Rupture features of the 2016 M_w 6.2 Norcia earthquake and its possible relationship with strong seismic hazards

Abstract

For analyzing possible reasons for the heavy damage and seismogenic features of the 24 August 2016 Norcia earthquake, we constructed and analyzed its rupture process by incorporating data sets of near‐field strong‐motion, teleseismic and static GPS displacements. The optimized model revealed a relatively compact slip pattern with mainly normal fault components. The maximum slip was around 0.9 m, while the rupture areas extended ~11 km and ~20 km along dip and strike, respectively. The total seismic moment was 2.3 × 1018 Nm, equivalent to Mw 6.2. Most seismic moments were released within 10 s, radiating 3.5 × 1013 J of seismic energy. The rupture history showed asymmetric propagation and is characterized by a relatively high rupture velocity within the first 6 s with a maximum of ~3.2 km/s. The main shock slip pattern correlated well with the aftershocks distribution, and most of the accumulated strain was released in the east of seismic gap between the nearby 1997 and 2009 earthquake sequences.

Source Parameters of the 2016–2017 Central Italy Earthquake Sequence from the Sentinel-1, ALOS-2 and GPS Data

“…For the 2016 Amatrice earthquake, the distributed slip model shows two main distinctive asperities due to the lateral heterogeneity of the friction coefficient on the fault [2][3][4]. Our inverted result is consistent with previous studies [2][3][4][5][6][7].…”

“…Our inverted result is consistent with previous studies [2][3][4][5][6][7]. Because the GPS and InSAR data can provide independent constraints on the fault parameters in this study, the location of the fault rupture should be more accurate.…”

“…The predominant slip occurred on the fault with a peak magnitude of 2.5 m at a depth of 0-6 km, which suggests that the rupture reached the surface (Figure 7). The result is consistent with other papers [3,6,7]. …”

“…The total released geodetic moment is approximately 2.16 × 10 18 Nm (Mw 6.2), and the majority of slip occurred on the fault with a peak magnitude of 1.26 m at a depth of 5-6 km ( Figure 3). The best-fitting slip model consists of two distinct slip patches located beneath the two observed lobes of deformation, in agreement with the previous studies [2][3][4][5][6][7]. The average slip errors are approximately 2.6 cm, except for the area down-dip from the left asperity, where the error increases to 14 cm, which can be attributed to reduced measurement constraints.…”

Geodetic model of the 2016 Central Italy earthquake sequence inferred from InSAR and GPS data

“…The fault geometry of the source responsible for the 24 August earthquake has already been investigated by inverting geodetic [Bignami et al, 2016;Cheloni et al, 2016;Lavecchia et al, 2016;Huang et al, 2017] and seismological [Tinti et al, 2016;Liu et al, 2017] data. Compared with the previous studies, we used an augmented geodetic data set, consisting of five InSAR interferograms and of the full set of GPS displacements.…”