Crustal deformation in eastern Betics from CuaTeNeo GPS network

Abstract

The eastern Betic Cordillera, Spain, is the most seismically active area within the Iberian Peninsula. We present a Global Positioning System (GPS)-derived horizontal crustal deformation obtained from five occupations of the CuaTeNeo GPS network (1997, 2002, 2006, 2009 and 2011) that clearly shows continuing tectonic activity in the SE Betics. The most prominent feature of the GPS velocity field is the NW oriented motion of the majority of the stations at rates ranging from 2 mm/yr near the coast to 0.5 mm/yr inland. This type of deformation indicates that the main driving force responsible for the observed velocities is related to the on-going convergence between Nubia and Eurasia plates. The calculated deformation field shows evidence for localized deformation related to active faults within the area. Most of the deformation is concentrated on the Alhama de Murcia fault, the source of the 2011 Lorca earthquake (Mw 5.2). We estimate a reverse-sinistral geodetic slip rate of 1.5 ± 0.3 mm/yr for this fault. Our crustal deformation field and analyses are important contributions to estimating seismic hazard for the eastern Betics, since it is the first time crustal deformation rates at this scale are presented.