Japan Geoscience Union Meeting 2015

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Oral

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

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

Thu. May 28, 2015 4:15 PM - 6:00 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:Bunichiro Shibazaki(International Institute of Seismology and Earthquake Engineering, Building Research Institute)

4:30 PM - 4:45 PM

[SCG57-32] Why do horizontally shortening sedimentary basins subside?

*Yoshihisa IIO1 (1.DPRI., Kyoto Univ.)

Keywords:high strain region, stress, sedimentary basin, subsidence, intraplate earthquake, active fault

It is mysterious that horizontally shortening sedimentary basins subside. In the region shortened horizontally, it is possible that material excess occurs and that the crust becomes thicken. Then, the topography becomes high there. However, the sedimentary basins in Japan, for example, the Niigata and Osaka basins, are subsiding and also shortening. It is difficult to explain these phenomena by thrust faulting, since the amount of uplifts by thrust faulting on the hanging wall side is much smaller than that in the foot wall side. It is plausible that increasing differential stress due to subsidence accelerates horizontal shortening, since the vertical principal stress decreases by the subsidence.