Hydroacoustic monitoring of Mayotte underwater volcanic eruption

Mooring networks of hydrophones is an effective way to monitor the ocean soundscape and its sources, and it is particularly efficient to better understand underwater volcanic eruptions. In October 2020, four continuous hydrophones were moored in the SOFAR channel around Mayotte Island, in the North Mozambique Channel, to monitor the Fani Maoré 2018-2022 submarine eruption. This eruption created a new underwater seamount at 3500 m below sea level, 50 km east of Mayotte. Since 2020, the MAHY hydrophones record sounds generated by the volcanic activity and the first results have evidenced earthquakes, underwater landslides, and impulsive signals that we related to steam bursts during lava flow emplacement. An automatic detection of these specific impulsive signals is being developed for a better monitoring but also a better understanding of their source. The hydroacoustic catalog obtained characterize the Mayotte lava flow activity and will help quantify the risk for Mayotte population. This detection could be used by Mayotte’s and other volcano observatories to monitor active submarine eruptions in the absence of regular seafloor imaging.