Fig. 4
From: Earthquakes in Switzerland and surrounding regions during 2014
Fault-plane solutions based on first-motion polarities for eight events in 2014 (Biel ML 2.8 and 3.2, Stalden, Frauenfeld, Effretikon, Werdenberg, Bürglen, Cheyres; see Table 3). All stereograms are lower hemisphere, equal-area projections. Solid circles correspond to compressive first motion (up); empty circles correspond to dilatational first motion (down). The take-off angles were computed with the NonLinLoc software (Lomax et al. 2000), using the 3D velocity model of Husen et al. (2003). Grey lines show sets of acceptable solutions derived by the HASH algorithm (Hardebeck and Shearer 2002); black bold lines indicate the (preferred) average focal mechanisms of all accepted solutions; red bold lines mark the active plane as determined from high-precision relative earthquake relocations