2026-03-07T00:35:18Z https://repository.dl.itc.u-tokyo.ac.jp/oai

oai:repository.dl.itc.u-tokyo.ac.jp:00032427 2022-12-19T04:08:29Z 80:4535:4569:4573 9:504:4538:4571:4574

Resurvey of Possible Seismic Fissures in the Old-Edo River in Tokyo 旧江戸川で見いだされた地震痕跡の再調査 島崎, 邦彦 72751 原口, 強 72752 石辺, 岳男 72753 中田, 高 72754 51.3 Geo-Slicer Liquefaction slumping traces the Old-Edo River Geo-slicer sampling of riverbed strata, boring sampling of riverside strata, single-channel seismic reflection survey, and electric survey were carried out to understand the causes of ground fissures and ruptures with a vertical dislocation of 25cm found by Shimazaki and others beneath the Old-Edo River in Tokyo in 1997. We concluded that fissures and ruptures were caused by gravity slumping due to liquefaction taking place near a paleo-valley, which was found by the reflection survey to run across the Old-Edo River. In the 1997 survey, at least two liquefaction and slumping events, probably corresponding to two large earthquakes, were identified from a Geoslicer sample down to about 8m in depth. Their ages were reported as after 1800yBP and 2900－3700yBP, respectively. Dating results for new samples obtained in this study are consistent with previous estimates. departmental bulletin paper 東京大学地震研究所 2009 application/pdf 東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo 3 84 229 240 AN00162258 00408972 https://repository.dl.itc.u-tokyo.ac.jp/record/32427/files/IHO84302.pdf https://doi.org/10.15083/0000032427 http://hdl.handle.net/2261/35904 https://repository.dl.itc.u-tokyo.ac.jp/records/32427 jpn