This Day in Nuclear Weapons Testing History – December 21
Summary:
U.S. tests: 4 (5 devices)
Russian tests: 1
Total yield: 34.6 kilotons.
The Details:
1972 – ‘Flax-Source’detonated in a vertical shaft 1,440 feet (440m) beneath Yucca Flat area U2 at 20:15:00 GMT with a yield of 20 kilotons from the LLNL weapons development device during Operation Toggle, causing a 5.0 magnitude ground shock and creating a 583 foot (178m) diameter subsidence crater. 716th U.S. test. Coordinates: 37.13997, -116.08415.
— Twenty-four seconds later at 20:15:24 GMT, ‘Flax-Test’and ‘Flax-Backup’ detonated simultaneously in the same shaft 2,257 (688m) beneath Yucca Flat area U2 with unspecified yields from the two LLNL devices as part of a weapons effects test. 717thU.S. test. Coordinates: 37.13997, -116.08415.
1976 – ‘Asiago’detonated in a vertical shaft 1,085 feet (330m) beneath Yucca Flat area U2 at 15:09 GMT with a yield of 11 kilotons from the LLNL weapons development device during Operation Fulcrum, creating a 557 foot (170m) subsidence crater. 805th U.S. test. Coordinates: 37.12386, -116.06833.
— Forty-nine minutes later at 15:58 GMT, ‘Sutter’ detonated 657 feet (200m) beneath Yucca Flat area 2 with an unspecified yield from the LLNL weapons development device during Operation Fulcrum. 806th U.S. test. Coordinates: 37.15205, -116.06454.
1979 – ‘674’ detonated in a tunnel within Degelen Mountain, Semipalatinsk at 04:42 GMT with a yield of 3.6 kilotons from the weapons development device, causing a 4.71 magnitude ground shock. 541st Russian test.