Le note di letteratura contenute nel database DISS.
In blu la parte specifica sul tratto Amatrice-Accumoli.
This Composite Seismogenic Source straddles a section of the Umbria-Marche Apennines between the Upper Potenza River valley and the Campotosto Lake (from north to south), along the backbone of the Northern Apennines down to the western foothills of the Gran Sasso mountain range. This low-angle, SW-dipping normal fault system is the easternmost of the central Apennines, just west of the region where compressional activity prevails, in the eastern portion of the central and northern Apennines.
Historical and instrumental catalogues (Boschi et al., 2000; Gruppo di Lavoro CPTI, 2004; Pondrelli et al., 2006; Guidoboni et al., 2007) show a very dense intermediate (4.5 < Mw 5.0) to damaging seismicity within the area. Furthermore, this source has generated numerous destructive earthquakes, including (from north to south): 23 April 1593 (Mw 5.5, Gubbio), the possibly twin earthquakes of 14 Apr 1747 (Mw 5.9, Fiuminata) and 27 July 1751 (Mw 6.3, Gualdo Tadino), 30 April 1279 (Mw 6.3, Camerino), and the well known twin earthquakes that hit the areas of Colfiorito and Sellano in the Umbro-Marchigiano Apennines on 26 September and 14 October 1997 (Mw 5.8 and 5.7, respectively). The 14 February 1838 (Mw 5.6, Valnerina), 1 January 1328 (Mw 6.4, Norcia), and 14 January 1703 (Mw 6.8, Appennino Reatino) earthquakes have occurred south of this source.
Finally, the southernmost reaches of this source have been the locus of a sequence following the 6 April 2009, L'Aquila mainshock, including a large aftershock that occurred on 9 April 2009.
This source results from the extensive studies that followed the well known 1997 sequence, concerning both the field evidence of present-day tectonic deformation and the seismological data. Various investigators addressed the active tectonics and, subsequently, the seismogenic characteristics of the area, with widely divergent interpretations. On the one hand Cello et al. (1997, 1998) interpreted the observed ground ruptures as coseismic surface faulting, particularly in the Colfiorito basin. On the other hand, Basili et al. (1998) concluded that such ruptures were due to ground shaking, whereas the surface breaks found in the Sellano area could be ascribed to genuine surface faulting. Cinti et al. (1999) found a set of three parallel surface ruptures that they interpreted as being consistent the tectonic style of the area.
Along the southern portion of the source lies the Norcia-Cittareale Fault, which according to Blumetti (1995) and Cello et al. (1998), among others, is responsible for the 14 January 1703 earthquake, the northernmost shock of a large sequence that ruptured a 60 km-long stretch of the Centra Apennines seismogenic zone. Other portions of this source have been associated with key destructive earthquakes that have occurred in this area.
The strike of this source was selected based on that of the mapped structures (N130¡-150¡). The estimation of the dip relies on geological and seismological data (35¡-55¡). The rake is representative of pure extension and was based on geological and seismological observations (260¡-280¡). Also the minimum and maximum depth were based on geological and seismological data (2.5 and 14.0 km, respectively). The slip rate was inferred from geological observations along adjacent structures that share the same tectonic environment with the Colfiorito-Campotosto Source (0.1 - 1.0 mm/y). The maximum magnitude was taken from the largest Individual Source associated with it (Mw 6.5).
