Fig. 4: Stress progression on the main fault.

The increment of the shear stress on the faults of the 2019 earthquake caused by the tectonic forces (blue line; exaggerated vertical scale), starting from the previous (unknown) earthquake, and by the Le Teil quarry activity (0.19 MPa; gray line). The anthropogenic shear stress is computed at the point marked by the small black square in Fig. 3. The total shear stress on the fault is represented by the red line. The horizontal gray line on top marks the fault strength.