In response to the volcanic eruption of Mayotte that began in May 2018 and the associated seismicity, the French Government entrusted the monitoring mission of this volcanic area to the Mayotte Volcanological and Seismological Monitoring Network (REVOSIMA). The IPGP operates this network through the Volcanological Observatory of Piton de la Fournaise (OVPF-IPGP) in co-responsibility with the BRGM and its regional office in Mayotte. REVOSIMA is based on a close scientific and technical partnership with Ifremer and the CNRS.

Within the framework of REVOSIMA, Ifremer, BRGM, IPGP and CNRS acquire marine geophysical data allowing the production of bathymetric and reflectivity maps of the seabed, and the analysis of acoustic plumes caused by emissions of fluids or particles in the water column. They also maintain a network of underwater instruments, in particular seabed seismometers, which record the waves generated by earthquakes and allow their source to be located with precision.

The MAYOBS 18 monitoring campaign benefits from the presence of the oceanographic vessel the Pourquoi Pas? near Mayotte and close to GEOFLAMME scientific campaign. The pooling of human and technical resources makes it possible to increase the number of monitoring missions for relevant monitoring of the evolution of phenomena.

• Map the morphology of the seabed, detect plumes in the water column from fluid emissions (gas, liquid and particles) and possible lava emissions to assess the activity since the last campaign (MAYOBS17, January 2021 ) and activity in progress.
• Retrieve data and keep operational the following instrument networks:
  • Ocean Bottom Seismometers (OBS) to relocate precisely the seismicity recorded by land stations.
  • The hydrophones deployed during MAYOBS15 in October 2020 will provide their first data. This network aims to "listen" to the noises transmitted in the water column during the installation of the flows around the new volcano.
  • The pressure sensor deployed on the seabed in October 2020 during MAYOBS15 will also provide its first data. This sensor makes it possible to measure the vertical variations of the seabed at the level of the main seismic swarm.