2. Geological Exploration Technology Institute of Anhui Province，Hefei 230000，China

detection was carried out． The length of the profile is 15 km，and the observed data are the electric field amplitudes from two emitters． In this paper，the finite memory quasi Newton method is used for 3D inversion． In the inversion process，the staggered grid finite-difference technique taking into account the distribution characteristics

of field sources is used in forward modeling． The three-dimensional inversion model of observation data shows that the middle，southernmost and northernmost sections of the profile are characterized by high resistivity，while the two sides near the middle section are characterized by low resistivity． Moreover，the resistivity of the whole profile is characterized by the alternation of high and low resistances． Combined with the geological data，the resistivity change of 3D inversion reflects the widespread occurrence of Cretaceous，Late Devonian，Early Silurian and deep Ordovician strata in the study area． The results of this paper show the feasibility and necessity of 3D band source inversion with controllable source electric field amplitude |Ex| data of multi-source and single profile．

amplitude    Ex      Fanchang area