Seismo-tectonics of Greater Iberia: An updated review

Abstract. From the analysis of 542 moment tensor focal mechanisms in Iberia, active tectonic deformations and stresses were inferred by implementing different and complementary methodologies: FMC classification of the rupture type; composed focal mechanism based on the average seismic moment tensor; rotation angle between tensors estimates; Right Dihedra composed focal mechanisms; Slip Model analysis to determine the strain conditions and classical stress inversion methodology. By using the Slip Model results and considering the tectonic constraints of the Cenozoic deformation in Iberia, the study region was subdivided into a series of zones where the different methods were individually applied. The results indicate that thrust faulting stress regimes are active in the Gorringe-Horseshoe area and the easternmost Tell Atlas. In the south, most of the zones are transpressive, as well as in the southwestern corner of Iberia, south of Lisbon. The exception is the Granada Basin, which displays an almost radial normal faulting stress regime. Normal faulting stresses are dominant in the Pyrenees and in the Mediterranean rim, north of the Betics. In the central part of the Pyrenees, we find a maximum horizontal extension perpendicular to the range, indicating that local stresses related to post-orogenic collapse or isostatic rebound dominate over regional ones. The maximum horizontal compression along the Eurasia-Africa plate limit is very homogeneously close to N154° E, except in some parts of the Betics that are probably influenced by a remanent effect of the Alboran Slab. In the Central Ranges and offshore Atlantic, the maximum horizontal compression is slightly rotated anticlockwise to N140° E.