Collaborative Research: Transport Dynamics and Mobility of Large-Scale Submarine Volcaniclastic Density Currents at Hunga Volcano, Tonga

In January 2022, the largest submarine explosive volcanic eruption recorded by modern instruments occurred at Hunga volcano in Tonga. This research will collect samples and new observations of volcanic sediment to understand how underwater volcanic eruptions transport material. The research uses this recent eruption to learn about underwater volcanic landslides that have been impossible to study directly until now. The results will help predict hazards from submarine eruptions. This project will include public outreach by a science communication professional. The project also involves international collaboration with the Kingdom of Tonga and the training of four graduate students. In 2022, Hunga Tonga volcano erupted explosively producing a widely studied stratospheric ash cloud and an estimated 10 cubic kilometers of much less well studied submarine volcaniclastic deposits. This project seeks to characterize the large-scale submarine volcaniclastic density currents produced by this eruption in order to better understand these understudied volcanic products globally. Systematic sampling and mapping in a field campaign using remotely operated submersible Jason, autonomous underwater vehicle Sentry, and ship-based gravity and slow coring will sample the eruption deposits at multiple spatial scales. These new data will enable computational modeling aimed at better understanding transport mechanisms, mobility, and rheology of submarine volcaniclastic flows. The 2022 Hunga Tonga eruption illustrated how vulnerable communication cables and other seafloor infrastructure are to these density currents. Similar volcanoes and similarly vulnerable infrastructure exist around the globe and particularly in the island arc systems around the Pacific. Broader impacts of this work will include four U.S. graduate students, involve public outreach from the ship and subsequent events hosted at the Smithsonian Institution. Extensive international collaboration is planned, with scientists, students, and a science communicator from Tonga included in the fieldwork and lab analysis. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.