Seismicity and seismotectonics of the Albstadt Shear Zone in the northern Alpine foreland

Abstract. The region around the town Albstadt, SW Germany, was struck by four damaging earthquakes with magnitudes greater than 5 during last century. These occurred along Albstadt Shear Zone (ASZ), which is characterized more or less continuous microseismicity. As there are no visible surface ruptures that may be connected to fault zone, we study its characteristics seismicity distribution and faulting pattern. We use earthquake data of state service Baden-Württemberg from 2011 2018 complement it additional phase picks beginning in 2016 at AlpArray StressTransfer seismic networks vicinity ASZ. This extended set used determine new minimum 1-D vp vs velocity models corresponding station delay times for relocation. Fault plane solutions determined selected events, principal stress directions derived. have a simple stable layering increasing depth upper crust. can explained well lateral variation crystalline basement. relocated events align about north–south most activity between towns Tübingen east 9? E meridian. separated into several subclusters indicate segmentation majority 25 feature an NNE–SSW strike but NNW–SSE-striking planes also observed. main associated ASZ dips steeply, rake indicates mainly sinistral strike-slip, find minor components normal reverse faulting. direction maximum horizontal 140–149? good agreement prior studies. Down ca. 7–8 km SHmax bigger SV; below this depth, SV component. field area generated regional plate driving forces Alpine topography.