Tectonic strain readjustments associated with large underground explosions have been observed at the Nevada Test Site. The Benham event of December 19, 1968 produced a peak quasi-static radial strain of 1.2 × 10−7 at a distance of 29 km. This strain transient was followed by an exponential return to the initial state with a time constant of 13 minutes, and is interpreted as the direct elastic response of the medium to a time varying pressure in the Benham cavity. An upper bound on the tectonic strain release was determined to be 0.7 × 10−8. Using these measurements it is estimated that the permanent and quasi-static strains associated with this explosion could significantly effect local earthquake occurrences out to distances of about 15 km. The size distribution of aftershocks of this explosion resembles that seen in model experiments of brittle fracture, in which the distribution is controlled by the dimensions of inhomogeneities in the medium.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not have access to this content, please speak to your institutional administrator if you feel you should have access.