An improvement of tsunami hazard analysis in Central Chile based on stochastic rupture scenarios
An improvement of tsunami hazard analysis in Central Chile based on stochastic rupture scenarios
复制标题
基于随机破裂情景的智利中部海啸灾害分析的改进
DOI：
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发表时间：
2020
影响因子：
2.4
通讯作者：
R. Benavente
中科院分区：
文献类型：
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作者：
Ignacio Becerra;R. Aránguiz;Juan González;R. Benavente
摘要智利中部地区是海啸灾害的多发区，近500年来多次发生大地震和海啸。智利的海啸危险性分析传统上是通过确定性方法进行的，这种方法基于历史事件和均匀滑动分布。本研究的目的是改善智利中部（30°S至38°S）的海啸灾害分析。为了涵盖这一目的，产生了8.8至9.2级的随机地震情景。通过随机降阶模型（SROM）选择了两组不同的随机海啸情景，并将其应用于Quintero湾进行概率海啸危险性分析（PTHA）。结果表明，随机海啸情景下的金特罗湾PTHA与海湾的古海啸记录一致，而确定性海啸情景低估了灾害。两组（50和100情景，分别）给出了类似的结果时，较小的重现期进行了分析。然而，对于较大的重现期（2000年）的一组100方案显示出更好的结果与以前的古地震学研究结果一致。这里实施的方法可以复制在智利的其他地震区，以及在其他活跃的俯冲带，因此，近场和远场事件都可以分析。
ABSTRACT Central Chile is exposed to tsunami hazard, and large earthquakes and tsunamis have occurred over the last 500 years. Tsunami hazard analysis in Chile has been traditionally implemented by means of a deterministic approach, which is based on historical events and uniform slip distribution. The objective of the present study is to improve tsunami hazard analysis in central Chile (30°S to 38°S). To encompass the purpose, stochastic earthquake scenarios of magnitude 8.8 to 9.2 were generated. Two different sets of stochastic tsunami scenarios were selected by means of the Stochastic Reduced Order Model (SROM), which were applied to Quintero bay to perform a Probabilistic Tsunami Hazard Analysis (PTHA). The results showed that PTHA of Quintero bay from stochastic tsunami scenarios agrees with paleotsunami records in the bay, while a deterministic tsunami scenario underestimated the hazard. Two sets (50 and 100 scenarios, respectively) give similar results when smaller return periods are analyzed. However, for larger return periods ( 2000 yr) the set of 100 scenarios show better results consistent with previous paleoseismological findings. The methodology implemented here can be replicated in other seismic regions in Chile as well as in other active subduction zones, thus, both near field and far field events can be analyzed.