Geoelectric methods have been widely used in the field of engineering and mineral exploration. Each method has its own advantage and disadvantage in interpreting depth and electrical properties of underlying subsurface. Combination of sounding data from various methods has been proved to be an effective way to improve reliability of interpretation as cited from many published literatures. Among them, several authors developed intriguing schemes to simultaneously invert two sounding data collected from two different surveying methods into a geoelectric section. These studies show that the interpreted sections based on joint-inversion scheme are superior to those from inversion of single data set alone.

This research is an extension of their work by inverting coincident loop transient electromagnetic (TEM) data, magnetotelluric (MT) data and Schlumberger sounding (DC) data simultaneously. An appropriate joint inversion scheme has been developed. Synthetic sounding data sets for DC, MT, and TEM based on a six-layer earth model were used to evaluate the performance of our scheme. Our study shows that the estimated model parameters from joint inversion of the triple data sets are more consistent with the hypothetical model than those derived by any inversion result using DC, TEM, or MT data alone. Furthermore, our result also indicates that our proposed scheme is superior to the joint inversion scheme based on DC and MT, DC and TEM, or TEM and MT.