Cinemática de fallas y deformación con sistemas GNSS en la Cordillera Bética Oriental

Abstract

The eastern Betic Cordillera (CBO) is one of the most seismically active areas of the Iberian Peninsula, as it accommodates part of the convergence between the Eurasian and Nubian plates. This project analyses the eastern sector of the ZCBO and the area to the south of it. In particular, the horizontal velocity field was derived by the analysis of both, the newly collected and previously available, GNSS data. From these data, the relative displacement velocity vectors with respect to a fixed Eurasian plate (obtained from the ITRF2014 model) have been calculated. These results have made it possible to distinguish a present-day crustal deformation oriented predominantly in the direction of NNW-SSE to NNE-SSW. These velocities reach their maximum of 1-2 mm/year in the southern sector of the study area, while in the western and north-eastern part, movements of ≈1 mm/year are observed. The northern area is deforming significantly slower, with velocities slightly above 0 mm/year. In addition, the rates of shortening or extensional movement and lateral displacement have been calculated for the selected three faults. On the Las Moreras fault, a shortening rate of 0.2±0.2 mm/year and a differential dextral movement of 0.3±0.2 mm/year are calculated. In the Carrascoy fault, the same rate of 0.2±0.3 mm/year is obtained for shortening and sinistral displacement. With respect to the Crevillente fault, a shortening velocity of 0.3±0.3 mm/year and a sinistral displacement movement of 0.6±0.3 mm/year are estimated. Finally, the strain rates were calculated from the obtained velocities, indicating that the area is being subjected to a notable predominance of the shortening regime, oriented N-NW, roughly parallel to the Nubia/Eurasia convergence direction, which reaches a maximum value of εmin= -20±2 nstrain/year in the SW sector of the study area. Similar magnitude shear strain rates can be observed in the southern region, coinciding with ZCBO.