Contrasting surface active faults and deep seismogenic sources unveiled by the 2009 L’Aquila earthquake sequence (Italy)

Bigi, Sabina; Casero, P.; Chiarabba, C.; Bucci, Daniela Di

doi:10.1111/ter.12000

Cited by 33 publications

(48 citation statements)

References 26 publications

(30 reference statements)

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“…Geodetic data show that the sequence evolved along a main SW dipping normal fault system, relative to the MGVB alignment. The 24 August M w 6.1 main shock ruptured two distinct segments of this fault system (Figure 4a), corresponding to the northern part of the~50°SW dipping Mount Gorzano Fault, which was partially activated in its southern portion during the 2009 L'Aquila earthquake [Chiaraluce et al, 2011;Bigi et al, 2013;Cheloni et al, 2014], and to the southern part of the~40°SW-dipping Mount Vettore Fault, respectively. The main shock occurred, with a bilateral rupture, between these two fault segments, possibly merging into a single SW dipping structure at the hypocentral depth [Lavecchia et al, 2016;Tinti et al, 2016;Chiaraluce et al, 2017].…”

Section: Discussionmentioning

confidence: 99%

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

Cheloni

Novellis

Albano

et al. 2017

Geophysical Research Letters

168

255

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We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR) and GPS measurements to determine the source parameters for the three main shocks of the 2016 Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw 6.1, 5.9, and 6.5, respectively). Our preferred model is consistent with the activation of four main coseismic asperities belonging to the SW dipping normal fault system associated with the Mount Gorzano‐Mount Vettore‐Mount Bove alignment. Additional slip, equivalent to a Mw ~ 6.1–6.2 earthquake, on a secondary (1) NE dipping antithetic fault and/or (2) on a WNW dipping low‐angle fault in the hanging wall of the main system is required to better reproduce the complex deformation pattern associated with the greatest seismic event (the Mw 6.5 earthquake). The recognition of ancillary faults involved in the sequence suggests a complex interaction in the activated crustal volume between the main normal faults and the secondary structures and a partitioning of strain release.

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Section: Discussionmentioning

confidence: 99%

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

Cheloni

Novellis

Albano

et al. 2017

Geophysical Research Letters

168

255

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“…Although Bigi et al () estimated a maximum cumulative offset of about 1,000 m for this fault, a detailed timing of fault activity remains uncertain. Its surface expression and activity and the connection with deep structures and relationship with the seismicity have been discussed and questioned in the recent literature (Bigi et al, , ; Improta et al, ). The MLGf encompasses the northern segment of the 2009 L'Aquila seismic sequence (i.e., Campotosto segment in Valoroso et al, ) and the southern termination of the normal fault system activated on August 2016 during the 2016–2017 central Italy one.…”

Section: Geologic Outlinementioning

confidence: 99%

Tectonics Inversions, Fault Segmentation, and Triggering Mechanisms in the Central Apennines Normal Fault System: Insights From High‐Resolution Velocity Models

et al. 2018

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The potential role of subsequent tectonic phases in reworking inherited geological structures is a key issue to unravel the seismotectonics of an area. This has a direct connection with fault segmentation, earthquakes maximum magnitude, and strong implications for seismic hazard assessment. The central Apennines (Italy) represent an exemplary case, since it developed because of the overprint of different deformational phases, producing potential conditions for episodic tectonic inversions and a very complex structural architecture. In this paper, we show how inherited compressional structures, still dominating the Apennines belt architecture, interfere with the active extension, having a direct connection with active seismotectonics. We present seismicity and new velocity tomograms of an 80‐km‐long section of the normal fault system activated during the 2009 and 2016–2018 seismic sequences. The joint interpretation highlights how the extensional seismic sequences partially reactivated inherited compressive structures, which have not an undisputable relationship with the surficial geological setting. Complexity deriving from the irregular geometry of normal faults and inverted thrust ramps is responsible for the observed intense fragmentation of the extensional system. Fluid overpressure seems to be a viable mechanism behind the partial remobilization of unbroken segments of the fault system.

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“…The discovery of Triassic evaporites drilled in the core of the Burano anticline (Umbria‐Marche basin, northern Apennines) drove balanced cross sections to image Mesozoic sequences detached along Triassic evaporites and stacked over an undisturbed basement of Permian clastics (exposed in Tuscany) and speculative crystalline rocks. Although the thin‐skinned model has been widely accepted [ Bigi et al ., , ] and also applied for the northern and southern Apennines [ Bally et al ., ; Mostardini and Merlini , ], other contrasting tectonic styles have been subsequently postulated.…”

Section: Exposed Lithologies and Tectonic Styles Of The Central Apennmentioning

confidence: 99%

Ultra‐thick Triassic dolomites control the rupture behavior of the central Apennine seismicity: Evidence from magnetic modeling of the L'Aquila fault zone

Speranza

Minelli

2014

JGR Solid Earth

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High-resolution tomography from the 2009 L' Aquila extensional seismic sequence has shown that the Mw 6.1 main shock and most of the aftershocks occurred within a high velocity body (6.6 ≤ Vp ≤ 6.8 km/s), located between depths of 3 and 12 km. The nature of the high-Vp body has remained speculative, although exhumed mafic deep crustal and upper mantle rocks (serpentinites) have been favored. We used 3D magnetic anomaly modeling to investigate the plausibility of these favored sources for the L' Aquila body. The modeling does not support the presence of high-velocity serpentinites with a 30-50% serpentinization degree and gabbros. Accordingly, we conclude that the high-Vp body may represent non-magnetic upper Triassic and possibly lower Liassic dolomites that have been drilled in neighboring wells for 2-4 km. This conclusion is also consistent with the lack of a coherent gravity anomaly for the body. We speculate that ultra-thick Triassic dolomites reaching a thickness of 8 km may have been deposited in syntectonic wedges formed at the northern margin of the Ionian Sea, where oceanic spreading occurred in mid-late Triassic times.

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Contrasting surface active faults and deep seismogenic sources unveiled by the 2009 L’Aquila earthquake sequence (Italy)

Cited by 33 publications

References 26 publications

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

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

Tectonics Inversions, Fault Segmentation, and Triggering Mechanisms in the Central Apennines Normal Fault System: Insights From High‐Resolution Velocity Models

Ultra‐thick Triassic dolomites control the rupture behavior of the central Apennine seismicity: Evidence from magnetic modeling of the L'Aquila fault zone

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