Photogrammetric Mapping of Craters from Small Explosions

The possible future use of nuclear explosives for large-scale excavation projects has led to small-scale investigation of cratering and ejecta mechanisms using chemical explosive charges. Information obtained from explosive experiments will guide further testing and be instrumental in determining placement and charge sizes for nuclear explosive earth moving. Photogrammetric techniques have been developed which enable rapid accurate measurement of crater dimensions. Ground-supported stereo photography is utilized before and after explosions for mapping with contour lines at 0.2-foot intervals and spot elevations at 0.1-foot accuracy. A similar technique with a horizontal line of sight is used to locate in three dimensions gages which measure geometry and strength of the blast wave as it vents from the ground.