Collaborative Research: Physical Modeling of Submarine Volcanic Eruption Generated Tsunamis

海啸通常与俯冲带的海底地震有关，比如2011年的日本海啸。然而，有重要的海啸源与海底火山爆发有关。火山海啸，像构造海啸一样，通常在没有预警的情况下发生，可以摧毁离火山相当远的人口稠密的沿海地区。在过去的250年里，有超过90次火山海啸，造成的死亡人数约占由火山爆发直接导致的死亡人数的25%。在过去300年里，最致命的两次非构造海啸分别是1883年印尼喀拉喀托火山爆发引发的火山碎屑流和1792年日本云仙火山熔岩穹丘坍塌。在震源处，火山海啸的波高可以超过构造海啸，但随着传播距离的增加，火山海啸的波有明显的衰减和频散。火山产生海啸至少有九种不同的机制。大多数火山海啸波是由海底或靠近水面的火山爆发产生的，或者是由大量火山碎屑流或碎片雪崩流入海洋造成的。2015年7月，加勒比海格拉纳达（Granada）附近的Kick 'em Jenny海底火山发出了最近的“橙色”警报，突显了为潜在的海底火山喷发描绘海啸波的挑战。在这项工作中，我们将进行一系列实验和密切相关的建模工作，以量化源喷发机制与波浪产生之间的关系。这项研究将有助于评估和减轻火山和海啸双重灾害。本研究的最终长期目标是通过海底火山喷发、海啸产生和传播以及潜在的吞没和破火山口形成的混合模型来转变海底火山海啸危害的评估和缓解。文献中缺乏与这些海底海啸产生过程有关的至关重要的数据。本研究将通过海底火山喷发海啸生成场景的三维混合建模来弥补数据的缺失。它将重点关注海底火山爆发和吞没所产生的海啸。计算机控制的气动海底火山爆发海啸发生器（SVE-TG）将允许完全的三维物理建模。SVE-TG的不同喷发速度模拟了相对缓慢的泥火山和快速的爆发。事件分析将用于确定SVE-TG的实验方案和设计，这将扩大现有NHERI海啸设施的能力。实验程序将确定动态喷发柱和耦合海啸的产生、传播和潜在的火山口形成的特征。海底火山喷发的联合实验结果将为海底火山喷发和吞没的数值模型提供可靠的验证工具。从目前的实验和数值研究来看，海底火山喷发事件的源特征仍然很差。用描述的耦合火山团流、喷发和海啸机制来模拟一个历史事件。这项研究将改变对海底火山海啸的认识和理解，并可能减轻一些最致命的非构造海啸危害。

Tsunamis are normally associated with submarine earthquakes along subduction zones, such as the 2011 Japan tsunami. However, there are significant tsunami sources related to submarine volcanic eruptions. Volcanic tsunamis, like tectonic tsunamis, typically occur with little warning and can devastate populated coastal areas at considerable distances from the volcano. There have been more than 90 volcanic tsunamis accounting for about 25% of all fatalities directly attributable to volcanic eruptions during the last 250 years. The two deadliest non-tectonic tsunamis in the past 300 years are due to the 1883 Krakatoa eruption in Indonesia with associated pyroclastic flows and Japan's Mount Unzen lava dome collapse in 1792. At the source, volcanic tsunamis can exceed tectonic tsunamis in wave height, but these volcanic tsunamis are subject to significant wave attenuation and dispersion with propagation distance. There are at least nine different mechanisms by which volcanoes produce tsunamis. Most volcanic tsunami waves have been produced by extremely energetic explosive volcanic eruptions in submarine or near water surface settings, or by flow of voluminous pyroclastic flows or debris avalanches into the sea. The recent "orange" alert in July 2015 at the Kick 'em Jenny submarine volcano off Granada in the Caribbean Sea highlighted the challenges in characterizing the tsunami waves for a potential submarine volcanic eruption. In this work we will conduct a suite of experiments and closely linked modeling efforts to quantify the relationship between source eruptive mechanism and wave generation. This research will serve assessment and mitigation of coupled volcanic and tsunami hazards.The ultimate long-term goal of this research is to transform assessment and mitigation of the submarine volcanic tsunami hazard through hybrid modeling of submarine volcanic eruption, tsunami generation and propagation along with the potential engulfment and caldera formation. Critically important data related to these submarine tsunami generation processes is lacking in the literature. This research will compensate for missing data by hybrid modeling of 3D submarine volcanic eruption tsunami generation scenarios. It will focus on the tsunami generation by submarine volcanic eruptions and engulfments. A computer controlled pneumatic submarine volcanic eruption tsunami generator (SVE-TG) will allow fully 3D physical modeling. The variable eruption velocities of the SVE-TG mimick relatively slow mud volcanoes and rapid explosive eruptions. The event analysis will be used to determine the experimental program and the design of the SVE-TG, which will expand the capabilities of the existing NHERI tsunami facilities. The experimental program will determine the characteristics of the dynamic eruptive column and the coupled tsunami generation, propagation and potential caldera formation. The combined experimental results from the submarine volcanic eruption will provide a robust validation tool for numerical models of submarine volcanic eruptions and engulfments. Source characteristics from submarine volcanic eruption events remain poorly constrained from present experimental and numerical studies. A historical event will be simulated by using described coupled volcanic mass flow, eruption and tsunami mechanisms. This research will transform knowledge and understanding of submarine volcanic tsunamis and potentially mitigate some of the deadliest non-tectonic tsunami hazards.