp
AF: Nagoya University, Furou-cho,Tikusa-ku,, Nagoya, 464-8602 Japan
AU: Kobayashi, Y
EM: iio@rcep.dpri.kyoto-u.ac.jp
AF: Institute for Geoscience, University of Tsukuba, Tennoudai 1-1, Tsukuba, 305-0006 Japan
AU: Shiozaki, I
EM: shiozaki@cv.tottori-u.ac.jp
AF: Institute for Geoscience, Tottori University, 4-101 Minami, Koyama-cho, Tottori, 680-8552 Japan
AB: The nature and origin of the concentrated deformation zone along the Japan Sea coast (NKTZ: Niigata-Kobe Tectonic Zone) was investigated by carefully analyzing the GPS data and qualitatively modeling the lower crust in NKTZ. It was concluded that this deformation zone is not a plate boundary between the Amurian plate (AMU) and the North America plate but is rather an internal deformation zone near the eastern margin of AMU. The data previously obtained on the conductivity anomalies in the lower crust and the 3He/4He ratios suggest that the concentrated deformation in NKTZ results from the lower crust in NKTZ being weakened by a high water content. The high water content is thought to result from the dehydration of subducting slabs.
DE: 7200 SEISMOLOGY
DE: 7209 Earthquake dynamics and mechanics
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
SC: Tectonophysics [T]
MN: 2003 Fall Meeting