Acomodación de la convergencia entre África y la Península Ibérica, Golfo de Cádiz y Mar de Alborán, a partir del análisis de terremotos

Abstract

The accommodation of the Africa-Eurasia convergence in the southern margin of the Iberian Peninsula can be described by the analysis of earthquakes distribution and magnitude. This analysis allows the differentiation of two segments in the plate boundary. In the Gulf of Cadiz, deep and high magnitude seismic events are localised under some submarine highs (Josephine, Gorringe, Sao Vicente and Guadalquivir) suggesting the existence of underthrusting zones connected by transfer transverse zones. The shallow and diffuse seismicity of this oceanic area would correspond to distributed deformation taken by shallow faults and related to the underthrusting of the Eurasian lithosphere. In contrast, the accomodation of the' convergence in the Alboran Sea is assumed in a zone of limited subduction, the West Alboran Subduction Zone, which is defined by the occurrence of intermediate earthquakes. In this zone, the Iberian lithosphere plunges under the weak Alboran platelet. The shallow, weak and diffuse seismicity corresponds indeed to distributed deformation. The main shocks of this segment are concentrated at depth in the contact between the strong African lithosphere and the Alboran platelet