Focal mechanism maps for Western France. Symbols as in Figure 4. (a) Stereographic projections (lower hemisphere) of focal mechanisms. (b) Grid-average faulting style. (c) and (d) Grid-average orientations of near-horizontal P and T axes. Orange bars in (c) show in-situ maximum horizontal compressive stress orientations (Paquin et al., 1978). Thin black lines in (a)–(d) show geological and potentially active faults (Baize et al., 2013; Jomard et al., 2017). White dashed ellipses in (a)–(d) show areas of peculiar patterns discussed in the text. SASZ: South Armorican Shear Zone.