| Summary: | Major structures of the Sinu and San Jacinto Deformation Belts (SSJDB)characterize the area and are represented by anticline and synclinal folds, NE-SW high angle thrust-faults, NW-SE left-lateral strike-slip faults and E-Wright-lateral strike-slip faults. Locally, there are diapiric features like mud volcanoes, sometimes associated to gas/oil seeps, previously attributed to fold structures orthogonal to regional compression based on geophysical data. In this case study, we identified a close relationship between diapiric features and morphostructural lineaments on the land area as well as on the continental shelf, mainly denoted by E-W and WNW-ESE direction structures. Seismic information also allowed the identification of a relationship between the lower mud level underlying the tertiary sedimentary sequence and pliocene-pleistocene diapiric features. The inversion stress analysis indicates that the E-W / NW-SE structures are related to a WNW-ESE regional compressional stress, so implying that the E-W structures are right-lateral strike-slip faults and the NW-SE structures are reactivated left-lateral strike-slip faults. In both cases, a normal component was detected and that suggests a transtractive character to these structures. The presence of mud volcanoes indicates that the lower mud levels submitted to overpressurization help to generate or/and reactivate secondary fractures and faults associated to the NW compression related to the E-Wdextral transcurrent binary. The E-W and WNW-ESE dextral transcurrent faults and the NW-SE sinistral transcurrent faults, which control the mud diapirism, act as fluid-conducting surfaces - or leaky faults - that must be taken into account on the studies aiming the characterization of hydrocarbon migration processes in the SSJDB.
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