Modeling the Sources of the 2018 Palu, Indonesia, Tsunami Using Videos From Social Media
Modeling the Sources of the 2018 Palu, Indonesia, Tsunami Using Videos From Social Media
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DOI：
10.1029/2019jb018675
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发表时间：
2020-03
期刊：
影响因子：
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通讯作者：
Ignacio Sepúlveda;J. Haase;M. Carvajal;Xiaohua Xu;P. Liu
中科院分区：
文献类型：
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作者：
Ignacio Sepúlveda;J. Haase;M. Carvajal;Xiaohua Xu;P. Liu
2018年帕卢海啸对相关7.5级地震造成的破坏起到了重要作用。这引发了一场辩论，这场中等规模的地震是如何在帕卢湾引发如此大的海啸的，海啸的落差超过10米。垂直同震变形和海底滑坡的大分量可能被认为是潜在的解释。然而，由于仪器数据的缺乏，很难确定这两种来源的潜在贡献。我们使用从帕卢湾的社交媒体视频中获得的海啸波形来模拟海啸的可能来源。我们用不同的断层几何形状来反演InSAR数据，并使用由此产生的海底位移来模拟海啸。同震源本身不能匹配视频导出的时间历史和测量的起伏。然后，我们使用视频导出的时间历史和潮汐计记录作为输入进行海啸震源反演。我们指定假设的滑坡位置并求解初始海啸海拔。我们的研究结果得到了调查结果的验证，表明帕卢湾南部有限数量的山体滑坡足以解释海啸数据。帕卢海啸凸显了用潮汐计准确捕捉可能对海岸产生巨大影响的短周期海浪的振幅和时间的困难。山体滑坡与高断层滑动位置的接近也表明，走滑环境中的海啸危害评估应包括触发的山体滑坡，特别是对于海岸线形态与断层几何形状密切相关的地区。
The 2018 Palu tsunami contributed significantly to the devastation caused by the associated MW 7.5 earthquake. This began a debate about how the moderate size earthquake triggered such a large tsunami within Palu Bay, with runups of more than 10 m. The possibility of a large component of vertical coseismic deformation and submarine landslides have been considered as potential explanations. However, scarce instrumental data have made it difficult to resolve the potential contributions from either type of source. We use tsunami waveforms derived from social media videos in Palu Bay to model the possible sources of the tsunami. We invert InSAR data with different fault geometries and use the resulting seafloor displacements to simulate tsunamis. The coseismic sources alone cannot match both the video‐derived time histories and surveyed runups. Then we conduct a tsunami source inversion using the video‐derived time histories and a tide gauge record as inputs. We specify hypothetical landslide locations and solve for initial tsunami elevation. Our results, validated with surveyed runups, show that a limited number of landslides in southern Palu Bay are sufficient to explain the tsunami data. The Palu tsunami highlights the difficulty in accurately capturing with tide gauges the amplitude and timing of short period waves that can have large impacts at the coast. The proximity of landslides to locations of high fault slip also suggests that tsunami hazard assessment in strike‐slip environments should include triggered landslides, especially for locations where the coastline morphology is strongly linked to fault geometry.