Zonación sismotectónica del NO de la Península Ibérica

Abstract

The northwestern part of the Iberian Peninsula shows a permanent seismicity of low to moderate magnitude within the seismotectonic context of the Euro-Mediterranean region. However, a significant increase of seismic activity has taken place since 1995. Several crises have occurred in Lugo province, with a main earthquake of magnitude 5.3 in 1997. A detailed study of the local seismicity was undertaken between 1999 and 2002, based on the deployment of a temporary network. More than 500 local earthquakes were recorded, with epicentres scattered irregularly over the NW Iberian Peninsula, including the continental platform. The highest concentration of events is located onshore the Atlantic margin, in the southern and eastern part of Galicia, decreasing progressively eastwards. The characterization of this recent activity in relation with the different identified tectonic provinces has allowed to establish a new seismotectonic zonation of the northwestern region. Our results allow to differentiate five main seismotectonic domains with similar structural characteristics and a homogenous seismic behavior. This zonation supposes an advance in the regional seismotectonic knowledge and constitutes the basic document for future seismic hazard estimation in this area.