The Lingwu depression,located in the southeastern part of the Yinchuan Faulted Basin,has a complex geological tectonic framework and serves as the turning and intersection part of structures due to the two Himalayan tectonic stresses,namely the EW-direction tensile stress of the Ordos block and the NE-direction compressive stress of the Qinghai-Tibet Plateau. Since 1970, more than 3000 earthquakes with magnitudes of greater than 2.0 have been monitored in the Yinchuan Basin and its periphery. Among them, most of the small and moderately strong earthquakes occurred in the Lingwu depression, which, therefore, has serious hidden risks of earthquake disasters. Previous studies indicate that fault structures are the cause for the earthquakes and that strata serve as the main reason for the earthquake secondary disasters in this depression. To interpret the geological structures in the basement of the Lingwu depression, this study finely characterized the basement characteristics of the Lingwu depression using the 2.5D human-computer interactive inversion technology based on the 1∶50,000 regional gravity data and the constraints of data on drill holes, seismic profiles, magnetotelluric sounding, and controlled source audio-frequency magnetotellurics (CSAMT) profiles, thus providing a basis for the prevention and control of earthquake disasters.
Lei Q Y. The extension of the arc tectonic belt in the northeastern margin of the Tibet Plateau and the evolution of the Yinchuan basin in the western margin of the north China[D]. Beijing: China Academic Journal Electronic Publishing House, 2016.
李清河. 鄂尔多斯西缘与西南缘深部结构与构造[M]. 北京: 地震出版社, 1999.
Li Q H. Deep structure in the western and southwestern margins of Ordos[M]. Beijing: Seismological Publishing House, 1999.
Li Y, Liu B J, Feng S Y, et al. Exploration of shallow structure and buried faults in the Yinchuan basin using seismic refraction and reflection data[J]. Chinese Journal of Geophysics, 2017, 60(8):3096-3109.