Computer Stereograms of Subsurface Geology

Harry W. Todd

Three-dimensional stereoscopic illustrations formerly have not been a standard part of the subsurface geologist's toolkit. Now the immense complexity of stereograms can be resolved by inexpensive software on a personal computer. The construction technique is a simple combination of known technology. The subsurface geologist can gain an entirely new viewpoint. These new illustrations yield new patterns, new relationships, and prospective anomalies.

Stereograms are particularly effective for displaying and interpreting complex geology in a simple way. Experienced geologists sometimes can fail to appreciate the vertical relationships involved in contour maps. Stereograms provide a more natural view of the data. They are useful also for presenting subsurface geology to persons unfamiliar with standard contouring methods and for clarifying vertical relationships to more experienced viewers.

The purpose of this study is to present a regional sampling of this new mode of geologic illustration. Oklahoma, west Texas, and the Gulf Coast were chosen because of the wide variety of structural and stratigraphic styles, the prolific reserves associated with entrapments, and the abundance of subsurface geologic data and published maps.

Contour maps and block diagrams were constructed with readily available, inexpensive software using kriging algorithms. Stereo pairs were created by rotating the blocks 4 degrees within the computer program. The pairs were positioned 2.5 in. apart to match an average viewer's interpupillary distance. The three-dimensional blocks may be viewed with a stereoscope or with naked eyes focused upon a distant point.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.