Active deformation field from earthquakes and faults in the Colfiorito 1997 and L’Aquila 2009 seismic sequence epicentral areas (central Italy)

Federica Ferrarini (a), Giusy Lavecchia (a), Rita de Nardis (a,b), Francesco Brozzetti (a) & Maria Adelaide Romano (a)
(a) Laboratorio di Geodinamica e Sismogenesi, DiS.P.U.Ter, Università "G. d'Annunzio", Campus Universitario, 66013 Chieti Scalo, Chieti, Italy. E-mail: f.ferrarini@unich.it (b) Dipartimento della Protezione Civile, Rome, Italy.

The active deformation field acting since Early Quaternary times in the intra-Apennine area of Central Italy was constrained through a kinematic and strain analysis performed on two, independent, geological fault-slip and seismological data sets collected, and updated, for the areas struck by the two most energetic seismic sequences of the last fifteen years (Colfiorito 1997, Mw6.0 and L’Aquila 2009, Mw6.1). The attitude and shape of the long-term (e.g. geological, since Early Quaternary times) and instantaneous (e.g. seismological) deformation fields in the Umbria-Marche Apennines were compared in order to detect similarities and/or inconsistencies. The kinematic analysis pointed out a sub-horizontal, NE-SW trending T-axes and a systematic coherence between the geological and seismological kinematic parameters, even if representing different time-scale deformations. The strain analysis further supported the extensional character of the deformation field acting in both the investigated sectors, even if it highlighted some heterogeneities in the strain accommodation when considering individual seismogenic sources. On the whole, results pointed out the prevailing extensional character of the deformation field in Central Italy also coherent with GPS data investigations.

kinematic analysis, strain ellipsoid, active deformation field, Central Italy