Since their discovery in subduction zones in the early 2000s, slow earthquakes have been the subject of many studies to understand their mechanism and their role in the seismic cycle, particularly their influence on seismic hazard. Slow earthquakes emit only very weak signals that are measurable by seismology, but can, if large enough, cause surface displacements. Space geodesy provides tools like continuous GPS and satellite radar interferometry that are very complementary to seismological measurements in order to detect and study them. In the Mexican subduction zone along the Pacific coast, periodic (about every 4 years) large slow earthquakes are recorded among the largest in the world, in the Guerrero region and to a lesser extent and less regularity in the Oaxaca region.

We will present the potential of ESA satellites Sentinel-1a and 1b to explore the ground deformation of the entire subduction zone (covering a 1000 km x 400 km band) with good spatial resolution. These satellites are capable of radar interferometric measurements with better temporal resolution than previous generations. By allowing a more systematic measurement of deformations, these satellites should be able to capture the next major slow seismic event in the Guerrero area as well as possible new slow earthquakes in areas poorly covered by permanent and seismological GPS networks. They should also make it possible to better measure the coupling spatial and temporal variations in coupling on the subduction interface, which could indirectly reflect a slow slip activity.