Abstract: A system for surveying a subsurface formation includes one or more electromagnetic sensors located at or above the surface of the Earth. The sensors are configured to detect passive-source source signals and return signals that are based on seismoelectric or electroseismic conversion of the source signal in the subsurface formation. The system includes a processor communicatively coupled to the one more electromagnetic sensors. The at least one processor is configured to align and stack the passive-source source signals and the return signals and determine a property of the subsurface formation based, at least in part, on the aligned and stacked passive-source source signals and the return signals.

Abstract: A system and method are provided for communicating in a borehole. In one example, the method includes receiving a baseband signal transmitted through a drill string using a plurality of elastic waves, where a spectrum of the baseband signal is duplicated after transmission due to oversampling. At least one passband is selected in order to recover the baseband signal from the duplicated spectrum. The baseband signal is decoded to recover a bit stream contained within the baseband signal.

Abstract: A system and method are provided for communicating in a borehole. In one example, the method includes receiving a baseband signal transmitted through a drill string using a plurality of elastic waves, where a spectrum of the baseband signal is duplicated after transmission due to oversampling. At least one passband is selected in order to recover the baseband signal from the duplicated spectrum. The baseband signal is decoded to recover a bit stream contained within the baseband signal.