Title: Imaging the magmatic systems under submarine volcanoes with satellite altimetry

Abstract:

The magmatic systems under most submarine volcanoes are poorly known and have not been imaged by geophysical techniques, due to their inaccessibility and the time and cost needed for research cruises. In this talk, I investigate the detectability of magma reservoirs in the vertical gravity gradient (VGG) anomalies calculated from satellite altimetry data. We will first look at a suite of synthetic seamount models to identify the expected gravity signature of magmatic systems. One of the largest explosive eruptions instrumentally recorded occurred at Hunga volcano (Tonga) on 15 January 2022. I will show how we can use marine gravity data derived from satellite altimetry combined with multibeam bathymetry to model the architecture and dynamics of the magmatic system before and after the January 2022 Hunga eruption. Finally, we will see how global satellite altimetry data with increasing resolution offer a promising reconnaissance tool to probe the subsurface for magma at other submarine volcanoes, including those in the Izu-Bonin-Mariana arc.