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SEGMENTIOLOGICAL STUDY OF MATERIAL TRANSPORT BY TSUNAMIS

海啸物质运输的分段研究

基本信息

批准号：
13480116
负责人：
MINOURA Koji
金额：
$ 11.39万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

Tsunamis have great hydrodynamic energy and have distinctive hydrodynamic effects on coastal regions. Recent geological studies have shown that a record of a tsunami inundation of a coast is preserved in tsunami deposits. Tsunamis transport large amounts of marine water and sediments inland, and seawater and sand invade coastal lakes and marshes. Moreover, tsunamis often move masses of rocks (Imamura et al., 2001), forming great onshore mounds or submarine bars. To interpret such tsunami records and estimate their ages, we must identify and study tsunami deposits. For example, multiple marine sand deposits found in excavations along the coast of northeast Japan suggest that repeated prehistoric and historic tsunami inundations affected the development of the coastal plain throughout the late Holocene (Minoura and Nakaya, 1991). However, the mechanisms of material transport -including the accumulation of thick mounds of marine sand and large-scale movement of huge rocks -by tsunamis are still unclear. Moreover, the topographic and geologic effects of tsunami sedimentation have never been fully considered, and the technological evaluation of tsunami sedimentation from the viewpoint of the impact on people and disaster planning is still insufficient. It has also been thought that earth-science methods cannot be applied to the study of tsunami deposits. In this context, many scientists, engineers, and historiographers have recently started coordinated studies on the recognition of tsunami deposits and on tsunami-induced material transport and environmental modification. Interdisciplinary studies of tsunami sedimentation will both clarify tsunami material transport mechanisms and establish criteria for theoretical understanding of the role of tsunamis in the development of coastal topography. The results of these studies will be applied to actual tsunami events, and will enable the specific disaster assessment of future tsunami inundations.

海啸具有巨大的水动力能量，对沿海地区具有独特的水动力效应。最近的地质研究表明，海啸淹没海岸的记录保存在海啸沉积物中。海啸将大量海水和沉积物输送到内陆，海水和沙子侵入沿海湖泊和沼泽。此外，海啸经常移动大量的岩石（Imamura等人，2001年），形成巨大的陆上土丘或海底沙洲。为了解释这些海啸记录并估计它们的年龄，我们必须识别和研究海啸沉积物。例如，在日本东北部沿着的挖掘中发现的多个海砂沉积物表明，在整个全新世晚期，重复的史前和历史海啸洪水影响了沿海平原的发展（Minoura和Nakaya，1991年）。然而，海啸造成的物质迁移机制--包括厚海沙堆的堆积和巨大岩石的大规模移动--仍不清楚。此外，海啸沉积的地形和地质影响从未得到充分考虑，从对人的影响和灾害规划的角度对海啸沉积进行的技术评估仍然不足。人们还认为，地球科学的方法不能应用于海啸沉积物的研究。在这方面，许多科学家、工程师和历史学家最近开始协调研究海啸沉积物的识别以及海啸引起的物质迁移和环境改变。海啸沉积的跨学科研究将澄清海啸物质的运输机制，并建立标准的海啸在沿海地形的发展中的作用的理论理解。这些研究的结果将应用于实际的海啸事件，并将有助于对未来的海啸洪水进行具体的灾害评估。