Patent ID: 6950747

Claim:
A method of processing magnetotelluric signals to identify subterranean deposits, said method comprising: (a) obtaining magnetotelluric data from an area of interest, said magnetotelluric data comprising the amplitude of magnetotelluric signals recorded over time at one or more defined locations in said area of interest; (b) filtering said magnetotelluric data for each said location at a set of predetermined frequencies to separate the amplitude data at said frequencies from the remainder of said amplitude data for said locations, wherein said frequencies correspond to subterranean depths over a range of interest; (c) identifying the amplitude peaks in said filtered amplitude data; and (d) analyzing said amplitude peaks to determine a value correlated to the resistance of the earth at each said frequency at each said location; the resistance being indicative of the presence or absence of deposits at the corresponding subterranean depth.