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The structure of the Alboran Sea: an interpretation from seismological and geological data

2001; Elsevier BV; Volume: 338; Issue: 2 Linguagem: Inglês

10.1016/s0040-1951(01)00059-2

1879-3266

Carlos López Casado, C. Sanz de Galdeano, Sergio Molina, Jesús Henares,

Geological and Geochemical Analysis

Almost all the earthquakes included in the catalog for the Iberian–Maghrebian area up to 2000 have been used in order to know the structure of the Alboran Sea area after the verification of the aleatory nature of the errors in their spatial localization. A new focal mechanisms catalog has also been used as well as many of the available geological data. During the Mesozoic and till the Oligocene, the Betic–Rif Internal Zone was situated further E, but with the opening of the Algero-Provençal basin in the early Miocene, the Betic–Rif Internal Zone moved to the W. Contemporary, the Alboran Sea was created as the western prolongation of the Algero-Provençal basin. The Betic–Rif Internal Zone overthrused part of the Iberian and African plates, producing the partial sinking of both plates and being responsible of the intermediate seismicity existing in the western sector of the Alboran Sea. The intermediate earthquakes in the Atlas towards the NE and WSW are not related to lithospheric sinking but to significant deep faults limiting a subplate in NW Africa. In the Atlantic, the intermediate earthquakes between the Gorringe sector and Gibraltar are produced in the contact between the Iberian and African plates and by the important faults crossing it. The existence of four very deep earthquakes is related to the previous sinking of the lithosphere originally associated to the domain in which the Betic–Rif Internal Zone was situated.