On the evening of December 22, 2018, the coasts of the Sunda Strait, Indonesia, were hit by a tsunami generated by the collapse of a part of the Anak Krakatau volcano. Hundreds of people were killed, thousands were injured and displaced. This paper presents a preliminary modeling of the volcano flank collapse and the tsunami generated based on the results of a 2D depth-averaged coupled model involving a granular rheology and a Coulomb friction for the slide description and dispersive effects for the water flow part. With a reconstructed total volume (subaerial and submarine) of the landslide of 150 million $$\hbox {m}^{3}$$ m 3 inferred from pre and post-collapse satellite and aerial images, the comparison of the simulated water waves with the observations (tide gauges located all around the strait, photographs and field surveys) is satisfactory. Due to the lack of information for the submarine part of the landslide, the reconstructed submarine slope is assumed to be approximately constant. A significant time delay on the results and particularly in the Bandar Lampung Bay could be attributed to imprecisions of bathymetric data. The sensitivity to the basal friction and to dispersive effects is analyzed through numerical tests. Results show that the influence of the basal friction angle on the simulated wave heights decreases with distance and that a value of $$2^{\circ }$$ 2 ∘ gives consistent results with the observations. The dispersive effects are assessed by comparing water waves simulated by a shallow water model and a Boussinesq model. Simulations with frequency dispersion produce longer wave periods and smaller wave amplitudes in the Sunda Strait and particularly in deep waters.

中文翻译：

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2018 年 12 月 22 日印度尼西亚喀拉喀托的山体滑坡和海啸：初步建模结果

2018 年 12 月 22 日晚，印度尼西亚巽他海峡沿岸发生了由喀拉喀托火山的一部分坍塌引发的海啸。数百人丧生，数千人受伤和流离失所。本文基于包含颗粒流变学和库仑摩擦的二维深度平均耦合模型的结果，对火山侧翼坍塌和产生的海啸进行了初步建模，该模型涉及滑动描述和水流部分的分散效应。从坍塌前后的卫星和航空图像推断出的滑坡总体积（地面和海底）重建为 1.5 亿美元$\hbox {m}^{3}$$ m 3，模拟水波的比较与观测（位于海峡周围的潮汐计、照片和实地调查）是令人满意的。由于缺乏滑坡海底部分的信息，重建的海底坡度被假定为近似恒定。结果的显着时间延迟，特别是在班达楠榜湾，可归因于测深数据的不精确。通过数值试验分析了对基础摩擦和分散效应的敏感性。结果表明，基底摩擦角对模拟波高的影响随着距离的增加而减小，$$2^{\circ }$$ 2 ∘ 的值与观测结果一致。通过比较浅水模型和 Boussinesq 模型模拟的水波来评估色散效应。频率色散模拟在巽他海峡，特别是在深水中产生更长的波周期和更小的波幅。