P- and S-wave seismic tomography detect a low-velocity anomaly in the upper mantle beneath the Betic Cordillera and the Alboran Sea region. The anomaly is associated with the intermediate-depth seismicity (h < 110 km) in the region. This structure is interpreted as a result of an active continental subduction. Gravity modeling and seismic attenuation also show the continental nature of the low-velocity zone. Stresses determined from the focal mechanisms of the intermediate-depth earthquakes also agree with the scenario of continental subduction, which is caused by the middle-late Miocene to present-day northwest-southeast convergence of the African and European plates and the continental collision that raised the cordillera.
|Number of pages
|Published - 1999 Aug