Abstract

We investigate the possibility of inferring the dominant horizontal‐rupture direction for moderate earthquakes from the inversion of peak ground‐motion parameters. To this aim, we adopt a technique that was devised and applied to large earthquakes for retrieving both the dominant rupture direction and the surface fault projection to be used with a proper distance metric to refine the ShakeMap computation. In the present paper, the procedure was applied to three moderate earthquakes that occurred in 2012 in Northern Italy three days apart: the M 4.2 Pre‐Alpi Venete earthquake on 24 January, the M 4.9 Reggio Emilia earthquake on 25 January, and the M 5.4 Parma earthquake on 27 January. For two of the three analyzed events, the technique identifies a dominant horizontal‐rupture direction, which is consistent with the strike directions inferred from the focal mechanisms. For the M 5.4 event, which is a deep (about 61 km) thrust‐faulting mechanism earthquake, the inferred dominant rupture direction allows identification of the northeast‐dipping plane as the fault plane in accordance with the aftershocks distribution.

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