Seismo-Acoustic Yield Determination of Explosions

Abstract:

In recent work (Pasyanos and Kim, 2019), we have performed a joint seismic-acoustic inversion for yield for surface and buried chemical events at the Nevada National Security Site, as part of the Source Physics Experiment (SPE). As widely observed, there is a very strong tradeoff between the recorded seismic and acoustic signals and the height or depth of the explosion. While this is also true for explosions at depth, this effect is much larger for near surface events. Combining the seismic and acoustic analyses narrows the range of possible yields and depth/height, and significantly reduces the uncertainties on these parameters.

We continue to refine and expand the method by applying our analysis to new sets of events in other regions of the world, and in different tectonic regimes. These events include ordnance explosions and explosions conducted for geophysical exploration. In the first case, where we have repeated explosions of the same yield and depth, we see a consistent seismic signal, while the acoustic signal varies significantly. In relatively well-buried exploration explosions, there is often no acoustic signal observed at regional distances even though the atmospheric conditions were favorable to observe them. In this instance, the lack of signal can still provide information on maximum yield/depth, and this information can be included in the joint analysis to reduce the allowable range of explosion source parameters.