GEOSTAR, a deep sea observatory 

First long duration mission (September 2000 /April 2001) at 1900 meter depth, off-shore Ustica Island (Sicily)

GEOSTAR (Geophysical and Oceanographic Station for Abyssal Research) is a project developed within the frame of MAST-3 European program. The aim of the project is to develop and then test at sea in real conditions a permanent and autonomous observatory, able to record and transmit various measurements relating to seismology, geophysics and oceanography.

Co-ordinated by the National Italian Institute of Geophysics and Volcanology (INGV), GEOSTAR does work together 8 partners from Italy, Germany and France.

The project first phase was completed at the end of 1998 with the deployment of a prototype at small water depth (40 m) during two weeks offshore Ravenna (Adriatic Sea).

During the second phase of the project, the system capacities have been increased in order to be able to perform long duration measurement campaigns from six months to one year and up to 
 4000 m depth.

A near real time communication system has been developed through which it is possible to send commands to the station and recover daily reports of the system operations.

The first mission of the GEOSTAR-2 system was the seven month measurement campaign performed from September 2000 to April 2001 offshore Ustica Island (Sicily) at 1900 m depth.

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 the bottom station and mobile docker
 

GEOSTAR system is composed of 4 main sub-systems:

  • the scientific instrumentation : differing from one mission to another: seismometer, magnetometer, gravimeter, geochemical probes, CTD, acoustic doppler current meter …
  • the bottom station itself : that is an aluminium structure which supports the scientific instruments and the pressure resistant vessels containing either the electronic units for system management and data storing or the battery energy source.
  • the mobile docker : which is the tele-operated handling system used to deploy the station on sea bottom and recover it.
  • the communication systems : the first one consisting  of in a set of releasable buoyant data capsules named "messengers" and the other one composed of an acoustic and a satellite transmission link in series.

These communication systems have been developed jointly by Ifremer and  company ORCA instrumentation.