Hazard in the Gulf of Cadiz: review of the large seismogenic structures

Abstract

The Gulf of Cadiz is located at the SW Iberian Margin and hosts the African-Eurasian plate boundary. This is one of the most seismogenic areas in Western Europe, where historical and instrumental earthquakes occurred, ranging from Mw 6 to 8.5, and some of them triggered destructive tsunamis. The ICM-CSIC team keeps investigating the Gulf of Cadiz area since more than 15 years, carrying out multiscale bathymetric, high-resolution to deep seismic and sampling surveys. The active structures in the Gulf of Cadiz can be classified in two main families: The WNW-ESE dextral strike-slip faults and the NE-SW thrusts faults. The orientation of these faults is compatible with the current plate convergence in the region. The largest active strike-slip faults are: -the Lineament South and the Lineament North that may generate earthquakes up to Mw 8; while the active NE-SW thrust faults, the Marquês de Pombal, the Horseshoe and the Coral Patch Ridge faults can individually generate earthquakes up to Mw7.8