The trend in exploration toward the investigation of deeper and geologically more complex structures, necessitates a keener appreciation of the three-dimensional factors involved in evaluating them. For the deep structures, in which dips of 5°-10° are common, it is necessary to migrate the dips to their true position. It is particularly necessary to do this with fault problems; otherwise, the fault trace may be mislocated by ½ mile or more.

By using some of the seismograph instruments at an angle to the line of shot holes, three-dimensional control can be obtained simultaneously with normal continuous profiling methods.

A seismograph interpretation of a faulted structure may be correct geometrically and still may not appear geologically sound until a fourth dimension, geologic time, has been added.

Closer cooperation between the geologist and geophysicist must eventually come, because it is an economic necessity.