Monitoring yields of underground nuclear tests using hydrodynamic methods

The yields of nuclear explosions can be estimated using hydrodynamic methods. The approach that has been proposed by the United States for nuclear test ban monitoring makes use of the fact that the initial speed of the expanding shock wave produced by an underground explosion increases with the yield. Several techniques have been developed in the United States to measure the speed of the shock wave, of which the so-called CORRTEX technique is the most recent and best. A variety of algorithms have been used to derive yield estimates from shock wave radius vs. time measurements. Although more intrusive than seismic methods, current hydrodynamic methods could be used to monitor the Threshold Test Ban and Peaceful Nuclear Explosion treaties, provided that appropriate changes in these treaties are negotiated and that adequate coorperative arrangements are made to assure accuracy. Significant engineering, operational, and analysis problems need to be solved before these methods could be used to monitor with confidence a low-threshold test ban. The methods are not relevant to a comprehensive test ban.