Small magnitude earthquake sequences and seismic swarms in the Northern Apennines (central Italy): new observations from the analysis of Montefeltro seismicity

Abstract

We collected P and S phases from 516 earthquakes. Earthquakes were integrated with new pickings selected from the temporary array and relocated using the Hypoellipse code [Lahr, 1999]. The 1-D velocity model used in this work is based on the study by Santini et al. [2011], which was determinated for the solution of focal mechanisms of central-northern Marche. To constrain the subcrustal seismicity of the area, we added the layers between 35 and 100 km to link the structure of crustal velocity with the superficial part of the upper mantle, as defined in the spherical global models such as iasp91, ak135 [Kennett et al., 1995]