Stress fields in the Iberian-Maghrebi region
This study concerns the present stress field between the Eurasian and African plates in the Iberian-Maghrebi region (Portugal, Spain, Morocco, Algeria and Tunisia). In addition to an up-to-date catalogue of earthquakes in this area, a catalogue of the focal mechanisms composed of 486 solutions of fa...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2003 |
| País: | España |
| Institución: | Universidad de Jaén |
| Repositorio: | RUJA. Repositorio Institucional de la Producción Científica de la Universidad de Jaén |
| OAI Identifier: | oai:ruja.ujaen.es:10953/6959 |
| Acceso en línea: | https://doi.org/10.1023/A:1021294015027 https://hdl.handle.net/10953/6959 |
| Access Level: | acceso abierto |
| Palabra clave: | Betic Cordillera Iberian-Maghrebi region Focal mechanism Stress field 55 |
| Sumario: | This study concerns the present stress field between the Eurasian and African plates in the Iberian-Maghrebi region (Portugal, Spain, Morocco, Algeria and Tunisia). In addition to an up-to-date catalogue of earthquakes in this area, a catalogue of the focal mechanisms composed of 486 solutions of fault planes,standardized in terms of notation and information type, was used. These data were used applying the right-dihedron method of Angelier and Mechler (1977), to obtain different zones with homogeneous stress. The results obtained for shallow earthquakes (h < 30 km) coincide, in the majority of cases, with the general stress fields proposed by numerous authors for this region, according to which there is NW-SE compression. However, the stress orientation appears to vary in certain areas, perhaps perturbed by the opening of the Atlantic Ocean, the approach of Iberia and Africa, or the extension of the Alboran Sea. For the intermediate earthquakes (30 < h< 150 km) no general pattern was found,and the P and T axes seem to be randomly oriented for the depth intervals considered. For the very deep earthquakes(h > 600 km), however, the P axis lies in a NNW-SSE direction, dipping towards the SSE, while the T axis is subhorizontal in a NE-SW direction. The determinations from the focal mechanisms highlight the existence of a regional stress field with a subhorizontal compression axis trending NW-SE. Superimposed are others that specifically affect particular sectors; these are related to the opening of the Atlantic Ocean, the extension of the Betic Cordillera and the Alboran Sea, and even the present compression between the Iberian and European plates. |
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