Abstract
The image shows the experience of monitoring the GNSS deformation of the Pont du Gard during the passage of the Tour de France 2019. The GNSS system is a Trimble Geodetic 2 antenna. The objective is to measure the deformation modes of the Pont du Gard in order to estimate the strongest earthquake it has been able to resist during its millenary history. This instrument belongs to the mobile instrument park (GPSmob) of the French Seismological and Geodetic Network managed by the CNRS-INSU. Résif is a national research infrastructure dedicated to the observation and understanding of the structure and dynamics of the Inner Earth. Résif is based on high-tech observation networks, composed of seismological, geodetic and gravimetric instruments deployed in a dense manner throughout France. The data collected make it possible to study with high spatial and temporal resolution the deformation of the ground, surface and deep structures, seismicity on a local and global scale and natural hazards, and more particularly seismic events, on French territory. Résif is part of the European (EPOS - European Plate Observing System) and global systems of instruments used to image the Earth's interior as a whole and to study many natural phenomena.