Departamento de Ingeniería Cartográfica, Geodésica y Fotogrametría
URI permanente para esta comunidadhttps://hdl.handle.net/10953/36
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Examinando Departamento de Ingeniería Cartográfica, Geodésica y Fotogrametría por Autor "Alfaro, Pedro"
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Ítem How Much Nubia‐Eurasia Convergence Is Accommodated by the NE End of the Eastern Betic Shear Zone (SE Spain)? Constraints From GPS Velocities(American Geophysical Union, 2019-04-29) Borque, María Jesús; Sánchez-Alzola, Alberto; Martín-Rojas, Iván; Alfaro, Pedro; Molina-Palacios, Sergio; Rosa-Cintas, Sergio; Rodríguez-Caderot, Gracia; de-Lacy, María Clara; García-Armenteros, Juan Antonio; Avilés-Moreno, Manuel; Herrera-Olmo, Antonio Manuel; García-Tortosa, Francisco Juan; Estévez-Rubio, Antonio; Gil-Cruz, Antonio JoséWe 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.Ítem The Campo de Dalias GNSS Network Unveils the Interaction between Roll-Back and Indentation Tectonics in the Gibraltar Arc(MDPI, 2022-03-09) Galindo, Jesús; Gil-Cruz, Antonio José; Tendero-Salmerón, Víctor; Borque, María Jesús; Ercilla, Gemma; González-Castillo, Lourdes; Sánchez-Alzola, Alberto; de-Lacy, María Clara ; Estrada, Ferran; Avilés-Moreno, Manuel; Alfaro, Pedro; Madarieta-Txurruka, Asier; Chacón, FernandoThe 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, the 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.