Volcanic Debris Avalanches - From Collapse to Hazard
Volcanic Debris Avalanches - From Collapse to Hazard
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火山碎片雪崩 - 从崩塌到危险
DOI：
10.1007/978-3-030-57411-6_10
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Watt S
中科院分区：
文献类型：
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作者：
Watt S
许多火山岛近海的滑坡沉积物提供了灾难性侧向塌陷的证据。这些沉积物的体积范围比大陆上的沉积物更大，可以产生毁灭性的海啸。所有历史上的火山岛侧向崩塌都发生在弧形环境中，其特征是快速失效和有效的海啸生成。其沉积物的不同形态受岩性和基底性质的影响。许多沉积物显示出海底受到广泛侵蚀并转变为泥石流的证据，以及前限沉积物变形在原始存款之外和之下的传播。可动体积可能远远超过最初的故障，准确的存款解释需要内部地球物理成像和采样。围绕板内洋岛火山，多单元浊积岩表明，横向崩溃可能会发生在离散的阶段，虽然这将降低其整体海啸的潜力，崩溃的各个阶段的体积仍然非常大。滑坡和海啸过程中的海洋岛屿设置的数值模型是很难测试，和较小的崩溃，典型的岛弧是一个重要的研究重点，由于其较高的全球频率，直接故障和海啸观测的可用性，并需要更好地了解早期崩溃的信号，以制定减轻海啸灾害的方法。
Landslide deposits offshore many volcanic islands provide evidence of catastrophic lateral collapses. These deposits span a larger volume range than their continental equivalents, and can generate devastating tsunamis. All historical volcanic-island lateral collapses have occurred in arc settings, and have been characterised by rapid failure and efficient tsunami generation. The varied morphology of their deposits is influenced both by lithological properties and the nature of the substrate. Many deposits show evidence of extensive seafloor erosion and transformation into debris flows, and the propagation of frontally-confined sediment deformation beyond and beneath the primary deposit. Mobilised volumes can far exceed that of the initial failure, and accurate deposit interpretation requires internal geophysical imaging and sampling. Around intraplate ocean-island volcanoes, multi-unit turbidites suggest that lateral collapses may occur in discrete stages; although this would reduce their overall tsunamigenic potential, the volumes of individual stages of collapse remain very large. Numerical models of both landslide and tsunami processes in ocean-island settings are difficult to test, and the smaller collapses that typify island arcs are an important focus of research due to their higher global frequency, availability of direct failure and tsunami observations, and a need to better understand the signals of incipient collapse to develop approaches for tsunami hazard mitigation.