The 1762 October 6 earthquake in the Middle Aterno Valley (L'Aquila, Central Italy): new constraints and new insights

Abstract

The effort for reducing the uncertainties in the location and size of historical earthquakes, even moderate-size ones, is not a peripheral issue, as it plays a major role in the distribution of earthquake recurrence times that can affect the maps of seismic hazard of a territory. The L‟Aquila area (Abruzzo, Central Italy) struck by the April 6, 2009 Mw 6.3 seismic event is a typical example of an earthquake-prone region the location of whose historical seismicity needs to be better located. Thanks to a large body of geological, seismological and geodetic evidence the deep source of the 2009 mainshock has been imaged as a ~15 km-long, NW-trending, SWdipping, almost pure normal fault coinciding with the Paganica Fault accepted_Manuscript Click here to download Manuscript: accepted_source_file.doc 2 System at the surface (Fig. 1). Conversely, very few papers have addressed so far the issue of reconstructing the seismic history of the Paganica Fault, charting the relationships between this fault and the adjacent ones, and finding out the causative source for each of the earthquakes listed in the Italian earthquake Catalog (CPTI Working Group, 2004; Rovida et al., 2011).