Modelling of the tsunami from the December 22, 2018 lateral collapse of Anak Krakatau volcano in the Sunda Straits, Indonesia
Modelling of the tsunami from the December 22, 2018 lateral collapse of Anak Krakatau volcano in the Sunda Straits, Indonesia
复制标题
DOI：
10.1038/s41598-019-48327-6
复制
发表时间：
2019-08-16
影响因子：
4.6
通讯作者：
Muin, Muslim
中科院分区：
文献类型：
--
作者：
Grilli, Stephan T.;Tappin, David R.;Muin, Muslim
当地时间2018年12月22日20时55分左右，位于印度尼西亚Sunda海峡的Anak Krakatau火山在6月份开始的喷发活动期内发生重大侧向坍塌。坍塌将火山碎屑物质释放到火山西南250米深的火山口，在苏门答腊岛和爪哇邻近的海岸引发了高达13米的海啸。海啸造成至少437人死亡，是自1883年克拉卡托灾难性爆发和1888年里特岛扇区坍塌以来，火山引发的海啸造成的最大死亡人数。100多年来，2018年Anak Krakatau事件首次提供了一个机会来研究一场由火山引发的重大海啸，这场海啸造成了广泛的生命损失和重大破坏。在这里，我们介绍了海啸的数值模拟，使用最先进的数值模型，基于滑坡来源和水深测量的组合数据集。通过对地震前后卫星图像和航空摄影的分析，我们确定了滑坡源的几何形状和大小，这些分析表明，原始滑坡伤疤将Anak Krakatau火山一分为二，切割了中央喷口后面，并移走了50%的地面范围。估算的海底坍塌几何形状导致了0.22-0.30公里(3)的主要滑坡体积范围，该范围被用来初始化具有两种不同滑坡流变性(颗粒和流体)的海啸发生和传播模型。对没有后续海浪的单一海啸的观察，与我们对滑坡破坏的解释是一致的，这是一个快速、单一的运动阶段，而不是一个更零散的过程，产生的海啸在大约30分钟内到达附近的海岸线。这两种模拟的流变学都成功地从灾后现场调查结果、验潮仪记录和目击者报告中再现了观测到的海啸特征，表明我们估计的滑坡体积范围是合适的。这一事件突出了相对较小规模的横向火山崩塌造成的重大危险，这种崩塌可以集体发生，没有任何前兆信号，是一个有效和不可预测的海啸来源。我们的成功模拟表明，当前的数值模型可以准确地预测这些事件带来的海啸危险。在Anak Krakatau这样的情况下，没有前兆预警信号，加上海啸启动后旅行时间短，对减轻海啸对沿海的影响构成了重大挑战。
On Dec. 22, 2018, at approximately 20: 55-57 local time, Anak Krakatau volcano, located in the Sunda Straits of Indonesia, experienced a major lateral collapse during a period of eruptive activity that began in June. The collapse discharged volcaniclastic material into the 250 m deep caldera southwest of the volcano, which generated a tsunami with runups of up to 13 m on the adjacent coasts of Sumatra and Java. The tsunami caused at least 437 fatalities, the greatest number from a volcanically-induced tsunami since the catastrophic explosive eruption of Krakatau in 1883 and the sector collapse of Ritter Island in 1888. For the first time in over 100 years, the 2018 Anak Krakatau event provides an opportunity to study a major volcanically-generated tsunami that caused widespread loss of life and significant damage. Here, we present numerical simulations of the tsunami, with state-of the-art numerical models, based on a combined landslide-source and bathymetric dataset. We constrain the geometry and magnitude of the landslide source through analyses of pre-and post-event satellite images and aerial photography, which demonstrate that the primary landslide scar bisected the Anak Krakatau volcano, cutting behind the central vent and removing 50% of its subaerial extent. Estimated submarine collapse geometries result in a primary landslide volume range of 0.22-0.30 km(3), which is used to initialize a tsunami generation and propagation model with two different landslide rheologies (granular and fluid). Observations of a single tsunami, with no subsequent waves, are consistent with our interpretation of landslide failure in a rapid, single phase of movement rather than a more piecemeal process, generating a tsunami which reached nearby coastlines within similar to 30 minutes. Both modelled rheologies successfully reproduce observed tsunami characteristics from post-event field survey results, tide gauge records, and eyewitness reports, suggesting our estimated landslide volume range is appropriate. This event highlights the significant hazard posed by relatively small-scale lateral volcanic collapses, which can occur en-masse, without any precursory signals, and are an efficient and unpredictable tsunami source. Our successful simulations demonstrate that current numerical models can accurately forecast tsunami hazards from these events. In cases such as Anak Krakatau's, the absence of precursory warning signals together with the short travel time following tsunami initiation present a major challenge for mitigating tsunami coastal impact.