Seismicity in Strike‐Slip Foreland Faults (Central Betic Cordillera Front): Evidence of Indentation Tectonics

Tendero-Salmerón, Víctor; Galindo-Zaldı́var, Jesús; Peláez, José A.; Martínez-Martos, Manuel; Henares, Jesús; Marín‐Lechado, Carlos; Gil, A. J.; López-Garrido, A. C.

doi:10.1029/2020tc006143

Cited by 6 publications

(7 citation statements)

References 67 publications

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“…Absolute locations, on the other hand, strongly depend on the reliability of the shear velocity model used (Waldhauser & Richards, 2004). In previous works, the same approach and code were used in the same regions, and regions nearby (Marín‐Lechado et al., 2017; Morales et al., 2015; Tendero‐Salmerón et al., 2020).…”

Section: Methodsmentioning

confidence: 99%

The Role of Faults as Barriers in Confined Seismic Sequences: 2021 Seismicity in the Granada Basin (Betic Cordillera)

et al. 2022

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Fault barriers are key structures for studying seismic hazard in regions of intense brittle deformation. The interaction between fault sets affects their seismogenic behavior, if some of them act as barriers. The Granada Basin, in the Betic Cordillera, is a region affected by shallow brittle deformation, as it was the scenario for the recent Granada 2021 seismic sequence. This seismicity presented a swarm behavior at the beginning of the sequence, followed by mainshock‐aftershock features. Geological and gravity data presented here reveal that the basement is affected by two sets of NW‐SE and NE‐SW normal faults and intensely deformed by vertical NW‐SE joints. Improved relocation of the Granada 2021 seismicity reveals a confined chimney‐shape seismicity caused by the activity of a 2 km long NW‐SE normal fault segment. The confinement of the sequence is associated with the NE‐SW fault set acting as a barrier that restricts the rupture area, limiting the maximum magnitude, and favoring the recurrence of events with smaller magnitude. The chimney‐shape of the seismic sequence suggests that the deformation is propagated vertically to the surface, facilitated by preexisting fractures. The shallow extensional deformation during the uplift of the central Betic Cordillera drove the activity of the local structures obliquely to the regional extensional trends, as evidenced by the seismic sequence. This multidisciplinary study improves the knowledge on the origin of the Granada Basin and underlies the important role of preexisting fractures on fault segmentation and seismic propagation, decreasing the seismic potential of this area.

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Section: Methodsmentioning

confidence: 99%

The Role of Faults as Barriers in Confined Seismic Sequences: 2021 Seismicity in the Granada Basin (Betic Cordillera)

et al. 2022

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“…Discussion remains alive, offering models mainly based on delamination [ 30 , 31 ] or subduction [ 32 , 33 ]; some include roll-back [ 13 , 14 , 34 , 35 , 36 ], or can be understood as hybrid models [ 37 ]. Moreover, the central Alboran Sea [ 28 ] and the eastern Betics [ 38 , 39 ] are affected by indentation tectonics that might contribute to the escape tectonics affecting the westernmost Gibraltar Arc [ 40 ]. Recent GNSS regional data ( Figure 1 ) [ 13 , 14 , 15 ] provide a new framework for interpreting present-day tectonic movements and discussing their possible underlying processes.…”

Section: Geological Settingmentioning

confidence: 99%

The Campo de Dalias GNSS Network Unveils the Interaction between Roll-Back and Indentation Tectonics in the Gibraltar Arc

Galindo-Zaldı́var

Gil

Tendero-Salmerón

et al. 2022

Sensors

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The Gibraltar Arc includes the Betic and Rif Cordilleras surrounding the Alboran Sea; it is formed at the northwest–southeast Eurasia–Nubia convergent plate boundary in the westernmost Mediterranean. Since 2006, the Campo de Dalias GNSS network has monitored active tectonic deformation of the most seismically active area on the north coast of the Alboran Sea. Our results show that the residual deformation rates with respect to Eurasia range from 1.7 to 3.0 mm/year; roughly homogenous west-southwestward displacements of the northern sites occur, while the southern sites evidence irregular displacements towards the west and northwest. This deformation pattern supports simultaneous east-northeast–west-southwest extension, accommodated by normal and oblique faults, and north-northwest–south-southeast shortening that develops east-northeast–west-southwest folds. Moreover, the GNSS results point to dextral creep of the main northwest–southeast Balanegra Fault. These GNNS results thus reveal, for the first time, present-day interaction of the roll-back tectonics of the Rif–Gibraltar–Betic slab in the western part of the Gibraltar Arc with the indentation tectonics affecting the eastern and southern areas, providing new insights for improving tectonic models of arcuate orogens.

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“…In the Eastern Betic Cordillera, the Eurasia‐Nubia convergence is effectively transferred because of a tectonic indenter (Figure 1) (Borque et al., 2019; Coppier et al., 1989; Estrada et al., 2018; Galindo‐Zaldivar et al., 2022; Palano et al., 2015; Tendero‐Salmerón, 2022). This convergence is accommodated along a transpressive tectonic corridor: the Trans‐Alboran Shear Zone (Bousquet, 1979; De Larouziere et al., 1987), also named the Eastern Betic Shear Zone (Silva et al., 2003).…”

Section: Introductionmentioning

confidence: 99%

Insights of Active Extension Within a Collisional Orogen From GNSS (Central Betic Cordillera, S Spain)

et al. 2023

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The coexistence of shortening and extensional tectonic regimes is a common feature in orogenic belts. The westernmost end of the Western Mediterranean is an area undergoing shortening related to the 5 mm/yr NNW‒SSE convergence of the Nubia and Eurasia Plates. In this region, the Central Betic Cordillera shows a regional ENE‒WSW extension. Here, we present GNSS‐derived geodetic data along a 170 km‐long transect orthogonal to the main active normal faults of the Central Betic Cordillera. Our data indicate that the total extension rate along the Central Betic Cordillera is 2.0 ± 0.3 mm/yr. Extension is accommodated in the eastern (0.8 ± 0.3 mm/yr in the Guadix‐Baza Basin) and western (1.3 ± 0.3 mm/yr in the Granada Basin) parts of the Central Betic Cordillera, while no extension is recorded in the central part of the study area. Moreover, our data permit us to quantify, for the first time, short‐term fault slip rates of the Granada Fault System, which is one of the main seismogenic sources of the Iberian Peninsula. We deduce a fault slip rate of ∼1.3 ± 0.3 mm/yr for the whole Granada Basin, with 0.9 ± 0.3 mm/yr being accommodated in the Granada Fault System and 0.4 ± 0.3 mm/yr being accommodated in the southwestern sector of the Granada Basin, where no active faults have been previously described at the surface. The heterogeneous extension in the Central Betic Cordillera could be accommodated by shallow high‐angle normal faults that merge with a detachment at depth. Part of the active extension could be derived from gravitational instability because of underlying over‐thickened crust.

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Seismicity in Strike‐Slip Foreland Faults (Central Betic Cordillera Front): Evidence of Indentation Tectonics

Cited by 6 publications

References 67 publications

The Role of Faults as Barriers in Confined Seismic Sequences: 2021 Seismicity in the Granada Basin (Betic Cordillera)

The Role of Faults as Barriers in Confined Seismic Sequences: 2021 Seismicity in the Granada Basin (Betic Cordillera)

The Campo de Dalias GNSS Network Unveils the Interaction between Roll-Back and Indentation Tectonics in the Gibraltar Arc

Insights of Active Extension Within a Collisional Orogen From GNSS (Central Betic Cordillera, S Spain)

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