The GEOSCOPE program: state of the art in 2005

The GEOSCOPE program was launched in 1982 by the National Institute of Sciences of Universe (INSU), a department of the French National Center of Scientific Research (CNRS), at the instigation of the Institute of Physics of the Earth of Paris (IPGP). The purpose was the installation of about 25 stations well distributed worldwide (in particular in the southern hemisphere), in the standard configuration defined by the FDSN (very broad-band 24 bit, continuous recording at 20sps). The GEOSCOPE program is operating 28 digital 3-component very- broadband stations. Data from large events are teletransmitted from some stations (by phone RTC line or through internet) and made available within one day. A satellite transmission system is now working, in cooperation with the french military agency CEA/DASE, in cooperation with CTBTO (Dzumac in New Caledonia), and the data are available continuously, with a low gain. We are replacing the old Streckeisen digitizers with new Quanterra type ones, in order to be ready for the next step which will consist in gathering data towards our Data Center in real-time. Presently data from 6 stations arrive at the IPGP Geoscope Data Center in near real-time, with a delay depending on the station. The challenge is to link the maximum number of stations to our Data Center for getting data in real time; that purpose can be reached in few years. We are able to upgrade 3 or 4 stations every year, giving priority to the ones easy to link permanently to Paris. For the last ten years we've been progressively installing microbarometers and thermometers, transforming all our stations in multiparameter observatories. In terms of siting locations, the aim of the GEOSCOPE program is almost fulfilled; we re-installed the chinese station WUS with modern equipment in October 2004, we installed in December 2004 a new station TAOE in Marquesas Islands in cooperation with CEA/DASE, another one COYC in Patagonia (Chile) in December 2004. We plan to install a second station in Russia at high latitude at VOR (Vorkuta). In the framework of cooperation between IRIS and GEOSCOPE we installed in March 2004 a joint station at TRIS (Tristan Da Cunha), and we decided to share our equipment at KIP station that became a joint station. Our purpose is to maintain our stations at original sites (high latitudes) and to fill some geographical gaps in the southern hemisphere.