@article {Manchuel2011, title = {{New insights on the interseismic active deformation along the North Ecuadorian-South Colombian (NESC) margin}}, journal = {Tectonics}, volume = {30}, number = {4}, year = {2011}, month = {aug}, pages = {n/a{\textendash}n/a}, abstract = {The North Ecuadorian-South Colombian subduction zone was the site of the 1906 Mw 8.8 megathrust earthquake. This main shock was followed by three large events in 1942, 1958, and 1979 whose rupture zones were located within the 500 km long 1906 rupture area. A combined onshore and offshore temporary seismic network covering from the trench to the Andes was deployed during 3 months in the area of large earthquakes, in order to obtain a detailed knowledge of the seismic background activity. Resulting earthquakes location and mechanisms bring new insights on interseismic active deformation distribution in the three main tectonic units of the margin, namely, the Interplate Seismogenic Zone, the fore-arc region which is part of the North Andean Block and the downgoing oceanic Nazca plate. The interplate seismic activity presents along strike variations, suggesting that the seismicity and the associated stress buildup along the plate interface depend on the time elapsed since the last large earthquakes. According to our results, the updip and downdip limits of the seismogenic zone appear to be located at 12 and 30 km depth, respectively. Shallow to intermediate depth seismicity indicates a slab dip angle of ≈25{\textdegree}. North of the Carnegie Ridge, the Wadati-Benioff plane is defined beneath the fore arc down to ≈100 km depth. Facing the ridge, the Wadati-Benioff plane extends beneath the Andes, down to ≈140 km depth. This observation conflicts with the hypothesis of the presence of a flat slab at a depth of 100 km facing the ridge. In the overlying fore-arc region, the crustal seismicity occurs down to 40 km depth and is mainly concentrated in a roughly NW-SE 100 km wide stripe stretching from the coast, at about 1{\textdegree}N, to the Andes. The location of this active deformation stripe coincides with observed tectonic segmentation of the coastal domain as evidenced by the presence of an uplifting segment to the south and a subsiding segment to the north of the stripe. It also corresponds to a ≈30{\textdegree} change in the trend of the Andes, suggesting that the curvature of the volcanic arc might play an important role in the deformation of the fore-arc region. Copyright 2011 by the American Geophysical Union.}, issn = {02787407}, doi = {10.1029/2010TC002757}, url = {http://doi.wiley.com/10.1029/2010TC002757 http://www.scopus.com/inward/record.url?eid=2-s2.0-79960929640\&partnerID=tZOtx3y1}, author = {Manchuel, Kevin and R{\'e}gnier, Marc and B{\'e}thoux, Nicole and Font, Yvonne and Sallares, Valenti and D{\'\i}az, Jordi and Yepes, Hugo} } @article {Sallares2011, title = {{Seismic evidence for the presence of Jurassic oceanic crust in the central Gulf of Cadiz (SW Iberian margin)}}, journal = {Earth and Planetary Science Letters}, volume = {311}, number = {1-2}, year = {2011}, month = {nov}, pages = {112{\textendash}123}, abstract = {We investigate the crustal structure of the SW Iberian margin along a 340. km-long refraction and wide-angle reflection seismic profile crossing from the central Gulf of Cadiz to the Variscan continental margin in the Algarve, Southern Portugal. The seismic velocity and crustal geometry model obtained by joint refraction and reflection travel-time inversion reveal three distinct crustal domains: the 28-30. km-thick Variscan crust in the north, a 60. km-wide transition zone offshore, where the crust abruptly thins \~{}. 20. km, and finally a \~{}. 7. km-thick and \~{}. 150. km-wide crustal section that appears to be oceanic in nature. The oceanic crust is overlain by a 1-3. km-thick section of Mesozoic to Eocene sediments, with an additional 3-4. km of low-velocity, unconsolidated sediments on top belonging to the Miocene age, Gulf of Cadiz imbricated wedge. The sharp transition between continental and oceanic crust is best explained by an initial rifting setting as a transform margin during the Early Jurassic that followed the continental break-up in the Central Atlantic. The narrow oceanic basin would have formed during an oblique rifting and seafloor spreading episode between Iberia and Africa that started shortly thereafter (Bajocian) and lasted up to the initiation of oceanic spreading in the North Atlantic at the Tithonian (late Jurassic-earliest Cretaceous). The velocity model displays four wide, prominent, south-dipping low-velocity anomalies, which seem to be related with the presence of crustal-scale faults previously identified in the area, some of which could well be extensional faults generated during this rifting episode. We propose that this oceanic plate segment is the last remnant of an oceanic corridor that once connected the Alpine-Tethys with the Atlantic ocean, so it is, in turn, one of the oldest oceanic crustal fragments currently preserved on Earth. The presence of oceanic crust in the central Gulf of Cadiz is consistent with geodynamic models suggesting the existence of a narrow, westward retreating oceanic slab beneath the Gibraltar arc-Alboran basin system. {\textcopyright} 2011 Elsevier B.V.}, keywords = {Geodynamic evolution, Jurassic oceanic crust, Refraction and reflection travel-time tomography, SW Iberian margin, Uncertainty analysis, wide-angle seismics}, issn = {0012821X}, doi = {10.1016/j.epsl.2011.09.003}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-81155155560\&partnerID=tZOtx3y1}, author = {Sallares, Valenti and Gailler, Audrey and Gutscher, Marc-Andr{\'e} and Graindorge, David and Bartolom{\'e}, Rafael and Gr{\'a}cia, Eul{\`a}lia and D{\'\i}az, Jordi and Da{\~n}obeitia, Juan Jos{\'e} and Zitellini, Nevio} }