Japan Geoscience Union Meeting 2023

Presentation information

[J] Online Poster

S (Solid Earth Sciences ) » S-SS Seismology

[S-SS13] Active faults and paleoseismology

Tue. May 23, 2023 10:45 AM - 12:15 PM Online Poster Zoom Room (15) (Online Poster)

convener:Mamoru Koarai(Earth Science course, College of Science, Ibaraki University), Yoshiki Sato(Advanced Industrial Science and Technology, Geological Survey of Japan), Yoshiki Shirahama(Advanced Industrial Science and Technology, Geological Survey of Japan, Research Institute of Earthquake and Volcano Geology, Active Fault Research Group), Ken-ichi Yasue(University of Toyama)

On-site poster schedule(2023/5/22 17:15-18:45)

10:45 AM - 12:15 PM

[SSS13-P09] Deep seismic reflection profiling across the central portion of the Morimoto-Togashi fault zone, central Japan

*Tatsuya Ishiyama1, Hiroshi Sato1,5, Yoshihiro Hiramatsu2, Tomotaka Iwata3, Hideo Saito4, Hirokazu Ishige4, Susumu Abe4 (1.Earthquake Research Institute, University of Tokyo, 2.School of Geosciences and Civil Engineering, College of Science and Engineering, Kanazawa University, 3.Disaster Prevention Research Institute, Kyoto University, 4.JGI, Inc., 5.Center for Integrated Research and Education of Natural Hazards, Shizuoka University )

Keywords:Active fault, Deep seismic experiment, Morimoto-Togashi Fault Zone

To define subsurface fault geometry, structural characters of fault-related folds and their structural growth during Quaternary, we collected ca. 24 km long, onshore multi-channel deep seismic reflection data across the central portion of the Morimoto-Togashi Fault Zone (MTFZ), an active reverse fault system located in the southwest extension of the Toyama trough, by using four Enviro-vib trucks as seismic sources and more than 970 seismic channels. Seismic reflection processing reveals the detailed subsurface structure in accordance with P-wave velocity structures obtained by refraction tomography. The depth-converted section that was correlated with the local Neogene strata successfully shows a moderately east-dipping reverse fault plane that is overlain by a monocline of Miocene to Pleistocene sedimentary units. We will also briefly explore structural relationships of folded middle-late Pleistocene fluvial terraces along the MTFZ and the fault trajectories and the growth of the fault-related folds.

Acknowledgements: This work was supported by MEXT “Comprehensive Research Project for the Morimoto-Togashi Fault Zone”.