Abstract
The photo shows a weather station and a GPS station next to the Wankama temporary waterhole in Niger. The Trimble Zephyr GNSS antenna and the GPSMob tripod installed during the Gyraph project are visible. This project is dedicated to the study of the African monsoon by geodesy (gravimetry, GPS). These instruments belong to the National Mobile GNSS Park (GPSMob), which is part of Résif, a national research infrastructure dedicated to the observation and understanding of the internal Earth structure and dynamics. Résif is based on high-tech observation networks, composed of seismological, geodesic and gravimetric instruments deployed densely over the whole French territory. The data collected allow to study with a high spatio-temporal resolution the ground deformation, the superficial and deep structures, the seismicity at the local and global scale and the natural hazards, and more particularly the seismic ones, on the French territory. Résif is part of the European (EPOS - European Plate Observing System) and global systems of instruments allowing to image the interior of the Earth in its entirety and to study many natural phenomena.