Infrasound and Infrasonic Monitoring of Atmospheric Nuclear Explosions: Past Monitoring Efforts

This report presents the results of an unclassified review and discussion of past U.S. programs directed toward the infrasonic monitoring of atmospheric nuclear explosions. In brief, the U.S. monitored virtually all atmospheric nuclear explosions conducted by China, France, the former Soviet Union and the United States. The first nuclear explosion to be infrasonically monitored was the 21 KT air-dropped Able test which was conducted at the Bikini test site in the south-Pacific on June 30, 1946, and the last nuclear explosion which was infrasonically monitored was the 3 MT Chinese test which occurred on November 17, 1976. The review of the detection performance of continental stations used to monitor U.S. tests at the NTS indicates that maximum detection ranges for explosions of - 1 KT can vary from 1350 km to 3585 km depending on the noise levels at a particular station and on the environmental conditions along the propagation path. In addition, recent work utilizing still classified data acquired during the existence of the USAEDS infrasound program as well as other independent estimates is discussed which indicates that a proposed 60 station infrasound network can ensure detection of a 1 KT atmospheric test with a location uncertainty of 100 km over most of the earth