Yields of US and Soviet Nuclear Tests

The likelihood that the United States will negotiate a comprehensive or lowthreshold test ban treaty with the Soviet Union in the relatively near future depends not only on the ability of the US to monitor such an agreement but also on US perception of past Soviet compliance with treaties that limit nuclear testing. Of particular importance is the 1974 Threshold Test Ban Treaty, which prohibits tests of nuclear weapons exceeding 150 kilotons in yield. This treaty is unratified, but both the United States and the Soviet Union have avowed their compliance since 1976, when the treaty was scheduled to go into effect. (For an annotated list of treaties, see Herbert York's article in PHYSICS TODAY, March 1983, page 24.)