– An exploration technique used in the search for oil and gas underground structures. The basic premise behind seismic is the same as ultra sound technology used in the medical field. Sound from a shot hole is recorded from geophones and interpreted to give a picture of the underlying structures within the earth. 3-D has now become a common practice to redefine and identify known as well as unknown structures. Many times these structures contain traps that hold oil and gas yet to be discovered. .