Abstract:

Controlled sourse audiofrequency magnetolelluric(CSAMT) is an effective geophysical method for deep resource prospecting. The accuracy of most current instruments functioning in time-sharing measurement mode is easily affected by differences of various arrangement observation condition. In order to improve the efficiency and accuracy, a distributed electromagnetic system was developed which achieves multi-point observation simultaneously in a survey line. The system consists of an electromagnetic receiver array and a high power transmitter base on series technology and it can be used for the CSAMT and induced polarization method by moving emission source location. Inversion parameters are extracted from the original multi-channel data after interference suppression. The system was applied to deep groundwater prospecting in Songjianghe area, Jilin Province. The results which were compared with GDP32II shows that multi-point simultaneous measurement not only improve efficiency, but also overcome the horizontal abnormal impact generated by time-varying and regional noise. The potential location of deep groundwater was successfully predicted according to the exploration results and it had been verified by drilling.

Key words: electromagnetic prospecting, controlled sourse audio-frequency magnetolelluric, distributed system, simultaneous measurement, deep groundwater prospecting