A soft linkage between major seismogenic fault systems in the central-southern Apennines (Italy): Evidence from low-magnitude seismicity

Fracassi, Umberto; Milano, Girolamo

doi:10.1016/j.tecto.2014.08.002

Cited by 8 publications

(4 citation statements)

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“…The crustal structure of these deep strike-slip seismogenic sources is scarcely known. In the current debate, E-W strike-slip faults have been interpreted either as second-order transfer faults between NW-SE trending master normal faults, or as primary lithospheric ruptures of the Adria plate [11,34,[89][90][91][92]. The fault plane solutions computed in this study provide a useful tool for further studies and may yield additional constraints on regional geodynamic and seismotectonic models.…”

Section: San Marco La Catola and Foiano In Val DI Fortore Clusters: Ementioning

confidence: 95%

“…To the east and the northeast of the Matese massif, within the Adria plate, E-W strike-slip faults of moderate-to-low seismicity were observed [42,43]. Many authors consider these structures as potential seismogenic sources of moderate-to-large magnitude events [34,44] as shown in Figure 2 (red dashed ellipse) for the presumed subevent of the 1456 sequence.…”

Section: Introductionmentioning

confidence: 99%

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The 2013–2018 Matese and Beneventano Seismic Sequences (Central–Southern Apennines): New Constraints on the Hypocentral Depth Determination

et al. 2019

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The Matese and Beneventano areas coincide with the transition from the central to the southern Apennines and are characterized by both SW- and NE-dipping normal faulting seismogenic structures, responsible for the large historical earthquakes. We studied the Matese and Beneventano seismicity by means of high-precision locations of earthquakes spanning from 29 December 2013 to 4 September 2018. Events were located by using all of the available data from temporary and permanent stations in the area and a 1D computed velocity model, inverting the dataset with the Velest code. For events M > 2.8 we used P- and S-waves arrival times of the strong motion stations located in the study area. A constant value of 1.83 for Vp/Vs was computed with a modified Wadati method. The dataset consists of 2378 earthquakes, 18,715 P- and 12,295 S-wave arrival times. We computed 55 new fault plane solutions. The mechanisms show predominantly normal fault movements, with T-axis trends oriented NE–SW. Only relatively small E–W trending clusters in the eastern peripheral zones of the Apenninic belt show right-lateral strike-slip kinematics similar to that observed in the Potenza (1990–1991) and Molise (2002 and 2018) sequences. These belong to transfer zones associated with differential slab retreat of the Adriatic plate subduction beneath the Apennines. The Matese sequence (December 2013–February 2014; main shock Mw 5.0) is the most relevant part of our dataset. Hypocentral depths along the axis of the Apenninic belt are in agreement with previous seismological studies that place most of the earthquakes in the brittle upper crust. We confirm a general deepening of seismicity moving from west to the east along the Apennines. Seismicity depth is controlled by heat-flow, which is lower in the eastern side, thus causing a deeper brittle–ductile transition.

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Section: San Marco La Catola and Foiano In Val DI Fortore Clusters: Ementioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

The 2013–2018 Matese and Beneventano Seismic Sequences (Central–Southern Apennines): New Constraints on the Hypocentral Depth Determination

et al. 2019

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“…Fault data were collected using only peer‐reviewed sources of structural, geological, and seismological data. We presume a fault to be active if there exists evidence of tectonic activity in the Late Pleistocene‐Holocene deriving from the following: seismicity investigations (Bonini et al, 2016; Cucci et al, 1996; Esposito et al, 1987; Fracassi & Milano, 2014; Gasperini et al, 1999; Guidoboni et al, 2019; Pace et al, 2002; Westaway et al, 1989, among several others); investigations of continental deposits and landforms (Bagnaia et al, 1992; Bertini & Bosi, 1993; Brancaccio et al, 1997; Boncio et al, 2010; Carraro & Giardino, 1992; Cavinato et al, 2002; Corrado et al, 1997; Di Bucci et al, 2002, 2005, 2011; Falcucci et al, 2009; Galadini & Messina, 1993, 1994; Galadini et al, 1998; Giraudi, 1994; Gori et al, 2011; Pizzi et al, 2010; Saroli & Moro, 2012; Saroli et al, 2014; Vittori et al, 1995, among several others) or paleoseismological investigations (Ceccaroni et al, 2009; D'Addezio et al, 2001; Frezzotti & Giraudi, 1989; Galadini & Galli, 1999, 2003; Galli et al, 2011, 2015; Galli & Galadini, 2003; Giraudi, 1989; Giraudi & Frezzotti, 1995; Michetti et al, 1996; Moro et al, 2013; Pantosti et al, 1996; Salvi et al, 2003). …”

Section: Active Tectonics Datamentioning

confidence: 99%

Partitioning the Ongoing Extension of the Central Apennines (Italy): Fault Slip Rates and Bulk Deformation Rates From Geodetic and Stress Data

et al. 2020

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We investigated whether the joint inversion of geodetic and stress direction data can constrain long‐term fault slip rates in the central Apennines, and ultimately how extension is partitioned among fault slip and bulk lithosphere permanent strain. Geodetic velocities are collected in the fault interseismic stage with steady secular deformation; thus, long‐term estimates can be derived with a model of elastically unloading seismogenic faults within a viscously deforming lithosphere. As the average spacing of permanent Global Navigation Satellite Systems (GNSS) stations is similar to the average length of seismogenic faults (25–35 km), if not larger, we decided to merge permanent and temporary GNSS measurements, resulting in a denser geodetic data set. Given that most normal faults in the Apennines have slip rates around or below 1 mm/a, and most campaign GNSS velocities carry similar uncertainties, simple local back slip models cannot be applied. More sophisticated modeling is required to extract reasonable bulk deformation rates and long‐term fault slip rates at signal‐to‐noise ratio of order unity. Given the spatial distribution of the GNSS network, we estimated the long‐term slip rate of seven major fault systems that are in satisfactory agreement with available geological slip rates. The resulting spatial distribution of bulk deformation rates locally fits short‐term transients; in other cases, they represent the currently unclear signature of tectonic processes like upper‐crustal viscoplastic deformation and aseismic slip, or indicate missing faults in the adopted database. We conclude that the time is ripe for determining fault slip rates using geodetic and stress direction data, particularly where fault activity rates are hard to determine geologically.

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“…An example of Apennine chain-transverse fault that can act as barrier to hinder fault rupture propagation has been proposed by Pace et al (2002), dealing with the source of the M s 5.8 1984 Sangro Valley earthquake. According to Fracassi and Milano (2014), the regional tectonic structure known as the Ortona-Roccamonfina Line allowed soft linkage between active faults across it, as well as the shift of fault dip direction, that is SW-ward and NE-ward, north and south of the Line, respectively.…”

Section: Introductionmentioning

confidence: 99%

Active faulting, 3-D geological architecture and Plio-Quaternary structural evolution of extensional basins in the central Apennine chain, Italy

et al. 2017

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Abstract. The general basin and range Apennine topographic characteristic is generally attributed to the presently active normal fault systems, whose long-term activity (throughout the Quaternary) is supposed to have been responsible for the creation of morphological/structural highs and lows. By coupling field geological survey and geophysical investigations, we reconstructed the 3-D geological model of an inner tectonic basin of the central Apennines, the Subequana Valley, bounded to the northeast by the southern segment of one of the major active and seismogenic normal faults of the Apennines, known as the Middle Aterno Valley–Subequana Valley fault system. Our analyses revealed that, since the late Pliocene, the basin evolved in a double half-graben configuration through a polyphase tectonic development. An early phase, Late Pliocene–Early Pleistocene in age, was controlled by the ENE–WSW-striking and SSE-dipping Avezzano–Bussi fault, that determined the formation of an early depocentre towards the N–NW. Subsequently, the main fault became the NW–SE-striking faults, which drove the formation during the Quaternary of a new fault-related depocentre towards the NE. By considering the available geological information, a similar structural evolution has likely involved three close tectonic basins aligned along the Avezzano–Bussi fault, namely the Fucino Basin, the Subequana Valley, and the Sulmona Basin, and it has been probably experienced by other tectonic basins of the chain. The present work therefore points out the role of pre-existing transverse tectonic structures, inherited by previous tectonic phases, in accommodating the ongoing tectonic deformation and, consequently, in influencing the structural characteristics of the major active normal faults. This has implications in terms of earthquake fault rupture propagation and segmentation. Lastly, the morpho-tectonic setting of the Apennine chain results from the superposition of deformation events whose geological legacy must be considered in a wider evolutionary perspective. Our results testify that a large-scale basin and range geomorphological feature – often adopted for morpho-tectonic and kinematic evaluations in active extensional contexts, as in the Apennines – just led by range-bounding active normal faults may be actually simplistic, as it could not be applied everywhere, owing to peculiar complexities of the local tectonic histories.

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A soft linkage between major seismogenic fault systems in the central-southern Apennines (Italy): Evidence from low-magnitude seismicity

Cited by 8 publications

References 93 publications

The 2013–2018 Matese and Beneventano Seismic Sequences (Central–Southern Apennines): New Constraints on the Hypocentral Depth Determination

The 2013–2018 Matese and Beneventano Seismic Sequences (Central–Southern Apennines): New Constraints on the Hypocentral Depth Determination

Partitioning the Ongoing Extension of the Central Apennines (Italy): Fault Slip Rates and Bulk Deformation Rates From Geodetic and Stress Data

Active faulting, 3-D geological architecture and Plio-Quaternary structural evolution of extensional basins in the central Apennine chain, Italy

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