Historical tsunamis and storms recorded in a coastal lowland,Shizuoka Prefecture,along the Pacific Coast of Japan |
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Authors: | JUNKO KOMATSUBARA OSAMU FUJIWARA KEITA TAKADA YUKI SAWAI THAN TIN AUNG TAKANOBU KAMATAKI |
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Affiliation: | 1. National Institute of Advanced Industrial Science and Technology, Geological Survey of Japan, Central 7, Higashi 1‐1‐1, Tsukuba, Ibaraki 305‐8567, Japan (E‐mail: j.komatsubara@aist.go.jp);2. Fukken Co. Ltd, Hikarimachi 2‐10‐11, Higashi‐ku, Hiroshima 732‐0052, Japan;3. Oyo Corporation, Daitakubo 2‐2‐19, Minami‐ku, Saitama 336‐0015, Japan Associate Editor: Maarten Kleinhans |
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Abstract: | Four sand units deposited by tsunamis and one sand unit deposited by storm surge(s) were identified in a muddy marsh succession in a narrow coastal lowland along the Pacific coast of central Japan. Tsunamis in ad 1498, 1605, 1707 and 1854 that were related to large subduction‐zone earthquakes along the Nankai Trough, and storm surges in 1680 and/or 1699 were responsible for the deposition of these sand units. These sand units are distinguished by lithofacies, sedimentary structures, grain‐size and mineral composition, and radiocarbon ages; their ages are supported by events in local historical records. The tsunami deposits in the study area are massive or parallel‐laminated sands, with associated intraclasts, gravels, draping mud layers and, rarely, a return‐flow subunit. The storm surge deposits are devoid of these characteristics, and are composed of groups of thin, current ripple‐laminated sand layers. The differences in sedimentary structures between the tsunami and storm surge deposits are attributed to the different characteristics of tsunami and storm waves. |
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Keywords: | Central Japan Geoslicer Nankai Trough Shirasuka storm deposit tsunami deposit |
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