![]() ![]() We present field geological, structural, and geomorphological data collected in central El Salvador that allow the constraint of the kinematics and the Quaternary activity of this major seismogenic strike-slip fault system. Focal mechanisms and the distribution of the most destructive earthquakes, together with geomorphologic evidence, suggest that this transcurrent component of motion may be accommodated by a major strike-slip fault (El Salvador fault zone). Several major earthquakes have affected El Salvador, Central America, during the Past 100 yr as a consequence of oblique subduction of the Cocos plate under the Caribbean plate, which is partitioned between trench-orthogonal compression and strike-slip deformation parallel to the volcanic arc. The lithospheric feedback model suggests that strike-slip fault zones are not mechanically stratified in terms of shear stress, and that it is the time-dependent interaction of the different lithospheric layers - rather than their relative strengths - that governs the rheological behavior of the plate boundary, strike-slip fault zones.Īctive strike-slip faulting in El Salvador, Central AmericaĬorti, Giacomo Carminati, Eugenio Mazzarini, Francesco Oziel Garcia, Marvyn Low mantle viscosity within the shear zone is critical for facilitating mantle flow, which induces widespread crustal deformation and displacement loading. Such forced localization leads to higher stresses and strain rates in the shear zone compared to the surrounding rocks. Fault rupture in the upper crust induces displacement rate loading of the upper mantle, which in turn, causes strain localization in the mantle shear zone beneath the strike-slip fault. Systems support the prediction for constant shear strength (Ëœ10 MPa) throughout the lithosphere the stress magnitude is controlled by the shear strength of the upper crustal faults. Rheological structure of the lithosphere in plate boundary strike-slip fault zonesĬhatzaras, Vasileios Tikoff, Basil Kruckenberg, Seth C. Two nearly perpendicular strike-slip tectonic regimes are recognized in the NFS an inactive E-W Late Cretaceous - Early Cenozoic dextral transpression and an active NNE sinistral shear. The NNE sinistral faults extend for long distances ranging from 30 to 100 kms and cut one or two E-W PDZs. ![]() The NNE faults consist of right-stepping sinistral strike-slip fault segments (e.g. Several multi-scale uplifts and basins were developed at the step-over zones between parallel strike-slip fault segments as a result of local extension or contraction. Each fault zone has typical self-similar strike-slip architecture comprising multi-scale fault segments. Each PDZ is defined by spectacular E-W, WNW and ENE dextral strike-slip faults, NNE sinistral strike-slip faults, NE to ENE folds, and NNW normal faults. The NFS consists of several E-W Principal Deformation Zones (PDZs) (e.g. Structural setting and kinematics of Nubian fault system, SE Western Desert, Egypt: An example of multi-reactivated intraplate strike-slip faultsĭetailed surface geological mapping and subsurface seismic interpretation have been integrated to unravel the structural style and kinematic history of the Nubian Fault System (NFS). ![]()
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