GRAVITY Gravity surveying measures variations in the Earth's gravitational field caused by the differences in the density of subsurface rocks. Gravity methods have been used most extensively in the search for oil and gas GEOSEARCHES, Inc. PO BOX 37 CHAGRIN FALLS OHIO,44022 TEL - (440) 893-0642 FAX - (440) 893-0646 TOLL FREE - 1 866 442 4425 Email: hamill@geosearches.com