A hybrid deterministic and stochastic approach for tsunami hazard assessment in Iquique, Chile
A hybrid deterministic and stochastic approach for tsunami hazard assessment in Iquique, Chile
复制标题
智利伊基克海啸灾害评估的混合确定性和随机方法
作者：
Juan González;G. González;R. Aránguiz;D. Melgar;N. Zamora;M. Shrivastava;R. Das;P. Catalán;R. Cienfuegos
秘鲁南部和智利北方沿海地区是一个活跃的俯冲带，包含东太平洋海盆（~ 17°S-~ 24°S）最重要的地震空区之一。虽然2014年伊基克8.1级地震部分填补了差距，但在不久的将来仍有很高的孕震潜力释放一个Mw ~ 9地震，因此，该地区所有近场沿海城市都面临潜在的海啸威胁。在这篇文章中，我们提出了一个混合确定性-随机多情景的方法来评估目前的海啸灾害水平在伊基克市，一个重要的商业和工业中心的北方智利，是家庭的184,000居民。在我们的方法中，我们定义了400个随机的，10个确定性的和10个均匀的海啸地震场景，覆盖了整个地区的地震空白。根据重力异常的区域分布和已发表的震间耦合分布，我们解释了地震空区俯冲界面上四个主要凹凸体的出现。凹凸图案被用来构建一组确定性的滑动赤字震源的地震震级之间的Mw8.4和Mw8.9。此外，我们构建了10个均匀滑动的情况下，产生海啸灾害的淹没基线。随后，遵循随机方案，我们实施了Karhunen-Loève展开，以生成与确定性滑动亏损源相同震级范围内的400个随机地震情景。所有的来源被用来作为地震的情况下，模拟海啸的传播和淹没的非流体静力学模型（Neowave 2D）与经典的嵌套计划的伊基克市。我们获得了高分辨率的流深，沿海表面流和海平面高程数据。结果表明，峰值滑移位置和陆架共振在计算的海岸流深度中起重要作用。对整个模拟随机地震情景的分析表明，伊基克的最坏情况是M w 8.9地震。这种情况下，海啸到达时间约为12分钟，这对疏散过程至关重要。此外，最大波高和海啸流深度分别为~ 10 m和~ 24 m。所观察到的海岸共振过程表现出至少三个破坏性的海啸波列。根据历史和仪器目录统计数据，伊基克（Mw 8.9）可信的最坏情况地震情景的重现时间为395年，未来50年发生概率为11.86%。
The southern Peru and northern Chile coastal region is an active subduction zone that contains one of the most significant seismic gaps in the eastern Pacific basin (~ 17°S–~ 24°S). Although the gap was partially filled by the 2014 M w 8.1 Iquique earthquake, there is still a high seismogenic potential to release a M w ~ 9 earthquake in the near future; therefore, all the near-field coastal cities in the region face a latent tsunami threat. In this article, we propose a hybrid deterministic–stochastic multi-scenario approach to assess the current tsunami hazard level in the city of Iquique, an important commercial and industrial center of northern Chile that is home to 184,000 inhabitants. In our approach, we defined 400 stochastic, 10 deterministic and 10 homogeneous tsunamigenic earthquake scenarios, covering the entire area of the seismic gap. Based on the regional distribution of gravity anomalies and published interseismic coupling distributions, we interpreted the occurrence of four major asperities in the subduction interface of the seismic gap. The asperity pattern was used to construct a group of deterministic slip-deficit earthquake sources with seismic magnitudes ranging between M w 8.4 and M w 8.9. Additionally, we constructed 10 homogeneous slip scenarios to generate an inundation baseline for the tsunami hazard. Subsequently, following a stochastic scheme, we implemented a Karhunen–Loève expansion to generate 400 stochastic earthquake scenarios within the same magnitude range as the deterministic slip-deficit sources. All sources were used as earthquake scenarios to simulate the tsunami propagation and inundation by means of a non-hydrostatic model (Neowave 2D) with a classical nesting scheme for the city of Iquique. We obtained high-resolution data for flow depth, coastal surface currents and sea level elevation. The results suggest that the peak slip location and shelf resonance play an important role in the calculated coastal flow depths. The analysis of the entire set of simulated stochastic earthquake scenarios indicates that the worst-case scenario for Iquique is a M w 8.9 earthquake. This scenario presented a tsunami arrival time of ~ 12 min, which is critical for the evacuation process. In addition, the maximum wave height and tsunami flow depth were found to be ~ 10 m and ~ 24 m, respectively. The observed coastal resonance processes exhibit at least three destructive tsunami wave trains. Based on historical and instrumental catalog statistics, the recurrence time of the credible worst-case earthquake scenario for Iquique ( M w 8.9) is 395 years, with a probability of occurrence of ~ 11.86% in the next 50 years.
登录
查看更多内容
影响因子：
18.3
作者：
Lorito, S.;Romano, F.;Piatanesi, A.
通讯作者：
Piatanesi, A.
影响因子：
64.8
作者：
Schurr, Bernd;Asch, Guenter;Vilotte, Jean-Pierre
通讯作者：
Vilotte, Jean-Pierre
影响因子：
3.9
作者：
Hoffmann, Felix;Metzger, Sabrina;Oncken, Onno
通讯作者：
Oncken, Onno
影响因子：
2.8
作者：
S. Peyrat;R. Madariaga;E. Buforn;J. Campos;G. Asch;J. Vilotte
通讯作者：
S. Peyrat;R. Madariaga;E. Buforn;J. Campos;G. Asch;J. Vilotte