The Spanish Central System is a Cenozoic pop-up with an E W to NE SW orientation that affects an the crust (thick-skinned tectonics). It shows antifonn geometry in the upper crust with thickening in the lower crust. Together -with the Iberian Chain it constitutes the most prominent mmmtainous structure of the Pyrenean foreland.The evolutionary patterns concerning the paleotopography of the interior of the Peninsula can be established by an analysis of the fo11owing data: gravimetric, topographical, macro and micro tectonic, sedimentological (infilling of the sedimentary basins of the relative foreland), P T t path from apatite fission tracks, paleoseismic and instrumental seismicity.Deformation is dearly asymmetric in the Central System as evidenced by the existence of an unique, large (crustal-scale) thrust at its southern border, while in the northern one there is a normal sequence of north verging thrusts, towards the Duero Basin, whose activity ended during the Lower Miocene. This deformation was accomplished lUlder triaxial compression, Oligocene Lower Miocene in age, marked by NW SE to NNW SSE shortening. Loca11y orientations of paleostresses deviate from that of the regional tensor, follo-wing a period of relative tectonic quiescence. During the Upper Miocene Pliocene, a reactivation of constrictive stress occurred and some structures underwent rejuvenation as a consequence of the action of tectonic stresses similar to those of today (lUliaxial extension to strike slip -with NW SE shortening direction). However, the westernmost areas show continuous activity throughout the whole of the Tertiary, with no apparent pulses. At the present time there is a moderate seismic activity in the Central System related to faults that were active during the Cenozoic, with the same kinematic characteristics.

Reflection profiles characterize the structure and the upper Mesozoic to Cenozoic deposits of the Gulf of Ciidiz region. Two long ENE-WSW multichannel seismic lines (ca. 400-500 km long) are analyzed to study the evolution of the area from the continental shelf to the Horseshoe and Seine abyssal plains. The huge allochthonous deposits emplaced in this region (the so called "Olistostrome" of the Gulf of Cadiz) are described in terms of three different domains on the basis of the seismic architecture, the main tectonic features and the nature of the basement, oceanic or continental. The eastern domain extends along the continental shelf and upper and middle slope and corresponds to the offshore extension of the Betic -Rifean external front. It is characterized by salt and shale nappes later affected by extensional collapses. The central domain develops along the lower slope between the Betic-Rifean front and the abyssal plains and is characterized by a change in dip of the allochthonous basal surface and the basement. The allochthonous masses were emplaced by a combined gravitational and tectonic mechanism.The nOlihern boundary of this domain is marked by the occurrence of an outstanding WNW -ESE-trending thrust fault with a strike-slip component, termed here as the Gorringe-Horseshoe fault. The westernmost domain corresponds to the abyssal plains, where the distal emplacement of the allochthonous body takes place; it is characterized by thrust faults affecting both the sedimentary cover and the oceanic basement. The allochthonous masses show a less chaotic character and the thickness decreases notably. These domains represent different evolutionary steps in the mechanisms of emplacement of the allochthonous units. The eastern domain of the allochthonous units was emplaced as part of the pre-Messinian orogenic wedge related to the collision that gave rise to the Betic-Rifean Belt, whereas the allochthonous wedge of the central and western domains were emplaced later as a consequence of the NE-SW late Miocene compression that continues in present times.

[1] Integration of stress indicator data, gravity data, crustal kinematics data, and analysis of topography and recent vertical motions demonstrates the occurrence of consistently oriented spatial patterns of large-scale Alpine to recent intraplate deformation in Iberia. The inferred upper crustal and lithospheric deformation patterns and the timing of the associated expressions at or near the surface support the existence of a close coupling with plate boundary processes operating at the margins of Iberia. Patterns of lithosphere and upper crustal folds are oriented perpendicular to the main axis of present-day intraplate compression in Iberia inferred from structural analysis of stress indicator data and focal mechanism solutions. These findings suggest the presence of lithospheric folds, with wavelengths compatible with theoretical predictions of folding wavelengths of Variscan lithosphere. Stress-induced intraplate deformation set up by plate interactions is compatible with indications for the absence of present-day deep mantle-lithosphere interactions inferred from seismic tomography.

The Iberian microcontinent and its connected oceanic crust are affected by deformations related to the Eurasian‐African plate boundary. Active stress inversions from populations of moment tensor focal mechanisms have been performed around and inside the Iberian peninsula, using a total of 213 moment tensor estimates. Main results are as follows: (1) The tensorial solutions show better consistency and lower misfits compared to those obtained previously from first P arrival focal mechanisms. (2) Along the Eurasia‐Africa western boundary, the type of active stresses progressively changes easternward from triaxial extension to uniaxial compression along the Terceira Ridge, the Gloria Fault zone, and the Gulf of Cadiz. (3) In the Betics‐Alboran‐Rif zone, uniaxial extension predominates with Shmax N155°E trending. (4) In northern Algeria, uniaxial compression reappears. (5) The Iberian foreland is currently under strike‐slip to uniaxial extension tensorial conditions.

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