Answers are grounded in this paper and cite their sources.
It is shown theoretically that the seismic signal from an underground nuclear explosion can be greatly reduced by carrying out the explosion in a large cavity. An estimate of the effectiveness of the method indicates that a yield of more than 300 kilotons (HE-equivalent) could be made to look seismically like a yield of 1 kiloton. Experiments with both chemical and nuclear explosions are needed to test the theory.
No takes yet. Share an insight, caveat, or question.
Latter et al. (1961) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: