Patent ID: 8873334

Claim:
A method for surveying, comprising: receiving, by a processor, first survey data from a first source, the first source comprising a first signal generated by a subsurface earth formation in response to a passive-source electromagnetic signal, wherein the electromagnetic signal is generated by an electroseismic or seismoelectric conversion of the passive-source electromagnetic signal; receiving, by the processor, second survey data from a second source; and processing the first survey data and the second survey data to determine one or more properties of a subsurface earth formation; and wherein the passive-source electromagnetic signal includes the earth's natural electromagnetic field and wherein the processing the first survey data and the second survey data to determine the one or more properties of the subsurface formation is based, at least in part, on a correlation of the earth's electromagnetic field and the electromagnetic signal generated by the electroseismic or seismoelectric conversion of the earth's natural electromagnetic field.