Fig. 4

Synthetic focal-mechanism main groups and sub-groups for microseismic events in the sedimentary cover. The orientation of 234 faults and striations in the sedimentary cover were measured during the excavation of the Mont Terri rock laboratory (Nussbaum et al. 2011). Out of a total dataset of 234 fault/striation pairs, 227 were used to determine different main groups and sub-groups. These sub-groups determine the synthetic focal mechanisms composed of two nodal planes in which the bold great circle indicates the fault plane and the thin great circle shows the auxiliary plane