ABSTRACT This study conducts a probabilistic tsunami hazard assessment (PTHA) and compares two approaches to representing earthquake source variability in the PTHA. The target region is the coast of Zihuatanejo in the State of Guerrero, Mexico. First, numerous synthetic fault slip distributions are generated using a stochastic random-phase process. The moment magnitude ranges from 7.8 to 8.6. A numerical tsunami simulation is implemented for each earthquake fault slip. The result of the Monte Carlo simulation indicates the tsunami heights at the nearshore of city areas tend to be higher. Then, the exceedance probabilities of tsunami height are estimated and compared using two different PTHA approaches: the random phase approach and the logic tree approach. The logic tree can generally incorporate many types of uncertainty, but this study focuses on the earthquake source uncertainty for comparison. The comparison result indicates significant differences between the two tsunami hazard models. Additionally, the logic tree approach is used to investigate the possible ranges in tsunami heights for extreme events by assuming that a sizable epistemic uncertainty exists in a given region. The tsunami heights for a 1,000-year event vary significantly when the weighting values for the paths in the logic tree are changed.

中文翻译：

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由于海啸变异性的表现，芝华塔尼欧（墨西哥）的概率海啸灾害评估的不确定性

摘要 本研究进行了概率海啸灾害评估 (PTHA)，并比较了两种表示 PTHA 中地震源变异性的方法。目标区域是墨西哥格雷罗州的芝华塔尼欧海岸。首先，使用随机随机相位过程生成大量合成断层滑动分布。力矩大小范围从 7.8 到 8.6。对每个地震断层滑动进行数值海啸模拟。蒙特卡罗模拟的结果表明，城市地区近岸的海啸高度往往更高。然后，使用两种不同的 PTHA 方法估计和比较海啸高度的超越概率：随机相位方法和逻辑树方法。逻辑树通常可以包含多种类型的不确定性，但本研究侧重于震源不确定性进行比较。比较结果表明两种海啸灾害模型之间存在显着差异。此外，逻辑树方法用于通过假设给定区域存在相当大的认知不确定性来研究极端事件海啸高度的可能范围。当逻辑树中路径的权重值发生变化时，1000 年事件的海啸高度会发生显着变化。