| 摘要 |
A method for seismic surveying includes disposing a plurality of seismic sensors in a selected pattern above an area of the Earth's subsurface. A seismic energy source is repeatedly actuated proximate the seismic sensors. A signal used to actuate the source comprises a linear chirp having a starting frequency and an ending frequency less than twice the starting frequency. Recorded signals are processed to generate an image corresponding to at least one point in the subsurface, the processing includes stacking recordings from each sensor for a plurality of actuations of the source, cross correlating the stacked signals with an expected signal generated by non linearities in the subsurface and beam steering a response of the seismic sensors such that the at least one point is equivalent to a focal point of a response of the plurality of sensors. |
