Japan Geoscience Union Meeting 2016

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Poster

Symbol S (Solid Earth Sciences) » S-SS Seismology

[S-SS31] Active faults and paleoseismology

Mon. May 23, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Mamoru Koarai(Earth Science course, College of Science, Ibaraki University), Hisao Kondo(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Ken-ichi Yasue(Japan Atomic Energy Agency), Hideaki Goto(Graduate school of letters, Hiroshima University)

5:15 PM - 6:30 PM

[SSS31-P02] Paleoseismological study on subsidiary surface fault ruptures produced by the 2014 Mw 6.2 Northern Nagano earthquake, central Japan: Preliminary report

*Keiichi Ueta1, Kotarou Aiyama1, Toshinori Sasaki1, Masaru SATO2, Kiyoshi Ichikawa2, Takenobu Tanaka2 (1.Central Research Institute of Electric Power Industry, 2.Hanshin Consultants)

The 2014 Mw 6.2 Northern Nagano earthquake (central Japan) produced a 10 km long surface rupture zone that consists of main rupture and subsidiary ruptures. We carried out trench excavation surveys on the subsidiary ruptures to reveal paleoseismic activities. Reverse faults cutting bedrock and terrace deposits were exposed on the trench walls. Judging from upward fault termination and other deformation structures, we identified three paleoearthquake events. The timing of these events is still under way.