Spatial variation of the b-value observed for the periods preceding and following the 24 august 2016, amatrice earthquake (ML6.0) (central Italy)

Abstract

This paper deals with a preliminary spatial and temporal analysis of the b-value variability, observed in the area where the August 2016 Amatrice earthquake (ML6.0) occurred. With comparison of the preand postperiods of the mainshock, an investigation of anomalous zone of b-values was performed aiming to find possible links with barriers and/or asperities in the crustal volume where seismic sequence was developed. Preliminary results show an area with high b-value (b=1.6) where the mainshock originated. Conversely, two low bvalue (b=0.8) volumes are located at the border of the seismogenic structure. The location of these two areas is consistent with a preliminary fault slip inversion, suggesting the presence of two highly stressed patches of co-seismic deformation located NW and SE of the mainshock, with a high potentiality to rupture causing a possible moderate or larger event: the first one in the North (Norcia), the second one in South, next to the area of Amatrice and Campotosto.