METHOD OF AND APPARATUS FOR EXPLORING A REGION BELOW A SURFACE OF THE EARTH

摘要

A passive method is provided for exploring a region below the surface of the earth. The method comprises using a single sensor located in turn at a plurality of locations to obtain seismic data obtained by recording ambient seismic interface waves in a frequency range whose lower limit is greater than OHz, and whose upper limit is less than or equal to substantially 1 Hz. The data are processed (41-44) so as to obtain a measure of the energy in a frequency band within the frequency range. For example, the seismic data may be filtered (41 ) and may be subjected to amplitude normalisation (42) before being transformed (43) into the frequency domain. The energy measure may then be calculated (44) by integrating the spectrum in the frequency domain over a desired frequency range. The resulting calculated energy provides information about the region of the earth being explored.