Experimental Results of USSR Nuclear Explosion Decoupling Measurements

This report was presented at the 14th annual PLDARPA Seismic Research Symposium on September 16, 1992. In it, we describe a decoupling experiment undertaken by the former Soviet Union at Azghir, north of the Caspian Sea. The properties of the cavity are given, including a rough description of the geology salt-dome overlain by 275 m radius sphere, 987 m deep, velocities, densities, etc. These shots had larger yields than the Salmon-Sterling decoupling experiments undertaken by the U.S. in the mid-sixties. Like the U.S. experiment, this Soviet experiment did not achieve full decoupling. The energy decoupling factor computed from statistical relationships between the yield and amplitude-distance curves rather than spectra increased to a maximum of 30 as distance increase. Based on our observations and theoretical limits to decoupling, we conclude that a fully decoupled 1 kt explosion could be observed at a distance of 2,500 km.