As part of the actions carried out by the public authorities, to better understand the seismic-volcanic phenomenon that has affected Mayotte since May 2018, a new cruise is being organized off the island from July 9 to 23, 2022 by the REVOSIMA onboard the Marion Dufresne.

The MAYOBS23 cruise aims to establish new underwater maps to monitor seismic-volcanic activity on the seabed and to maintain in working order the measuring stations on the seabed and in the water column in order to follow the evolution of the seismo-eruptive activity, of the submarine morphologies and of the fluids emissions, since the last MAYOBS21 monitoring cruises (September 2021) and to acquire geological data useful for the understanding of the current phenomenon.

MAYOBS23 includes a section dedicated to the maintenance and recovery of data from six Ocean Bottom Seismometers (OBS), two A-0-A pressure sensors and four hydrophones. MAYOBS23 will make it possible to carry out acoustic surveys from the ship and from an autonomous underwater vehicle (AUV), as well a towed camera (SCAMPI). The parameters monitored include the evolution of the underwater relief, physical or chemical anomalies linked to fluid emissions in the water column. MAYOBS23 also aims to collect rock samples by dredging the seabed, but also the water column by CTD-Rosette. Laboratory analysis of these samples will identify any traces of current or past eruptions.