Ground motions resulting from a pressurized buried cavity

The motions at the free surface of an elastic solid due to the presence of an underground explosive source are numerically evaluated. This information is subsequently processed in a form suitable for inferring the strength of the explosion from surface motion measurements. Furthermore, the motions at the surface of the explosive source are also examined. A direct, time-stepping boundary element methodology is used for studying this transient, three-dimensional problem. The solid is modeled as a linear elastic halfspace and the underground blasts are simulated by dynamic radial expansion of the spherical cavity. Parametric studies are conducted that take into account the time variation of the radial expansion, the depth of embedment, and changes in Poisson's ratio.