New insights of tsunami hazard from the 2011 Tohoku-oki event

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• 作者：Kazuhisa Goto^a ; ^b ; ^{kgoto@perc.it-chiba.ac.jp} ; Catherine Chagu&eacute ; -Goff^c ; ^d ; Shigehiro Fujino^e ; James Goff^c ; Bruce Jaffe^f ; Yuichi Nishimura^g ; Bruce Richmond^f ; Daisuke Sugawara^b ; Witold Szczuci¨½ski^h ; David R. Tappinⁱ ; Robert C. Witter^j ; Eko Yulianto^k
• 关键词：Tsunami deposits ; Tohoku-oki tsunami ; Japan
• 刊名：Marine Geology
• 出版年：2011
• 出版时间：1 December, 2011
• 年：2011
• 卷：290
• 期：1-4
• 页码：46-50
• 全文大小：1069 K

文摘

We report initial results from our recent field survey documenting the inundation and resultant deposits of the 2011 Tohoku-oki tsunami from Sendai Plain, Japan. The tsunami inundated up to 4.5 km inland but the > 0.5 cm-thick sand deposit extended only 2.8 km (62 % of the inundation distance). The deposit however continued as a mud layer to the inundation limit. The mud deposit contained high concentrations of water-leachable chloride and we conclude that geochemical markers and microfossil data may prove to be useful in identifying the maximum inundation limit of paleotsunamis that could extend well beyond any preserved sand layer. Our newly acquired data on the 2011 event suggest that previous estimates of paleotsunamis (e.g. 869 AD J¨­gan earthquake and tsunami) in this area have probably been underestimated. If the 2011 and 869 AD events are indeed comparable, the risk from these natural hazards in Japan is much greater than previously recognized.