The research of deep structural features of Weihe basin and adjacent areas

The crustal structure was investigated with Deep Seismic Sounding (DSS) data obtained from wide angle reflection/refraction profiles crossing the region; its southern section is Qin-ling fold zone, the middle is Weihe rift basin, and the northern section is the southern margin of the Ordos platform. The results showed that the crust has obviously layered and laterally varying structures; the boundary between upper and lower crust is reliably determined by the relatively continuous reflection wave, P2 and P3 in the crust. The M interface of Ordos platform is the deepest in the region; the crustal thickness is up to 42 km or so and the crustal structure is relatively simple with shallow crystalline basement. The crustal thickness of Qinling Fold Belt is about 37 similar to 38 km, with shallow or even exposed crystalline basement. The Moho interface under Weihe fault basin is significantly and asymmetrically uplifted relative to both sides, and the crustal structure is complex; the abrupt Moho uplift relative to the Ordos block and the intrusion of high-speed material of the upper mantle into the lower crust are the deep tectonic background of occurrence of strong earthquakes in the area.