Abstract
Violent underwater explosive eruptions can suddenly displace large volumes of water, which have the potential to generate devastating tsunamis. Tsunamis triggered by underwater volcanic eruptions can cause destruction well beyond the range of the eruption itself, as recently demonstrated by the 2022 eruption of the Hunga Tonga-Hunga Ha’apai (HTHH) volcano. The challenges of applying existing predictive methods to the local and transoceanic tsunamis generated during this event highlight the importance of more research into tsunamis of volcanic origin.
Although a large quantity of field data was collected by many modern instruments around the world following the 2022 HTHH eruption, the inaccessibility of underwater environments and the lack of direct observations at/near submerged vents leaves the wave generation mechanisms still relatively poorly understood. In this study, we developed complementary datasets through novel laboratory experiments, where either compressed air or steam was injected into a tank with a range of water depths, applied pressures, jet durations, and tank water temperatures. To investigate the influence of these variables on the jet-plume morphologies, free surface disturbances, and wave properties, we simultaneously recorded the evolution of the eruption and related waves in each experiment. The experimental results suggest that, for a given eruption, there is a critical water depth associated with the most effective wave generation and a containment water depth associated with negligible wave generation. The experiments also show a saturation duration above which the maximum wave height does not increase with increasing jet duration. This study provides insights into the fundamental wave generation mechanisms related to underwater volcanic eruptions and will improve the interpretation and predictive capability of this natural disaster.