Active faults, seismicity and stresses in an internal boundary of a tectonic arc (Campo de Dalías and Níjar, southeastern Betic Cordilleras, Spain)

The maximum horizontal compression has a consistently NNW-SSE trend. The deep activity of detachments and reverse faults determines the NNW-SSE crustal shortening related to the Eurasian-African plate convergence. At surface, however, the predominance of normal faults is probably produced by the increase in the relative weight of the vertical stress axis, which in turn may be related to relief uplift and subsequent horizontal spreading. The internal mountain front boundary of the Betic Cordilleras developed through the activity of a set of structures that is more complex than a typical external mountain front, probably as a consequence of a vertical variable stress field that acted on previously deformed rocks belonging to the Internal Zone of the cordilleras.