Installation location: Environmental platform
Discipline: Internal geophysics
Research area: Seismotectonics
Context
The permanent GPS network aims to continuously measure signals from GNSS satellites (GPS, GLONASS, GALILEO) to measure horizontal and vertical surface deformations of the continental crust, the primary purpose of RENAG. The network is deployed across the entire national territory with a higher density in the most tectonically active areas: the Alps, the Pyrenees and the Rhine divide. The data is also integrated by Météo France to estimate atmospheric water vapor in its forecast models. RENAG is currently responsible for the Grenoble Observatory (OSUG).
Method and Operation of the installation
The station is autonomous. The data is recorded at two frequencies: at 30 seconds for geophysical applications and at 1 second for weather and geophysical applications in the event of major events such as an earthquake or a landslide very close to the station. The station automatically sends the data to the archiving and processing centers: the Permanent GPS Network (RGP) of the IGN and the RENAG at Géoscience Azur in Nice. These centers calculate a daily position of each station and thus constitute time series.
The data, once validated, are made available to the public.
Expected results
Since crustal deformations are very low in France, only the establishment of time series covering at least 3-5 years makes it possible to get out of the measurement noise and determine horizontal and vertical velocities of tectonic deformation (tectonic plates, faults, certain crustal instabilities, global deformation of a mountain range, etc.) with submillimeter precision.
The data is also used to improve weather forecasting models by Météo France. The data is also used by expert surveyors.
Laboratories and Partners involved
The network covers the national territory in a collaboration including the CNRS/INSU, the IGN, the CNES, the EXAGONE expert surveyor network and the private ORPHEON network.