冲绳海槽地区地震潜在海啸对中国东南沿海的影响研究

Impact of potential tsunami induced by Okinawa trough earthquakes on southeastern seaboard of China

采用球坐标系下非线性浅水波方程,研究日本本州M9.0大地震引发的海啸对中国东南沿海的影响,并计算了冲绳海槽构造带上3个不同段落可能发生潜在地震引发的海啸,分析这些海啸与日本大海啸的浪高和走时关系.结果表明,日本地震海啸模拟结果与日本当地报道及中国东南沿海7个验潮站的报道结果相符.冲绳海槽构造带中段可能发生的3次不同震级(M7.0,M7.5,M8.0)潜在地震引发的海啸到达中国东南沿海的时间比日本海啸提前约4个小时,从震源区传播3个多小时即可到达华东沿海部分验潮站.冲绳海槽M7.5潜在地震海啸在验潮站上计算的波高与日本海啸相当,中冲绳海槽M8.0潜在地震海啸在大陈站的波高将超过0.9m,在坎门站波高将超过1.8m.北冲绳海槽的潜在地震海啸威胁主要集中在江苏盐城、上海一带,南冲绳海啸主要对台湾东北部和浙江沿海产生威胁.本文对冲绳海槽构造带上潜在地震引发海啸的模拟结果,可为中国东南沿海地区的防震减灾、海啸预警提供有意义的参考.

Utilizing spherical nonlinear shallow water equation this paper studies the impact of the 11 March 2011 Japan M9.0 earthquake tsunami on southeastern seaboard region of China,and calculates potential tsunamis induced by strong earthquakes in three different sections of Okinawa trough.Then the relation between wave heights and arrival times of the Japan tsunami and the simulated tsunamis is analyzed.The result indicates that the simulated Japan tsunami is consistent with local reports of Japan and the repots from 7 tide gauge stations on coastal line of southeastern China.The arrival times of the tsunamis induced by three different magnitude（M7.0,M7.5,M8.0） potential earthquakes in middle Okinawa trough would be 4 hours earlier than that of the Japan tsunami.The tsunami generated in middle Okinawa trough would take about 3 hours to reach some gauge stations on coastal line of eastern China.The wave heights at the gauge stations induced by an M7.5 earthquake tsunami in middle Okinawa trough are nearly the same as the wave height generated by the Japan M9.0 earthquake tsunami.The tsunami aroused by an M8.0 earthquake in middle Okinawa trough would produce about 0.9 m wave height at Dachen tide gauge station,and higher than 1.8 m at Kanmen station.The potential tsunami hazard caused by the earthquakes in northern Okinawa trough would mainly impact the seaboard of Yancheng,Jiangsu province,and Shanghai.Potential tsunami hazard aroused by earthquakes in southern Okinawa trough would mainly appear in northeastern seaboard of Taiwan province and southeastern seaboard of Zhejiang province.The simulation result of potential tsunami in Okinawa trough tectonic belt provides a valuable reference for earthquake and tsunami hazard mitigation and precaution in southeastern China seaboard.