Collaborative Research: Multi-scale Geodetic Monitoring at Axial Seamount

This project continues long-term research and monitoring of the most active submarine volcano in the NE Pacific named Axial Seamount. It is located about 300 miles off the coast of Oregon and represents an excellent site to study how volcanoes work because it erupts frequently, has numerous monitoring instruments, and has repetitive behavior. This research will improve understanding of how magma (molten rock) is stored in the shallow crust at volcanoes, how it is delivered to the surface, how eruptions are triggered, and how eruptions can be successfully forecast. Scientists will use pressure sensors and underwater vehicles to measure movements of the seafloor at Axial Seamount. These movements take place as the volcano gradually inflates with magma between eruptions, like a balloon, and then rapidly deflates during eruptions. The seafloor moves up and down as much as 8-12 feet during these cycles. When the volcano is fully inflated it is ready to erupt again. Scientists have observed that Axial Seamount inflates to a similar level before each eruption, which has enabled two previous eruptions to be successfully forecast months in advance. Therefore, this research has broad implications for reducing hazards at volcanoes around the world. This work will improve eruption forecasting at all volcanoes, including those on land. Axial Seamount erupted in 1998, 2011, and most recently in April 2015 and is more than 90% re-inflated in 2022, so is building toward another eruption. It is an ideal natural laboratory for the long-term study of active processes at a submarine volcano in a mid-ocean ridge setting. Long-term research and monitoring at Axial have built a remarkable time-series of bottom pressure observations that have revealed a repeated cycle of inflation and deflation that has been used to forecast eruptions with increasing accuracy. The 2015 eruption was the first captured in real time by the Ocean Observatories Initiative (OOI) Regional Cabled Array (RCA) and the network of sensors revealed the inner workings of the volcano in unprecedented detail. Nevertheless, understanding is improved with every eruption and novel techniques are revealing new and surprising phenomena that were previously unknown. An example of this derives from the use of repeated high-resolution bathymetric mapping using Autonomous Underwater Vehicles (AUVs) that show that the deformation field extends over the entire summit caldera and beyond. The new AUV data are complementary to the pressure measurements in that the AUV surveys are spatially continuous and laterally extensive, whereas the pressure measurements are temporally continuous but are spatially limited. During this project, scientists will continue the pressure measurements and further develop the AUV repeat bathymetry technique using Terrain Relative Navigation (TRN) during fieldwork in 2024, 2026, and 2028. The two datasets will be a powerful combination for advancing deformation modeling of the subsurface magmatic system at Axial Seamount.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.