Active rollback in the Gibraltar Arc: Evidences from CGPS data in the western Betic Cordillera

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

“…Deformation within the Alboran Sea is driven in part by the NW‐SE regional convergence of the Eurasian and African plates (de Mets et al, ). The west to west‐southwestward motion of the Betic‐Rif Alboran block (Koulali et al, ; Palano et al, ) may also be the result of ongoing slab rollback toward the west (González‐Castillo et al, ; Gutscher et al, ; Pedrera et al, ; Ruiz‐Constán et al, ; Spakman et al, ), which would explain the E‐W to ENE‐WSW extensional focal mechanisms observed in the West Alboran Sea (Stich et al, ). At present, the GEODVEL plate model (Argus et al, ) indicates a N141°E trend of convergence at a rate of 4.93 mm/yr in this region, supported by regional GPS data (Fadil et al, ).…”

“…The westward migration of the Gibraltar Arc is well constrained by geological (Crespo‐Blanc et al, ) and GPS data (Fadil et al, ; Koulali et al, ; Palano et al, ). However, the driving mechanism remains a matter of debate, with geodynamic models considering delamination (e.g., Lis Mancilla et al, ; Seber et al, ) and subduction (e.g., González‐Castillo et al, ; Gutscher et al, ; Pedrera et al, ; Ruiz‐Constán et al, ; Spakman et al, ), while rollback is a suitable mechanism for Gibraltar Arc westward displacement and Alboran Sea development. The growth of this seismic NNE‐SSW fault zone occurs in the area of weakest and most attenuated continental crust, corresponding to the central Alboran Sea, bounded by the thick continental crust of the Betic and Rif Cordilleras.…”

“…Several geodynamic models have been proposed for the region, including delamination (e.g., Lis Mancilla et al, ; Seber et al, ) or subduction with or without rollback (e.g., González‐Castillo et al, ; Gutscher et al, ; Pedrera et al, ; Ruiz‐Constán et al, ; Spakman et al, ), yet discussion remains alive. Moreover, in the central and eastern Alboran Sea, the recent fault system mainly composed by two conjugate WNW‐ESE dextral and NNE‐SSW sinistral fault sets evidences the activity of continental indentation tectonics (Estrada et al, ).…”

Tectonic indentation in the central Alboran Sea (westernmost Mediterranean)

“…During the Early Miocene, continental crustal thinning occurred (Vissers, Platt, & Wal, ), followed by a compressive period since the Late Tortonian (Sanz de Galdeano & Alfaro, ). Tectonic models for the recent evolution of the area support subduction activity (Doglioni, Gueguen, Harabaglia, & Mongelli, ; Doglioni, Gueguen, Sabat, & Fernandez, ; Gutscher et al., ; Morales et al., ; Ruiz‐Constán, Galindo‐Zaldívar, Pedrera, Celerier, & Marín‐Lechado, ) and possible roll‐back processes (Do Couto et al., ; Gonzalez‐Castillo et al., ; Zeck, ) or delamination (Docherty & Banda, ; de Lis Mancilla et al., ; Seber, Barazangi, Ibenbrahim, & Demnati, ). All the models hold that the internal zones of the Betic–Rif Cordillera move westward above the Africa–Eurasia plate boundary (Koulali et al., ; Palano, González, & Fernández, ).…”

answer to the referee 2

“…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.…”