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TSUNAMI GENERATION WITHOUT SHAKING DUE TO EARTHQUAKES.

不会因地震而产生海啸。

基本信息

批准号：
05452370
负责人：
SHUTO Nobuo
金额：
$ 2.82万
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 (B)
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-05452370/
关键词：
Non-seismic tsunami generation Tsunami generated by a secondary fault Tsunami generation due to volcanic eruption 1983 Nihonkai-Chubu earthquake tsunami 1992 Nicaraguan tsunami 1993 Hokkaido Nansei-oki earthquake tsunami 1883 Krakatau tsunami

项目摘要

A tsunami is ususlly considered to be generated by an earthquake. Once fault parameters are given, the initial tsunami profile is calculated with the elastic theory. It is assumed that the vertical displacement of sea bottom is closely related to the fault movement. However, this assumption is not always true.1) In case of the 1983 Nihonkai-Chubu earthquake composed of two faults, a secondary fault in the north fault and a non-seismic movement are necessary in order to explain earlier arrival of the actual tsunami than the computed tsunami for the major fault movement determined by seismic data.2) In case of the 1992 Nicaraguan tsunami, in spite of a large tsunami, the earthquake was very weak, as 2 in the JMA intensity scale. Whether this tsunami was generated by the earthquake or by other mechanism was examined. It is concluded that this earthquake was a tsunami earthquake.3) In case of the 1993 Hokkaido Nansei-oki earthquake, the first tsunami arrived at the western coast of Hokkaido 5 minutes faster than that generated at the place of the fault estimated from seismic data. This strongly suggests that other tsunami generation mechanism than the earthquake should be found in the area between the fault and the coast.4)The 1883 Krakatau tsunami which was not generated by an earthquake but by a caldera formation was numerically simulated. A method is developed to stably simulate a sudden fall of water at the initial profile.

海啸通常被认为是由地震引起的。一旦给出了断层参数，就可以利用弹性理论计算初始海啸剖面。推测海底垂直位移与断层运动密切相关。然而，这种假设并不总是正确。1) 在 1983 年日本海中部地震由两条断层组成的情况下，为了解释实际海啸比由地震数据确定的主要断层运动计算出的海啸更早到达，需要北断层中的次生断层和非地震运动。2) 在 1992 年尼加拉瓜海啸的情况下，尽管海啸时，地震非常弱，JMA 烈度为 2 级。这次海啸是由地震还是其他机制引起的进行了检查。结论是这次地震是海啸地震。3)在1993年北海道南西大地震中，第一次海啸到达北海道西海岸的速度比地震数据估计的断层处产生的海啸要快5分钟。这强烈表明在断层和海岸之间的区域应该发现地震以外的其他海啸发生机制。4)对1883年的喀拉喀托海啸进行了数值模拟，该海啸不是由地震而是由火山口形成引起的。开发了一种方法来稳定地模拟初始剖面处的水突然落下。