MUG-OBS a geophysical multi-parameters ocean bottom station; a new versatile approach for monitoring earthquakes.

Yann Hello*1, Philippe Charvis1, Manuk Yegikyan2, Olivier Philippe2, Diane Rivet1, Anne Deschamps1

 1Laboratoire Geoazur Sophia Antipolis, France(, 2Osean SAS, Le Pradet, France

Real time acquisition data for oceanographer is the next great challenge for the future. There are several attempts to monitor real time seismic activity, using regional scale wired nodes, such as Neptune, Antares or DONET. These initiatives are costly to install and to maintain. Among the most recent alternative we developed a 4-years autonomy OBS equipped with a Trillium 120 s, a triaxial accelerometer, a differential and an absolute pressure gauge, and a hydrophone. MUG-OBS is a free-falling instrument rated down to 6000 m. The installation of the sensor and data quality are monitored by acoustic commands from the surface.

MUG-OBS is an improved system derivate from Broad Band OBS like Manta-OBS that meet two requirements: an easy access to the data collected by the instruments together with long-term deployments – up to 4 consecutive years. The major innovation is that it is possible to recover the data any time on demand using one of the 6 data-shuttles released from the surface by acoustic command. Last MUG-OBS version is also equipped with an acoustic modem to transmit selected data to an AUV.

Networks of synchronized autonomous hydrophones for monitoring the low-level seismic activity of the ocean floor and low-frequency sounds from the ocean has been commonly deployed in the world ocean to monitor large sections of mid-oceanic ridges.  HydrOBS is using the same technology developed for MUG-OBS and is equipped with 4 hydrophones. Data are recovered every year over a period of three years releasing 3 shuttles by acoustic.