Japan Geoscience Union Meeting 2015

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Symbol S (Solid Earth Sciences) » S-CG Complex & General

[S-CG57] Structure, evolution and dynamics of mobile belts

Thu. May 28, 2015 11:00 AM - 12:45 PM IC (2F)

Convener:*Toru Takeshita(Department of Natural History Sciences, Graduate School of Science, Hokkaido University), Hiroshi Sato(Earthquake Prediction Research Center, Earthquake Research Institute, The University of Tokyo), Koichiro Obana(Research and Development Center for Earthquake and Tsunami, Japan Agency for Marine-Earth Science and Technology), Takuya NISHIMURA(Disaster Prevention Research Institute, Kyoto University), Yukitoshi Fukahata(Disaster Prevention Research Institute, Kyoto University), Aitaro Kato(Graduate School of Environmental Studies, Nagoya University), Jun Muto(Department of Earth Sciences, Tohoku University), Katsushi Sato(Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University), Shuichi Kodaira(Institute for Research on Earth Evolution Japan Agency for Marine-Earth Science and Technology), Takeshi Sagiya(Disaster Mitigation Research Center, Nagoya University), Tatsuya Ishiyama(Earthquake Research Institute, University of Tokyo), Makoto MATSUBARA(National Research Institute for Earth Science and Disaster Prevention), Yasutaka Ikeda(Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo), Chair:Tohru Watanabe(Gradudate School of Science and Engineering, University of Toyama)

11:45 AM - 12:00 PM

[SCG57-20] Development of fault activity in Japan estimated from the response of the faults to the tectonic stress field

*Ayumu MIYAKAWA1, Makoto OTSUBO2 (1.Institute of Geology and Geoinformation (IGG), Geological Survey of Japan, AIST, 2.National Institute of Advanced Industrial Science and Technology (AIST), Institute of Earthquake and)

Keywords:crustal deformation processes, tectonic zone, fault acitivity

The regional tectonic stress of the NE Japan arc continues from around 3.5 Ma to present (Sato, 1994). On the other hand, the initiation age of active faulting increased after 1.5 Ma (Doke et al., 2012). These results suggests that the response of the fault activity to the tectonic stress field takes long time (i.e. a few Ma). Then we study the maturity of the response of the fault activity to the regional tectonic stress field. In this study, we discuss the maturity of the field according to the present stress field and the present fault activity with the geodetic and geologic deformation.

The regional tectonic stress was estimated from the focal mechanisms of F-net by stress tensor inversion. The responses of the active faults and geological faults to the tectonic stress are calculated by using the slip tendency (Morris et al., 1996). The calculation results show that the most of high activity faults becomes active faults in the Tohoku region. On the other hand, some high activity faults have been geological faults in the Chubu and Kinki region. This difference of the response of faults to the tectonic stress in different regions is coherent with the geodetic and geologic deformation.

Sato, H. The relationship between late Cenozoic tectonic events and stress field and basin development in northeast Japan Journal of Geophysical Research, 1994, 99, 22261-22274
Doke, R et al. Spatial patterns of initiation ages of active faulting in the Japanese Islands. Active Fault Research, 2012, 37: 1-15.
Morris, A.; Ferrill, D. & Henderson, D. Slip-tendency analysis and fault reactivation Geology, 1996, 24, 275-278