Description
Between November 2019 and November 2022, a series of seismic events were felt by the population of the city of Strasbourg, France. The first main event (MLv 3.0) that occurred on November 12, 2019, was part of a seismic swarm (the southern cluster) that has been initiated a few days before, lasted four months, and was located by the BCSF-Rénass (EOST), below La Robertsau area at a depth of 5 km. In October 2020, after a new series of hydraulic tests, second cluster of seismic events with more felt earthquakes (the northern cluster) developed closer to the geothermal wells (<1 km) below the La Wantzenau area. It includes the largest event (MLv 3.9) that was induced on June 26, 2021, 6 months after the shut-in of the wells. Two important features of the induced seismicity were unexpected : the large distance to the wells of a cluster of seismic events (4-5km) and the occurrence of the largest event Mlv3.9 at the bottom of the wells, six months after shut-in. To better understand the mechanisms of seismicity, we develop within the framework of the DT-GEO project, a large-scale model (8kmx8kmx6km) of the area. We aim at performing in-silico experimentation to reproduce the geophysical responses of the geothermal reservoir. The model is based on the MOOSE/GOLEM framework (finite element approach) and integrate the public regional geological model GEORG that includes major lithologies and large-scale faults of the area. We will discuss the preliminary of coarse-grained simulations of the natural fluid circulation and fluid injections in light with the high resolution monitoring of the seismicity.
