New High-Resolution Modeling of the 2018 Palu Tsunami, Based on Supershear Earthquake Mechanisms and Mapped Coastal Landslides, Supports a Dual Source
New High-Resolution Modeling of the 2018 Palu Tsunami, Based on Supershear Earthquake Mechanisms and Mapped Coastal Landslides, Supports a Dual Source
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DOI：
10.3389/feart.2020.598839
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发表时间：
2021-01
期刊：
影响因子：
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通讯作者：
L. Schambach;S. Grilli;D. Tappin
中科院分区：
文献类型：
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作者：
L. Schambach;S. Grilli;D. Tappin
2018年9月28日，印度尼西亚中苏拉威西岛发生了里氏7.5级地震，随后帕卢湾发生了沿海山体滑坡和破坏性海啸。在这里，我们提出了新的海啸模型，支持双源机制，从超剪切走滑地震和沿海滑坡。到目前为止，海啸的机制：地震，沿海滑坡，或两者的组合，仍然存在争议，因为发表的研究一直没有定论;一些研究解释了地震和其他滑坡的大多数观测结果。主要的挑战是海啸建模中使用的许多不同的震源模型，以及滑坡机制一直是假设的。在这里，我们模拟海啸生成使用三个已公布的地震模型，单独和结合7个沿海滑坡在早期的工作中确定，并确认了现场和测深证据，从视频证据，产生了显着的波。为了产生和传播的海啸，我们使用两个波模型，三维非流体静力学模型NHWAVE和二维Boussinesq模型FUNWAVE-TVD的组合。这两个模型都是非线性的，并解决了在模拟海啸从滑坡，在这里，在NHWAVE被建模为粒状材料的波频散的物理关键。我们的组合，地震和沿海滑坡，模拟重建所有观察到的海啸助跑，除了那些在帕卢湾东南部，他们是最高的（10.5米），以及在视频记录和位于帕卢湾内的潘托洛安港验潮仪的观测。关于海啸对海岸影响的时间，从滑坡/地震双重源，特别是那些使用超剪切地震模型的结果与重建的时间序列在大多数地方是很好的协议。我们的新工作表明，一个额外的海啸机制也是必要的，以解释在帕卢湾东南部的海啸观测升高。使用部分信息，在这方面的测深调查，我们表明，一个额外的，海底滑坡在这里，当模拟与其他沿海幻灯片，和超剪切地震机制更好地解释了观测。这支持了今后在这一领域开展海洋地质工作的必要性。
The Mw 7.5 earthquake that struck Central Sulawesi, Indonesia, on September 28, 2018, was rapidly followed by coastal landslides and destructive tsunami waves within Palu Bay. Here, we present new tsunami modeling that supports a dual source mechanism from the supershear strike-slip earthquake and coastal landslides. Up until now the tsunami mechanism: earthquake, coastal landslides, or a combination of both, has remained controversial, because published research has been inconclusive; with some studies explaining most observations from the earthquake and others the landslides. Major challenges are the numerous different earthquake source models used in tsunami modeling, and that landslide mechanisms have been hypothetical. Here, we simulate tsunami generation using three published earthquake models, alone and in combination with seven coastal landslides identified in earlier work and confirmed by field and bathymetric evidence which, from video evidence, produced significant waves. To generate and propagate the tsunamis, we use a combination of two wave models, the 3D non-hydrostatic model NHWAVE and the 2D Boussinesq model FUNWAVE-TVD. Both models are nonlinear and address the physics of wave frequency dispersion critical in modeling tsunamis from landslides, which here, in NHWAVE are modeled as granular material. Our combined, earthquake and coastal landslide, simulations recreate all observed tsunami runups, except those in the southeast of Palu Bay where they were most elevated (10.5 m), as well as observations made in video recordings and at the Pantoloan Port tide gauge located within Palu Bay. With regard to the timing of tsunami impact on the coast, results from the dual landslide/earthquake sources, particularly those using the supershear earthquake models are in good agreement with reconstructed time series at most locations. Our new work shows that an additional tsunami mechanism is also necessary to explain the elevated tsunami observations in the southeast of Palu Bay. Using partial information from bathymetric surveys in this area we show that an additional, submarine landslide here, when simulated with the other coastal slides, and the supershear earthquake mechanism better explains the observations. This supports the need for future marine geology work in this area.