On November 15, 2024, teams from the Géoazur research lab, the manufacturing company OSEAN and the crew of the French research vessel Téthys II, have successfully deployed the MUltiparameter Geophysical Ocean Bottom System (MUG-OBS) in the Ligurian Sea.

Settled at 2336 m depth in the EMSO Ligurian Sea Regional Facility (DYFAMED site), the MUG-OBS will record continuous time series for 4 years. Data shuttles, consisting of glass spheres that can be released from the sea surface by acoustic remote control, enable data to be retrieved every 6 months, without waiting for the station to come back up.

The MUG-OBS is an underwater seismological station equipped with a broadband seismometer, an accelerometer, absolute and differential pressure sensors, a hydrophone and a CTD for physical oceanography. The electronics have been updated in 2023 to replace components obsolete since the first deployment in 2016. This upgrade, funded by French government grants, also increased the previous 3.5-year autonomy by 6 months.

MUG-OBS was developed by Géoazur and OSEAN as part of the regional Ligurian CPER PRIMA-OCEANOMED project. It is maintained by the European Multidisciplinary Seafloor and water column Observatory – European Research Infrastructure Consortium (EMSO ERIC), as one of three stations in the EMSO-Ligurian network. The seismological and hydroacoustic time series data are archived in – and freely accessible from – the data center of Epos-France under the station name MUG01.FR.

Photo: The MUG-OBS onboard RV Téthys II moments before its redeployment in the Mediterranean Sea, 65 km offshore Nice on EMSO’s DYFAMED site. The mini-observatory was lifted off the rear deck and lowered to water level by the ship’s A-frame. After release from its ropes, the instrument sank to the seafloor at 2336 m depth. Credits: Aude Lavayssière, Géoazur.

Authors: Aude LAVAYSSIÈRE, Sébastien BONNIEUX, Karin SIGLOCH, Yann HELLO. Géoazur (Université Côte d’Azur, Observatoire Côte d’Azur, CNRS, IRD, Géoazur, CS 10269 – F 06905 Sophia Antipolis, France)

Campagne MUG-OBS: http://dx.doi.org/10.17600/18002900.