TitleActive deformation in old oceanic lithosphere and significance for earthquake hazard: Seismic imaging of the Coral Patch Ridge area and neighboring abyssal plains (SW Iberian Margin)
Publication TypeJournal Article
Year of Publication2013
AuthorsMartínez-Loriente S, Grácia E, Bartolomé R, Sallares V, Connors C, Perea H, Iacono CLo, Klaeschen D, Terrinha P, Dañobeitia JJosé, Zitellini N
JournalGeochemistry, Geophysics, Geosystems
Date Publishedjul
Keywordsblind thrusts, fault-bend folds, Iberia-Africa boundary, multichannel seismics, seismic hazard assessment, strike-slip faults
AbstractRecently acquired high-resolution multichannel seismic profiles together with bathymetric and sub-bottom profiler data from the external part of the Gulf of Cadiz (Iberia-Africa plate boundary) reveal active deformation involving old (Mesozoic) oceanic lithosphere. This area is located 180 km offshore the SW Iberian Peninsula and embraces the prominent NE-SW trending Coral Patch Ridge, and part of the surrounding deep Horseshoe and Seine abyssal plains. E-W trending dextral strike-slip faults showing surface deformation of flower-like structures predominate in the Horseshoe Abyssal Plain, whereas NE-SW trending compressive structures prevail in the Coral Patch Ridge and Seine Hills. Although the Coral Patch Ridge region is characterized by subdued seismic activity, the area is not free from seismic hazard. Most of the newly mapped faults correspond to active blind thrusts and strike-slip faults that are able to generate large magnitude earthquakes (Mw 7.2-8.4). This may represent a significant earthquake and tsunami hazard that has been overlooked so far. Key Points New active structures have been mapped in the Coral Patch Ridge area The newly mapped faults are able to generate large magnitude earthquakes (Mw>7) These new structures may represent a significant earthquake and tsunami hazard ©2013. American Geophysical Union. All Rights Reserved.