Use of Audio-Band in the Interpretation of Magnetotelluric Data

We propose a new efficient method for acquiring the audio-frequency magnetotelluric (AMT) data during the magnetotelluric (MT) survey and discuss about the usage of the AMT data. Comparison of the two-dimensional inversion model using MT band only and that using both AMT and MT bands said that high frequency information is useful especially when resistivity structures at shallow depths vary rapidly with depth. AMT data in MT interpretation will also be useful when the formation is so resistive that the skin depth at highest frequency of MT band readily reaches to a few hundred meters as in case of Korea.