Abstract
In 2-D resistivity surveys, it is important to use the electrode array yielding the highest resolution and accuracy. Although a number of studies have been done to examine the characteristics of various electrode arrays, it is not well known how the electrode array affects the resolution and accuracy of 2-D inversion. In this paper, the relationship between the electrode arrays and the accuracy of 2-D resistivity surveys is analysed through numerical simulation. In addition, the performances of 2-D resistivity and CSAMT methods are compared. It is shown that if the data accuracy is about the same, the dipole-dipole array is superior to the pole-pole and pole-dipole arrays. However, if the signal level is considered, the pole-dipole array gives the best result. It is also shown that the synthesis of pole-dipole data from pole-pole data is effective in improving the accuracy of 2-D inversion if the original pole-pole data have an relative error of about 1%. Comparison of resistivity and CSAMT methods shows that CSAMT method may be superior to resistivity method in resolving vertically extending structures when the scale of exploration is relatively large. It is also expected that resistivity and CSAMT methods complement each other in defining the structures showing pseudo-anisotropy, such as fractured zones.
