Tsunami deposits in a lacustrine sequence of the Sanriku coast

三陆海岸湖泊序列中的海啸沉积物

• 批准号: 05640492
• 负责人: MINOURA Koji
• 金额: $ 1.34万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05640492/
• 关键词: lacustrine pond; tsunami; seawater ingredients; carbonates; pore water; subduction zones; earthquake; historical material; 三陸; 地震; 海浜湖沼; 海岸過程

Marine sand layr in a succession of lacustrine deposits, together with interstitial carbonates and pore water rich in seawater ingredients within sand layr, is distinct evidence for tunami-genic sedimentation. Thirteen thin sand layrs were found to be intercalated within pond deposits of the Sanriku coast. Detailed sedimentological and geochemical work demonstrates that the sand layr were laid down as a result of tsunamis. The dates of these tsunami deposits are mostly equivalent to the ages of the moderate to severe ancient tusnamis documented in historical materials, suggesting that tsunamis with waves having reached a maximum height of more than 1 m on the coast caused net sediment tranbsport landward and accumulated thin sand beds in the pond.The estimation of potential hazards to coastal zones afforded by tsunamis is especially important, and an accurate knowledge of the frequency of destructive tsunamis is essential for assessment of the hydro-engineering security of high risk facilities such as coastal nuclear power stations. There is a pressing need for learning more about earthquake initiation in and around subduction zones. The methods adopted here can be applied to other coastal areas in the active margin, and may provide useful information on the risks of tsunamis.

一系列湖相沉积中的海相砂层，以及砂层中富含海水成分的间隙碳酸盐和孔隙水，是金枪鱼成因沉积的明显证据。在三陆海岸的池塘沉积物中发现了13个薄砂层。详细的沉积学和地球化学研究表明，沙层是海啸造成的。这些海啸沉积的年代大多相当于史料中记载的中到重度古代尖牙的年龄，这表明海啸在海岸的最大高度已达1米以上，造成净沉积物向陆地迁移，并在池塘中堆积薄薄的沙床。估计海啸对沿海地区的潜在危险特别重要，准确了解破坏性海啸的频率对于评估沿海核电站等高风险设施的水利工程安全至关重要。迫切需要更多地了解俯冲带内部和周围的地震引发情况。这里采用的方法可以应用于活动边缘的其他沿海地区，并可能提供有关海啸风险的有用信息。

项目成果

Minoura, k.et.al.: "Sequence of sedimentation processes caused by the 1992 Flores tsunami:Evidence from Babi Island" Geology. vol.25. 523-526 (1997)

Minoura, k.et.al.：“1992 年弗洛勒斯海啸引起的沉积过程序列：来自巴比岛的证据”地质学。

K.Minoura & T.Nabata: "Discovery of ancient tsunami deposit in wastal sequences of southwest Japan:Veribication of a louge historictsunami" The Island Arc. V.3(印刷中). (1994)

K.Minoura 和 T.Nabata：“在日本西南部荒地序列中发现古代海啸沉积物：历史性海啸的验证”The Island Arc V.3（出版中）。

Minoura, K.et.al.: "Tsunami sedimentation associated with the 1923 Kamchatka earthquake" Sedimentary Geology. vol.106. 145-154 (1996)

Minoura, K.et.al.：“与 1923 年堪察加地震相关的海啸沉积”沉积地质学。

Minoura, K., Gusiakov, V.G., and Svendsen, J.I.: "Effect of fallen snow on run-up processes of the 1923 Kamchatka Tsunami. Abstracts of the 1994 Western Pacific" Geophysics Meeting (American Geophysical Union). Hong Kong, July 25-29. 11 (1994)

Minoura, K.、Gusiakov, V.G. 和 Svendsen, J.I.：“降雪对 1923 年堪察加海啸的助跑过程的影响。1994 年西太平洋摘要”地球物理学会议（美国地球物理联盟）。

箕浦 幸治: "箕浦幸治編「青森県の地質」青森県の津波災害" 青森県, 207 (1998)

箕浦浩二：《青森县地质》青森县海啸灾难，青森县箕浦浩二编，207（1998）