Ground effects from the Boxcar and Benham nuclear explosions

Formulas were developed by the authors in 1957 for the purpose of estimating maximum ground accelerations and transitory displacements resulting from the 1.7 kt Rainier shot and subsequent underground nuclear detonations. These formulas when extrapolated more than 4 orders of magnitude upward came within a half order of magnitude of predicting ground motion data resulting from the Boxcar and Benham underground detonations. Velocity response spectra from these shots made in the distance range of 20 km, more or less, closely resembled the velocity response spectra from a magnitude 6.6 earthquake in the same distance range.