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

The active deformation field acting since Early Quaternary times inthe intra-Apennine area of Central Italy was constrained through akinematic and strain analysis performed on two, independent, geologicalfault-slip and seismological data sets collected, and updated, for the areasstruck 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 EarlyQuaternary times) and instantaneous (e.g. seismological) deformationfields in the Umbria-Marche Apennines were compared in order to detectsimilarities and/or inconsistencies. The kinematic analysis pointed out asub-horizontal, NE-SW trending T-axes and a systematic coherencebetween the geological and seismological kinematic parameters, even ifrepresenting different time-scale deformations.The strain analysis further supported the extensional character of thedeformation field acting in both the investigated sectors, even if ithighlighted some heterogeneities in the strain accommodation whenconsidering individual seismogenic sources. On the whole, results pointedout the prevailing extensional character of the deformation field in CentralItaly also coherent with GPS data investigations.