Abstract

Recent improvements in regional seismological networks allow a better definition of the seismicity and the determination of focal mechanisms in south Spain. This region is part of the lithospheric plate boundary between Africa and Eurasia and shows a continuous seismic activity of moderate magnitude (M < 5) and the occurrence of large earthquakes separated by long time intervals. The distribution of epicenters for the period 1965 to 1985 shows that earthquakes are located south of the Cádiz-Alicante fault and that they can be associated with observed geological faults. An important activity at intermediate depth (30 km < h < 150 km) is located between Granada and Málaga and is separated from the very deep (h ≈ 650 km) earthquakes also occurring in the region. Eight fault-plane solutions have been determined that can be related to the tectonics of the area. The solutions for the shallow shocks are compatible with regional stresses with horizontal compressions in NW-SE direction and tensions in E-W direction that produce normal faulting along the N30° to 60°W and N10° to 30°E systems of faults. The mechanisms of the intermediate depth shocks can be explained in terms of a subduction zone from Africa in a NW direction that is under compression.

First Page Preview

First page PDF preview
You do not currently have access to this article.