Seismic surveying with an impulse pattern consisting of positive and negative impulses

Claim 1

A METHOD OF SEISMIC PROSPECTING IN WHICH THE AUTOCORRELATION FUNCTION OF A PLURALITY OF DISCRETE IMPULSES OF INCREASING TIME OF APPLICATION AND GENERALLY OF DECREASING PEAK AMPLITUDE HAS BEEN DETERMINED, SAID TIME OF APPLICATION AND PEAK AMPLITUDE OF SAID IMPULSES HAVING BEEN VARIED UNTIL THE MAXIMUM LOBE OF SAID FUNCTION IS AT LEAST 10 TIMES THE AMPLITUDE OF ANY SIDE LOBE OF SAID FUNCTION, WHEREBY AN IMPULSE PATTERN OF POSITIVE AND NEGATIVE IMPULSES IS ESTABLISHED, COMPRISING: (1) APPLYING TO THE EARTH AT A LOCALIZED ZONE A PLURALITY OF COMPRESSIONAL IMPULSES DIRECTLY PROPORTIONAL IN TIME OF APPLICATION AND IN PEAK AMPLITUDE TO THE CORRESPONDING CHARACTERISTICS OF ONE ONLY OF SAID POSITIVE AND SAID NEGATIVE IMPULSE PATTERN, (2) RECEIVING THE SEISMIC WAVES RESULTING FROM STEP (1) AT LEAST NEAR THE SURFACE OF THE EARTH AND REPRODUCIBLY RECORDING SAID WAVES, (3) APPLYING TO SAID ZONE A PLURALITY OF COMPRESSIONAL IMPULSES DIRECTLY PROPORTIONAL INTIME OF APPLICATION AND IN PEAK AMPLITUDE TO THE CORRESPONDING CHARACTERISTICS OF THE OTHER OF SAID POSITIVE AND SAID NEGATIVE IMPULSE PATTERN, THE PROPORTIONALITY FACTORS BEING SUBSTANTIALLY IDENTICAL TO THOSE OF STEP (1), (4) RECEIVING THE SEISMIC WAVES RESULTING FROM STEP (3) AT LEAST NEAR THE SURFACE OF THE EARTH AND REPRODUCIBLY RECORDING SAID WAVES, AND (5) PRODUCING A VISIBLE INDICATION SHOWING THE DIFFERENCE BETWEEN THE CROSS-CORRELATION OF SAID PATTERN OF POSITIVE AND NEGATIVE IMPULSES WITH THE WAVES RECORDED IN STEPS (2) AND (4) USING THE SAME TIME SCALE FOR SAID PATTERN AND FOR SAID WAVES.

Claim 2

A METHOD OF SEISMIC PROSPECTING IN WHICH THE AUTOCORRELATION FUNCTION OF A PLURALITY OF DISCRETE IMPULSES OF INCREASING TIME OF APPLICATION AND GENERALLY OF DECREASING PEAK AMPLITUDE HAS BEEN DETERMINED, SAID TIME OF APPLICATION AND PEAK AMPLITUDE OF SAID IMPULSES HAVING BEEN VARIED UNTIL THE MAXIMUM LOBE OF SAID FUNCTION IS AT LEAST 10 TIMES THE AMPLITUDE OF ANY SIDE LOBE OF SAID FUNCTION, WHEREBY AN IMPULSE PATTERN OF POSITIVE AND NEGATIVE IMPULSES IS ESTABLISHED, COMPRISING: (1) APPLYING TO THE EARTH AT A LOCALIZED ZONE A PLURALITY OF COMPRESSIONAL IMPULSES DIRECTLY PROPORTIONAL IN TIME OF APPLICATION AND IN PEAK AMPLITUDE TO THE CORRESPONDING CHARACTERISTICS OF ONE ONLY OF SAID POSITIVE AND SAID NEGATIVE IMPULSE PATTERN, (2) RECEIVING THE SEISMIC WAVES RESULTING FROM STEP (1) AT LEAST NEAR THE SURFACE OF THE EARTH AND REPRODUCIBLY RECORDING SAID WAVES, (3) APPLYING TO SAID ZONE A PLURALITY OF COMPRESSIONAL IMPULSES DIRECTLY PROPORTIONAL INTIME OF APPLICATION AND IN PEAK AMPLITUDE TO THE CORRESPONDING CHARACTERISTICS OF THE OTHER OF SAID POSITIVE AND SAID NEGATIVE IMPULSE PATTERN, THE PROPORTIONALITY FACTORS BEING SUBSTANTIALLY IDENTICAL TO THOSE OF STEP (1), (4) RECEIVING THE SEISMIC WAVES RESULTING FROM STEP (3) AT LEAST NEAR THE SURFACE OF THE EARTH AND REPRODUCIBLY RECORDING SAID WAVES, AND (5) PRODUCING A VISIBLE INDICATION SHOWING THE DIFFERENCE BETWEEN THE CROSS-CORRELATION OF SAID PATTERN OF POSITIVE AND NEGATIVE IMPULSES WITH THE WAVES RECORDED IN STEPS (2) AND (4) USING THE SAME TIME SCALE FOR SAID PATTERN AND FOR SAID WAVES.