A method for processing magnetotelluric signals to identify subterranean deposits is provided for. The methods comprise obtaining magnetotelluric data from an area of interest. The magnetotelluric data comprises the amplitude of magnetotelluric signals recorded over time at one or more defined locations in the area of interest. The data for each location then is filtered through a set of frequency filters. The frequency filters correspond to subterranean depths over a range of interest. Amplitude peaks in the filtered data then are identified and analyzed to determine a value correlated to the resistance of the earth at each frequency and location. The resistance values are indicative of the presence or absence of deposits at the corresponding subterranean depth. Preferably, the amplitude data is power normalized across all locations in the survey, a gain factor is applied to the resistance values to scale the values for depth variation, and the resistance values are displayed as a depth-location plot for interpretation.