Imaging the polarity switch between large seismogenic normal faults in the southern Apennines (Italy)

Abstract

The transition between the central and southern Apennines (Italy) is marked, among other regional features, by a dramatic shift (from SW-dipping to NE-dipping) of the vergence of the large (more than 25 km long) seismogenic normal faults, responsible for M>6 pre-historical and historical earthquakes. Also, in the exact area where such accommodation occurs, in 2005 a low magnitude (M<3) seismic sequence took place along a short stretch of a long-lived transverse structure running across this transition zone. We believe this sequence sheds light on the geometry and the role of the interaction between these seismogenic domains.