Earthquake related tsunami hazard along the western coast of Thailand
Earthquake related tsunami hazard along the western coast of Thailand
复制标题
泰国西海岸与地震有关的海啸灾害
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
G. Pedersen
中科院分区：
文献类型：
--
作者：
F. Løvholt;H. Bungum;C. Harbitz;S. Glimsdal;C. Lindholm;G. Pedersen
抽象的。本研究的主要背景是一个项目，旨在协助泰国当局在 2004 年 12 月 26 日发生毁灭性的苏门答腊-安达曼地震和海啸之后，制定如何从短期和长期角度应对未来海啸风险的计划。该研究的重点是定义和分析一系列未来可能发生的地震情景（震级 8.5、8.0 和 7.5）以及相关的重现期，每种地震情景都伴随着特定的海啸模型。 2004 年海啸波在泰国西海岸受影响最严重的地区造成最高水位比平均海平面高出 5 至 15 m。这些水平及其空间分布已通过详细的数值模拟得到证实。所应用的地震源是根据现有的地震学和大地测量反演开发的，并且使用该源作为初始条件的模拟与海平面记录和上升观测非常吻合。研究得出的结论是，另一场影响泰国西部海岸线并引发海啸的大型逆冲地震在数百年内不太可能再次发生。这部分是基于这样的假设，即锡默卢群岛附近的南安达曼微板块边界构成了一个地质屏障，将阻止其发生重大破裂，部分是基于班达阿什地区以北俯冲率下降。还得出的结论是，沿巽他-安达曼弧部分准备应对的可能影响泰国的最大可信地震是未来 50-100 年内发生的 8.5 级地震，预计发生的地震将比巨型逆冲事件发生更多的空间和时间不规则性。数值模拟显示，此类地震会引发泰国西海岸最高水位高达 1.5-2.0 m 的海啸，高潮时水位可能达到 2.5-3.0 m。然而，从更长的时间来看（比如超过50-100年），发生与2004年事件类似震级和后果的地震的可能性将逐渐增大，并最终构成不可接受的社会风险。这些结论仅适用于泰国，因为同一地区发生的 8.5 级地震对苏门答腊岛西北部、安达曼和尼科巴群岛，甚至斯里兰卡和印度海岸线部分地区的影响可能更严重。此外，沿着巽他弧线进一步向南，目前发生大规模破裂的可能性比 2004 年 12 月 26 日发生破裂的地区要高得多。
Abstract. The primary background for the present study was a project to assist the authorities in Thailand with development of plans for how to deal with the future tsunami risk in both short and long term perspectives, in the wake of the devastating 26 December 2004 Sumatra-Andaman earthquake and tsunami. The study is focussed on defining and analyzing a number of possible future earthquake scenarios (magnitudes 8.5, 8.0 and 7.5) with associated return periods, each one accompanied by specific tsunami modelling. Along the most affected part of the western coast of Thailand, the 2004 tsunami wave caused a maximum water level ranging from 5 to 15 m above mean sea level. These levels and their spatial distributions have been confirmed by detailed numerical simulations. The applied earthquake source is developed based on available seismological and geodetic inversions, and the simulation using the source as initial condition agree well with sea level records and run-up observations. A conclusion from the study is that another megathrust earthquake generating a tsunami affecting the coastline of western Thailand is not likely to occur again for several hundred years. This is in part based on the assumption that the Southern Andaman Microplate Boundary near the Simeulue Islands constitutes a geologic barrier that will prohibit significant rupture across it, and in part on the decreasing subduction rates north of the Banda Ache region. It is also concluded that the largest credible earthquake to be prepared for along the part of the Sunda-Andaman arc that could affect Thailand, is within the next 50–100 years an earthquake of magnitude 8.5, which is expected to occur with more spatial and temporal irregularity than the megathrust events. Numerical simulations have shown such earthquakes to cause tsunamis with maximum water levels up to 1.5–2.0 m along the western coast of Thailand, possibly 2.5–3.0 m on a high tide. However, in a longer time perspective (say more than 50–100 years) the potentials for earthquakes of similar magnitude and consequences as the 2004 event will become gradually larger and eventually posing an unacceptable societal risk. These conclusions apply only to Thailand, since the effects of an M 8.5 earthquake in the same region could be worse for north-western Sumatra, the Andaman and Nicobar Islands, maybe even for Sri Lanka and parts of the Indian coastline. Moreover, further south along the Sunda arc the potentials for large ruptures are now much higher than for the region that ruptured on 26 December 2004.