Active shallow extension in central and eastern Betic Cordillera from CGPS data

Galindo-Zaldı́var, Jesús; Gil, A. J.; Galdeano, Carlos Sanz de; Lacy, M. C.; García-Armenteros, Juan Antonio; Ruano, Patricia; Ruiz, Antonio M.; Martínez-Martos, Manuel; Alfaro, P.

doi:10.1016/j.tecto.2015.08.035

Cited by 38 publications

(86 citation statements)

References 70 publications

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“…This regional deformation produces a NNW‐SSE shortening, which, in the central part of the Alboran Sea, may be constrained by the MALA and ALME stations in Spain and by MELI station in Morocco (Figure ). The higher rates of MALA station with respect to ALME evidence ENE‐WSW extension in the Betic Cordillera (Galindo‐Zaldivar, Gil, et al, ). The southern displacement of ALME and MALA stations relative to the European Plate contrasts with the northern displacement of MELI, supporting present‐day shortening in the central Alboran Sea.…”

Section: Resultsmentioning

confidence: 99%

Imaging the Growth of Recent Faults: The Case of 2016–2017 Seismic Sequence Sea Bottom Deformation in the Alboran Sea (Western Mediterranean)

et al. 2018

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The Eurasian-African NW-SE oblique plate convergence produces shortening and orthogonal extension in the Alboran Sea Basin (westernmost Mediterranean), located between the Betic and Rif Cordilleras. A NNE-SSW broadband of deformation and seismicity affects the Alboran central part. After the 1993-1994 and 2004 seismic series, an earthquake sequence struck mainly its southern sector in 2016-2017 (main event M w = 6.3, 25 January 2016). The near-surface deformation is investigated using seismic profiles, multibeam bathymetry, gravity and seismicity data. Epicenters can be grouped into two main alignments. The northern WSW-ENE alignment has reverse earthquake focal mechanisms, and in its epicentral region recent mass transport deposits occur. The southern alignment consists of a NNE-SSW vertical sinistral deformation zone, with early epicenters of higher-magnitude earthquakes located along a narrow band 5 to 10-km offset westward of the Al Idrisi Fault. Here near-surface deformation includes active NW-SE vertical and normal faults, unmapped until now. Later, epicenters spread eastward, reaching the Al Idrisi Fault, characterized by discontinuous active NNE-SSW vertical fractures. Seismicity and tectonic structures suggest a westward propagation of deformation and the growth at depth of incipient faults, comprising a NNE-SSW sinistral fault zone in depth that is connected upward with NW-SE vertical and normal faults. This recent fault zone is segmented and responsible for the seismicity in 1993-1994 in the coastal area, in 2004 onshore, and in 2016-2017 offshore. Insights for seismic hazard assessment point to the growth of recent faults that could produce potentially higher magnitude earthquakes than the already formed faults.

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Section: Resultsmentioning

confidence: 99%

Imaging the Growth of Recent Faults: The Case of 2016–2017 Seismic Sequence Sea Bottom Deformation in the Alboran Sea (Western Mediterranean)

et al. 2018

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“…We consider that the model of Palano et al () best explains the geological observations, seismicity, and detailed GPS data recently obtained from local networks (Echeverria et al, , , and data presented in this work). Geological, seismological, and geodetic data indicate that the central and Eastern Betic Cordillera are two different tectonic domains (De Larouzière et al, ; Echeverria et al, , ; Galindo‐Zaldívar et al, ; Silva et al, , among many others). Presently, the central sector is dominated by extension, while the eastern sector is dominated by oblique strike‐slip and reverse tectonics along the EBSZ.…”

Section: Discussionmentioning

confidence: 99%

How Much Nubia‐Eurasia Convergence Is Accommodated by the NE End of the Eastern Betic Shear Zone (SE Spain)? Constraints From GPS Velocities

et al. 2019

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We present the first GPS‐derived geodetic observations from the NE end of the Eastern Betic Shear Zone obtained from the Bajo Segura GPS network (SE Spain). The network has 11 GPS sites and was sampled four times between 1999 and 2013. Despite the low signal‐to‐noise ratio of the residual velocities obtained, the velocities are nonzero at 95% confidence level. We postulate that the GPS data point to the partitioning of deformation into the NNW–SSE shortening and a N70E left‐lateral component. The maximum deformation rates are located along the two main active faults in the study area. The maximum shortening rates (north component) in the southern region of the Bajo Segura Basin vary from west to east, ranging from 0.2 to 0.7 mm/year along the Bajo Segura Fault Zone. On the northern border of the basin, along the Crevillente Fault Zone, left‐lateral displacement varies between 0.4 and 0.7 mm/year in the E‐W direction. The GPS‐based regional geodynamic models of the Western Mediterranean indicate that the residual shortening of the Eurasia‐Nubia plate convergence is accommodated in the eastern part of the Iberian Peninsula and the Algero‐Balearic Basin. Our results indicate that part of this residual deformation occurs at the NE end of the Eastern Betic Shear Zone, but significant deformation must be accommodated also to the north (External Betics) and to the south (Cartagena Basin and offshore area). We postulate that Eurasia‐Nubia plate convergence is transferred to the Eastern Betics because of the thin and rigid (potentially oceanic) crust of the Algero‐Balearic Basin, which acts as an indenter.

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“…The geometry of the right lateral fault is not to be demonstrated. A right-lateral strike-slip fault zone exists onshore in the Beti,c accommodating the extrusion of the Betic-Rif tectonic domain (Galindo-Zaldivar et al, 2015;Gonzalez-Castillo et al, 2015). The continuity of this right lateral fault zone toward the East is complex because it seems to form a triple junction with the Carboneras and Palomares fault zones.…”

Section: Discussion Papermentioning

confidence: 99%

answer to the referee 2

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Active shallow extension in central and eastern Betic Cordillera from CGPS data

Cited by 38 publications

References 70 publications

Imaging the Growth of Recent Faults: The Case of 2016–2017 Seismic Sequence Sea Bottom Deformation in the Alboran Sea (Western Mediterranean)

Imaging the Growth of Recent Faults: The Case of 2016–2017 Seismic Sequence Sea Bottom Deformation in the Alboran Sea (Western Mediterranean)

How Much Nubia‐Eurasia Convergence Is Accommodated by the NE End of the Eastern Betic Shear Zone (SE Spain)? Constraints From GPS Velocities

answer to the referee 2

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