DOI: 10.17603/ds2-q9dq-as89
title: Physical modeling of tsunamis generated by submarine volcanic eruptions
title: in NHERI Volcanoes - Physical modeling of submarine volcanic eruption generated tsunamis

description: The volcanic tsunami generator (VTG) experiments were performed in the Directional Wave Basin at the O. H. Hinsdale Wave Research Laboratory at Oregon State University in Corvallis, Oregon. The experiment primarily designed for studying tsunami waves generated by underwater volcanic eruption. The designed wave maker is a novel pneumatic volcanic tsunami generator to generate volcanic tsunamis with repeatable and controlled source parameters. Synchronized measurements of the cylindrical wave profile are obtained from the wave gauge array and cameras deployed in the basin. Empirical equations are derived to characterize and evaluate tsunami wave parameters, which can help improve current tsunami warning and mitigation systems with consideration of volcanic tsunami hazards.
description: 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.