The objective of the series is to maintain a multi-sensor observation platform off Nice. The project named MUG-OBS, for Multiparameter Geophysical Ocean Bottom System, is a multi-sensor measurement system, autonomous, dropped from the surface and landed on the sea floor. It can be used at great depths and is capable of making continuous measurements and sending them to the surface periodically using air-droppable shuttles without having to bring up the underwater measurement station. MUG-OBS is part of an observation system under the aegis of the infrastructure EMSO-France, which completes the seismological network RESIF installed on land and whose data participate in the localization of earthquakes in the region, especially those taking place in the Ligurian Sea. In this IR, other seismometers are installed in the Ligurian region. The observation site EMSO-Ligure West (Toulon/Antares) is composed of a tri-axial seismometer, a tri-axial accelerometer and differential and absolute pressure sensors that will contribute to the confirmation of a potential tsunami warning. The EMSO Ligure-Nice site instruments the Nice airport platform (CNRS/IFREMER) with a seismometer of the same type that completes the other installed sensors (piezometers). The seismometers EMSO Ligure West and EMSO-Nice allow real time acquisitions. The MUG-OBS platform deployed on the EMSO-Dyfamed site off Nice, completes the marine coverage on the other side of the Var canyon and participates in the study of the physical parameters of the water column. MUG-OBS data are retrieved every six months by shuttles, thus ensuring a coherent observation system. These three devices meet the needs of observation and location at sea on the Mediterranean coast sensitive to earthquakes that complement land-based observations. The RAP seismological stations installed on the CADAM site serve as reference stations for the comparison of the seismic signature of regional events.