Abstract: A fracture-evaluation experiment in conjunction with the Shoal nuclear detonation in granite was undertaken to determine the extent of subsurface shock-induced fractures. Preshot and postshot geophysical logs in a hole drilled from the surface through the zone of fractures indicated that fractures extended at least 5.3 cavity radii laterally from the point of detonation. Quantitative measurements of permeability increases resulting from the detonation were planned, but were not completed because of adverse test-hole conditions. General descriptions of the Shoal Project, geology of the test site, and other effects of the detonation are included.
From introduction: This report documents the preshot and postshot condition of all structures within 10 miles of Ground Zero, plus structures at Salt Wells and surface structures at mines that were included in the mine survey.