Geologic effects of the Benham underground nuclear explosion, Nevada Test Site

The Benham event, an underground nuclear explosion with a yield of about 1 megaton, produced linear fracture zones along previously mapped Basin and Range faults as far as 5.6 km (kilometers) from the explosion. The sense of vertical displacement on the faults and associated fractures is usually the same, with as much as 46 cm (centimeters) of vertical displacement and 15 cm of right-lateral displacement on the fractures. Displacements on the fractures reflect the release of tectonic strain triggered by the explosion; the parameters of the principal zone of fractures are similar to those expected for a natural earthquake of magnitude M = 6.0, which is also the instrumentally determined magnitude for the explosion reported by the U.S. Coast and Geodetic Survey.