Seismic surveying utilizing models

Claim 1

A SEISMIC MODEL FOR ONE SUBSURFACE EARTH LAYER HAVING UPPER AND LOWER BOUNDARIES WHERE INCIDENT SEISMICWAVE ENERGY IS PARTIALLY TRANSMITTED AND PARTIALLY REFLECTED, SAID MODEL COMPRISING TWO ADJUSTABLE TIME-DELAY AND TRANSMISSION CHANNELS EACH HAVING TIME-DELAY CHARACTERISTICS REPRESENTATIVE OF SEISMIC WAVE PROPAGATION OF ENERGY SO AS TO TRANSMIT SIGNALS SIMULATING A SEISMIC IMPULSE TRAVELING IN SAID LAYER WITH A TIME DELAY PROPORTIONAL TO THE ONE-WAY TRAVEL TIME OF SEISMIC WAVES THROUGH SAID LAYER, SAID TWO CHANNELS CORRESPONDING TO SAID LAYER WHEN TRANSMITTING SEISMIC PARTICLE MOTION RESPECTIVELY DOWNWARDLY AND UPWARDLY, ADJUSTABLE ELECTRICAL NETWORK MEANS COUPLED TO THE OUTPUT OF EACH OF SAID CHANNELS FOR DIVIDING SAID OUTPUT INTO TWO PORTIONS WHICH CORRESPOND TO THE EARTH PARTICLE MOTIONS RESPECTIVELY REFLECTED BY AND TRANSMITTED ACROSS ONE OF SAID BOUNDARIES, AND CONNECTING MEANS BETWEEN SAID OUTPUT-DIVIDING MEANS OF EACH OF SAID CHANNELS AND THE INPUT OF THE OTHER OF SAID CHANNELS FOR APPLYING TO SAID INPUT THE SIGNALS REPRESENTATIVE OF SAID REFLECTED EARTH-PARTICLE MOTIONS.