Deep conductivity characteristics of the southern Xianshuihe fault zone

Based on research of measured data of the magnetotelluric and gravity-magnetic profile of Xinduqiao-Xiaojin, combined with regional geological data, the relationship between deep structure, crustal conductivity layer, electrical structure and historical earthquake of the southern section of the Xianshuihe fault zone and adjacent areas is studied. The results are shown as follows. First, the Xianshuihe fault zone shows different forms in deep and shallow parts. The shallow fault system is mainly a brittle shear zone in the crust and the deep fault system is mainly strike-slip ductile shear zones in the crust and mantle with a flower morphology and reaching the upper mantle in the deep part. Second, crustal conductivity layers are widely developed in the middle and lower crust of Danba tectonic belt and Xianshuihe fault zone, indicating inhomogeneity, related to the fault movement. Third, remelting of the upper crust may be the main mechanism of Zheduoshan granite. Fourth, the earthquake mechanism is controlled by the fault zone in the Xianshuihe fault zone and closely related to the weak layer as well. It is mainly controlled by shearing of strike-slip faults between plates in the shallow part. The stress is concentrated within the high resistance and brittle medium near the fault, where medium changes in the turning points, resulting rock breaking and earthquakes.