Challenges of the GEOSCOPE Observatory.

The GEOSCOPE observatory consists of a global seismic network and a data center. The observatory was launched in 1982 by the French National Center of Scientific Research (CNRS/INSU) and progressively 30 stations have been installed across all continents and on islands throughout the oceans. The GEOSCOPE stations are located on 18 countries and equipped with three component very broad-band seismometers (STS1 or STS2) and 24 or 26 bit digitizers, as required by the Federation of Seismic Digital Network (FDSN). In most stations a pressure gauge and a thermometer are also installed. During the last years, 13 stations have been upgraded in order to send data in real or near real time to GEOSCOPE Data Center. In 2008, two new real time stations will be installed in the Indian Ocean: in the South of Madagascar and on Rodrigues island. Four stations in the Carribean region and in South America will also be upgraded to send real time data to GEOSCOPE Data Center and to local tsunami warning centers. Continuous data of all stations are collected in real time or with a delay by the GEOSCOPE Data Center in Paris where they are validated, stored and made accessible to the international scientific community. Users have free and open access to: - real time data from 13 stations. These data are transfered from the stations to the Geoscope Data Center using the seedlink protocol developed by GEOFON. Seedlink also enables to make these data accessible to the Tsunami Warning Centers and to other data center. These data are available to users through the GEOSCOPE web interface. - validated continous waveforms and meta data of all stations by using the NetDC system (Networked Data Centers). Data can be requested from the GEOSCOPE Data Center and from other networked centers associated to the FDSN. - a selection of seismograms corresponding to large earthquakes via a web interface - the power spectrum estimates of the seismic noise averaged over sequences of 24 hours for each station. The noise levels of the past 10 years of continuous data has been computed and are accessible via the web. The noise level of real time data is computed at day-8. GEOSCOPE data center is now networked to the French virtual data center, FOSFORE, in order to give a unique access to french seismological data. In Europe, GEOSCOPE data center participates in NERIES project (NA3 activity) in order to create a distributed archive and database for all continuous digital waveform recordings of the Euro-Mediterranean region.