Hydrogeological prospecting in the Da Qaidam area of the Qaidam Basin using the audio-frequency magnetotelluric method

The Qaidam Basin has very little precipitation but large surface evaporation. Besides, the groundwater resources are unevenly distributed, which gradually decrease from east to west. Therefore, reasonable exploration and management of the groundwater resources are very important in this area. This study performs a hydrogeological survey in this area using the audio-frequency magnetotelluric method (AMT). We establish a priori model using the hydrogeological records and geophysical data. Then, 226 AMT sites are arranged to collect data. Using the three-dimensional (3-D) inversion technology, we obtain a reliable electrical structure of the underground area within 3000 m deep of the Qaidam Basin. On the basis of the 3-D inversion results and the priori model, we analyze the distribution and features of the underground aquifers and investigate the hydrological characteristics, including the quaternary strata, aquifers, paleochannels, deep geological structure and groundwater migration characteristics. This research may provide scientific references for the underground water exploration and management in the Da Qaidam area. •The Qinghai Tibet Plateau is a hot spot area of geophysical research.•We analyze the regional rock physical properties and obtain reliable prior information and electrical basis.•We obtain the distribution and features of the underground aquifers and investigate the hydrological characteristics.•The distribution of paleochannels in Da Qaidam is investigated.