Faults geometry and the role of fluids in the 2016-2017 Central Italy seismic sequence

Chiarabba, C.; De Gori, P.; Cattaneo, M.; Spallarossa, D.; Segou, M.. 2018 Faults geometry and the role of fluids in the 2016-2017 Central Italy seismic sequence. Geophysical Research Letters, 45 (14). 6963-6971. 10.1029/2018GL077485

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Official URL: http://dx.doi.org/10.1029/2018GL077485

Abstract/Summary

The 2016–2017 Central Italy seismic sequence ruptured overlapping normal faults of the Apennines mountain chain, in nine earthquakes with magnitude Mw > 5 within a few months. Here we investigate the structure of the fault system using an extensive aftershock data set, from joint permanent and temporary seismic networks, and 3‐D Vp and Vp/Vs velocity models. We show that mainshocks nucleated on gently west dipping planes that we interpret as inverted steep ramps inherited from the late Pliocene compression. The two large shocks, the 24 August, Mw = 6.0 Amatrice and the 30 October, Mw = 6.5 Norcia occurred on distinct faults reactivated by high pore pressure at the footwall, as indicated by positive Vp/Vs anomalies. The lateral extent of the overpressurized volume includes the fault patch of the Norcia earthquake. The irregular geometry of normal faults together with the reactivated ramps leads to the kinematic complexity observed during the coseismic ruptures and the spatial distribution of aftershocks.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2018GL077485
ISSN:	00948276
Date made live:	23 Nov 2018 14:55 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/521678

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/2018GL077485

ISSN:

00948276

Date made live:

23 Nov 2018 14:55 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/521678