GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 1.2 125 We compared the strike of selected seismogenic faults (normal and reverse) with the direction inferred from the eigenvectors of the strain rate tensor. Gemona is associated with the 1976 Mw=6.5 event, Colfiorito is associated with the 1997 Mw=6.0 event, Paganica with the 2009 Mw=6.3 event, Mirandola and Finale Emilia with the dual 2012 Mw=6.1 events and Amatrice with the 2016 Mw=6.0 event. For this last source we have assumed as principal plane the SW dipping. Considering that the overall uncertainty in the strike angles is of the order of 20-30 degrees, we conclude that the geologically determined angles are consistent with the directions of maximum strain rate, at least for these structures. As shown in Fig. 1, in NE Italy the the alignment is very close only near the tip of the indenter where Gemona (ITIS120) is located. Further west and east the compressional eigenvector clearly rotates less than the strike of the structures. Conclusion. The coupling between a regional stress rate field implied by GPS data and the fault geometry described in the DISS provide important quantitative information on the loading/unloading of potentially active seismogenic sources. Our analysis provides a first quantitative scale for this mechanical coupling. Sources located in NE Italy, were the Adria Fig. 3 - Classification of the selected ISS’s according to their CFF. The area in central Italy of Aquila and Avezzano appears the one with the maximum loading rate. Squares indicate the epicenters of historical earthquakes, according to the CPTI2015 catalogue (Rovida et al. , 2016).