On December 22, 2018, a destructive tsunami related to the phenomena caused by the volcanic eruption of Gunung Anak Krakatau (GAK) was generated following a partial collapse of the volcano that caused serious damage and killed more than 400 people. This recent event challenged the traditional understanding of tsunami hazard, warning and response mechanisms and raised the topic of volcanic tsunami hazard. The complex mechanism of this tsunamigenic volcano collapse still needs further investigation as Anak Krakatau is one of the potentially tsunamigenic volcanoes in the world. This study investigates the possible source mechanisms of this phenomenon and their contribution to explaining the observed sea level disturbances by considering the impacts of this destructive event. We configured a flank collapse scenario with a volume of 0.25 km 3 as a combination of submarine and subaerial mass movement as the possible source scenarios to the December 22, 2018 Sunda Strait tsunami. A two-layer model is applied to simulate the tsunami generation by these landslides up to 420 s. The tsunami propagation and inundation are then simulated by NAMI DANCE model in GPU environment. The simulation results suggest that this scenario seems capable of generating such a tsunami observed along the coast of Sunda Strait. However, the contribution of the possible submarine mass movements in the close area between GAK and the surrounding islands either to this event or potential tsunami threat in the region is still questionable. We employed a bathymetric dataset through pre- and post-event analyses, which demonstrate submarine slope failures in the southwestern proximity of GAK. Hence, additional two scenarios of elliptical landslide sources on the slopes of bathymetry change area (could be triggered by seismic motion/volcanic eruption) are considered, searching for the possible effects of the tsunami that might be generated by these submarine landslides. The study may also provide some perspective for potential tsunami generation by combined sources and help to elucidate the extent of volcanic tsunami hazard in the region due to potential future eruptions of Gunung Anak Krakatau.

中文翻译：

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2018 年 12 月 22 日 Anak Krakatau 海啸的数值模拟和可能的海底滑坡情景检验

2018 年 12 月 22 日，喀拉喀托 (GAK) 火山局部坍塌，造成严重破坏并造成 400 多人死亡，引发了与火山喷发现象相关的破坏性海啸。最近的这一事件挑战了对海啸危害、预警和响应机制的传统认识，并提出了火山海啸危害的话题。由于喀拉喀托火山是世界上潜在的海啸火山之一，此次海啸火山坍塌的复杂机制仍有待进一步研究。本研究通过考虑这一破坏性事件的影响，调查了这种现象的可能来源机制及其对解释观测到的海平面扰动的贡献。我们配置了一个体积为 0 的侧面塌陷场景。25 km 3 作为潜艇和地面质量运动的组合作为 2018 年 12 月 22 日巽他海峡海啸的可能来源情景。应用两层模型来模拟这些滑坡长达 420 秒的海啸产生。然后在GPU环境中通过NAMI DANCE模型模拟海啸传播和淹没。模拟结果表明，这种情况似乎能够产生在巽他海峡沿岸观察到的这种海啸。然而，在 GAK 与周围岛屿之间的近距离区域内可能发生的潜艇大规模运动对该事件或该地区潜在的海啸威胁的贡献仍然值得怀疑。我们通过事前和事后分析采用了测深数据集，该数据集展示了 GAK 西南部附近的海底斜坡失效。因此，还考虑了测深变化区斜坡上的椭圆滑坡源的另外两种情景（可能由地震运动/火山爆发引发），以寻找这些海底滑坡可能产生的海啸的可能影响。该研究还可能为综合来源潜在的海啸产生提供一些视角，并有助于阐明由于 Gunung Anak Krakatau 未来可能爆发的火山海啸危害程度。