Abstract
The Portuguese western continental margin is divided into two distinct parts by the Nazaré submarine valley (Nazaré canyon). Some faults of the most important system of faults in Mainland Portugal, which do not show significant seismic activity on land, show remarkable activity when they penetrate into the continental margin, along submarine valleys, probably due to infiltration of the sea water and corresponding lubrication of the fault plane. The seismicity of the Portuguese southern continental margin is dominated by the activity of the compressional section of the Azores-Gibraltar fault. Focal mechanism solutions in the whole area are consistent with a uniform seismic stress field in agreement with that which is expected from the collision of the Eurasian and African plates. It is assumed that the present-day seismicity of the region is governed by the stress field originated by that collision. An increase of the seismic activity in the Iberian abyssal plain, approximately along 15 W meridian, suggests correlation with the Tore seamount and some guyots that exist in that area.
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Moreira, V.S. (1989). Seismicity of the Portuguese Continental Margin. In: Earthquakes at North-Atlantic Passive Margins: Neotectonics and Postglacial Rebound. NATO ASI Series, vol 266. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-2311-9_31
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DOI: https://doi.org/10.1007/978-94-009-2311-9_31
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