Military Wiki
Project Gnome
A man (arrowed) standing in the cavity created by the Gnome detonation
Country United States
Test series Operation Nougat
Operation Plowshare
Test site Gnome Site
Date December 10, 1961
Test type Underground
Yield 3.1 kt
Gnome Site
Country United States
State New Mexico
County Eddy
Nearest city Loving, New Mexico
Geographic features Mescalero Sands, Centinela Mound
Location 14.5 km east of the Pecos River
 - elevation 1,037 m (3,402 ft)
 - coordinates 32°15′45″N 103°51′55.1″W / 32.2625°N 103.865306°W / 32.2625; -103.865306
Geology Permian, Salado Formation
For public Open
Easiest access New Mexico State Road 128

Project Gnome was the first nuclear test of the Plowshare program and was the first continental nuclear weapon test since Trinity to be conducted outside of the Nevada Test Site. It was tested in southeastern New Mexico, approximately 40 km (25 mi) southeast of Carlsbad, New Mexico.


First announced in 1958, Gnome was delayed by the testing moratorium between the United States and the Soviet Union that lasted from November, 1958 until September, 1961 when the Soviet Union resumed nuclear testing, thus ending the moratorium. The site selected for Gnome is located roughly 40 km (25 mi) southeast of Carlsbad, New Mexico in an area of salt and potash mines along with oil and gas wells.[1]

Unlike most nuclear tests which were focused on weapon development, Shot Gnome was designed to focus on scientific experiments:

  • "Study the possibility of converting the heat produced by a nuclear explosion into steam for the production of electric power."[2]
  • "Explore the feasibility of recovering radioisotopes for scientific and industrial applications."[3]
  • "Use the high flux of neutrons produced by the detonation for a variety of measurements that would contribute to the scientific knowledge in general and to the reactor development program in particular."[4]

It was learned during the 1957 Plumbbob-Rainier tests that an underground nuclear detonation created large quantities of heat as well as radioisotopes but most would quickly become trapped in the molten rock and unusable as the rock resolidifed. For this reason, it was decided that Gnome would be detonated inside a bedded rock salt dome. The plan was to then pipe water through the molten salt and use the steam generated to produce electricity. The hardened salt could be subsequently dissolved in water in order to extract the radioisotopes. Gnome was considered extremely important to the future of nuclear science because it could show that nuclear weapons might be used in peaceful applications. The Atomic Energy Commission invited representatives from various nations, the U.N., the media, interested scientists and some Carlsbad residents.[5]

While Gnome is considered the first test of the Plowshare program, it was also part of the Vela program, which was established in order to improve the ability of the United States to detect underground and high altitude nuclear detonations. Vela Uniform was the phase of the program concerned with underground testing. Everything from seismic signals, radiation, ground wave patterns, electromagnetic pulse, and acoustic measurements were studied at Gnome under Vela Uniform.[6]

Gnome shot and after-effects

Geological section at the Gnome site.

Gnome was placed 361 m (1,184 ft) underground at the end of a 340 m (1,115 ft) tunnel that was supposed to be self-sealing upon detonation. Gnome was detonated on 10 December 1961 with a yield of 3.1 kilotons. Even though the Gnome shot was supposed to seal itself, the plan did not quite work. Two to three minutes after detonation, smoke and steam began to rise from the shaft. Consequently some radiation was released and detected off site, but it quickly decayed.[7] The cavity volume was calculated to be 28,000 ±2,800 cubic meters with an average radius of 17.4m in the lower portion measured.[8]

The Gnome detonation created a cavity 20 m (66 ft) wide and 50 m (164 ft) high with a floor of melted rock and salt which trapped most of the radiation.[9] A new shaft was drilled near the original and on 17 May 1962, crews entered the Gnome Cavity. Even though almost six months had passed since the detonation, the temperature inside the cavity was still around 140° Fahrenheit (60° Celsius). Inside, they found stalactites made of melted salt as well as the walls of the cavity covered in salt.[10] The intense radiation of the detonation colored the salt multiple shades of blue, green, and violet.[2]

Today, all that exists to show what occurred at Gnome is a small concrete monument with two weathered and slightly vandalized plaques.

Monument at the Project Gnome site in March 2004

See also

  • Waste Isolation Pilot Plant


  1. Defense Nuclear Agency, Projects Gnome and Sedan: The Plowshare Program, (Washington D.C.: Defense Nuclear Agency, 1983): 32-34.
  2. 2.0 2.1 DNA, Projects Gnome and Sedan: The Plowshare Program, p. 37.
  3. DNA, Projects Gnome and Sedan: The Plowshare Program, p. 37-38.
  4. DNA, Projects Gnome and Sedan: The Plowshare Program, p. 38.
  5. DNA, Projects Gnome and Sedan: The Plowshare Program, p. 38-40.
  6. DNA, Projects Gnome and Sedan: The Plowshare Program, p. 44-54.
  7. DNA, Projects Gnome and Sedan: The Plowshare Program, p. 36-37.
  9. Dickey, D.D. 1964. Effects of the Gnome nuclear explosion upon rock salt as measured by acoustical methods. United States Geological Survey, Professional Paper 501-B, pp. 108-111.
  10. Gard, L.M. 1963. Nuclear explosions – some geologic effects of the Gnome shot. Science 139(3558):911-914.

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