Outrunning Ground Shock Computed with Different Models

Abstract

The ground shock response is calculated for a layered site under the airblast loading from a nuclear burst, using two advanced mathematical models, i.e., the variable moduli and CAP models. The computed time histories of the motion from the two calculations are compared at several ranges, extending from the superseismic region into the outrunning region. The major difference in the radial velocity wave forms in the outrunning region corresponds to stress path segments of near neutral loading in shear in the variable moduli calculation. Since this model fails to satisfy the continuity condition of Handelman, Lin, and Prager along such paths, the resulting radial motion waveforms in the outrunning region are highly suspect. The failure of the variable moduli model to satisfy the continuity condition is thus seen to result in more than purely academic consequences.