On December 22, 2018, a sector of the Anak Krakatau volcano edifice collapsed into the sea, generating a tsunami that hit the Sunda Strait coasts in Indonesia. The collapse followed a period of 6 months of volcanic activity that was insufficient to warn the tsunami-threatened coastal population. The Anak Krakatau tsunami resulted in hundreds of casualties, thousands of injured and displaced people, and massive coastal damage. This paper uses the tsunami records, the collected field survey data, and satellite imagery-based interpretations to develop a model of the Anak Krakatau flank failure and tsunami. We address the dynamics of the flank failure, the tsunami generation and propagation, and the coastal impact using evidence-calibrated numerical modelling. An in-house-developed multi-layer viscoplastic shallow-water numerical code is employed to simulate the Anak Krakatau collapse mass movement and the whole source-to-coast tsunami process. Our results suggest that a flank collapse scenario involving a volume of material of 0.135 km 3 and occurring as a sequence of two failures fairly reproduces the local and regional tsunami records and survey data.

中文翻译：

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2018 年 12 月 22 日的证据校准数值模型，Anak Krakatau 侧翼塌陷和海啸

2018 年 12 月 22 日，Anak Krakatau 火山大厦的一部分坍塌入海，引发海啸袭击印度尼西亚巽他海峡沿岸。坍塌是在 6 个月的火山活动之后发生的，但不足以警告受到海啸威胁的沿海人口。Anak Krakatau 海啸造成数百人伤亡、数千人受伤和流离失所，并造成大规模沿海破坏。本文使用海啸记录、收集的现场调查数据和基于卫星图像的解释来开发 Anak Krakatau 侧翼故障和海啸的模型。我们使用证据校准的数值模型来解决侧翼故障、海啸的产生和传播以及沿海影响的动力学问题。内部开发的多层粘塑性浅水数值代码用于模拟 Anak Krakatau 坍塌质量运动和整个源到海岸海啸过程。我们的结果表明，涉及 0.135 km 3 材料体积并作为两次故障的序列发生的侧翼坍塌情景相当再现了当地和区域海啸记录和调查数据。