Cannikin Shot Cavity
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Cannikin was an underground nuclear weapons test performed on November 6, 1971, on
Amchitka Amchitka (; ;) is a volcanic, tectonically unstable and uninhabited island in the Rat Islands group of the Aleutian Islands in southwest Alaska. It is part of the Alaska Maritime National Wildlife Refuge. The island, with a land area of ro ...
island,
Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
, by the
United States Atomic Energy Commission The United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by the U.S. Congress to foster and control the peacetime development of atomic science and technology. President Harry ...
. The experiment, part of the
Operation Grommet The United States's Grommet nuclear test series was a group of 34 nuclear tests conducted in 1971–1972. These testsA bomb test may be a salvo test, defined as two or more explosions "where a period of time between successive individual explos ...
nuclear test series, tested the unique W71 warhead design for the
LIM-49 Spartan The LIM-49 Spartan was a United States Army anti-ballistic missile, designed to intercept attacking nuclear warheads from intercontinental ballistic missiles at long range and while still outside the atmosphere. For actual deployment, a five-mega ...
anti-ballistic missile. With an explosive yield of almost , the test was the largest underground explosion ever detonated by the United States. Prior to the main five-megaton test in 1971, a test took place on the island on October 2, 1969, for calibration purposes, and to ensure the subsequent Cannikin test could be contained. This test, Milrow, was included in the
Operation Mandrel The United States's Mandrel nuclear test series was a group of 52 nuclear tests conducted in 1969–1970. These tests followed the '' Operation Bowline'' series and preceded the '' Operation Emery'' series. References {{US Nuclear Test ...
nuclear test series. The Cannikin test faced considerable opposition on environmental grounds. The campaigning environmental organization
Greenpeace Greenpeace is an independent global campaigning network, founded in Canada in 1971 by a group of Environmental movement, environmental activists. Greenpeace states its goal is to "ensure the ability of the Earth to nurture life in all its biod ...
grew out of efforts to oppose the test.


Siting

The Cannikin test was too large to be conducted safely at
Nevada Test Site The Nevada National Security Sites (N2S2 or NNSS), popularized as the Nevada Test Site (NTS) until 2010, is a reservation of the United States Department of Energy located in the southeastern portion of Nye County, Nevada, about northwest of ...
. Amchitka had been considered in the 1950s as a potential nuclear test site, but had been deemed unsuitable at that time. In 1965, a single nuclear test, ''Long Shot'', was carried out on the island for the purposes of seismic detection development, under program
Vela Uniform Vela Uniform was an element of Project Vela conducted jointly by the United States Department of Energy and the Advanced Research Projects Agency. Its purpose was to develop seismic methods for detecting underground nuclear testing, and it involv ...
. The Amchitka site was again investigated as an atmospheric nuclear test site for
intercontinental ballistic missile An intercontinental ballistic missile (ICBM) is a ballistic missile with a range (aeronautics), range greater than , primarily designed for nuclear weapons delivery (delivering one or more Thermonuclear weapon, thermonuclear warheads). Conven ...
silo design under Project Rufus in the 1960s, but the atmospheric testing component was abandoned following the establishment of the
Partial Nuclear Test Ban Treaty The Partial Test Ban Treaty (PTBT), formally known as the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, prohibited all nuclear weapons testing, test detonations of nuclear weapons except for those co ...
.


Preparation

Preparation for the test took place over five years and involved hundreds of staff from the Lawrence Radiation Laboratory, later the
Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a Federally funded research and development centers, federally funded research and development center in Livermore, California, United States. Originally established in 1952, the laboratory now i ...
. Drilling for the shaft for the ''Milrow'' test began in March 1967, with drilling for the Cannikin test commencing in August 1967. To perform the test, 400 tons of equipment was placed in a shaft deep and wide. Test support equipment was designed to survive a ground upheaval of at test time. The chairman of the Atomic Energy Commission,
James R. Schlesinger James Rodney Schlesinger (February 15, 1929 – March 27, 2014) was an American economist and statesman who was best known for serving as Secretary of Defense from 1973 to 1975 under Presidents Richard Nixon and Gerald Ford. Prior to becom ...
, brought his wife and two daughters to Amchitka for the test to emphasize the safety of the test.


Opposition

Both the 1969 calibration test and Cannikin itself attracted protest. Because of the
1964 Alaska earthquake The 1964 Alaska earthquake, also known as the Great Alaska earthquake and Good Friday earthquake, occurred at 5:36 PM Alaska Standard Time, AKST on Good Friday, March 27, 1964.
, the plans raised concerns that tests might trigger earthquakes and cause a
tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...
. A 1969 demonstration of 7,000 people blocked a major U.S.–Canada border crossing in British Columbia, carrying signs reading "Don't Make A Wave. It's Your Fault If Our Fault Goes". Further demonstrations occurred at Canada–US border crossings in Ontario and Quebec. The Canadian
Don't Make a Wave Committee The Don't Make a Wave Committee was the name of the anti-nuclear organization which later evolved into Greenpeace, a global environmental organization. The Don't Make a Wave Committee was founded in Vancouver, British Columbia, Canada to protest a ...
, founded that year in
Vancouver Vancouver is a major city in Western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the cit ...
, attempted to halt further nuclear testing on the
Aleutian Islands The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi language, Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before Alaska Purchase, 1867, the Catherine Archipelago—are a chain ...
chain. With the intention of sailing to Amchitka to protest the 1971 test, the committee chartered a ship it renamed ''
Greenpeace Greenpeace is an independent global campaigning network, founded in Canada in 1971 by a group of Environmental movement, environmental activists. Greenpeace states its goal is to "ensure the ability of the Earth to nurture life in all its biod ...
''. During the voyage to Amchitka, the test was delayed a month. The ship was turned back by the U.S. Coast Guard, although a letter given to the ''Greenpeace'' crew showed support for the protest by some on the intervening Coast Guard ship. Under their own ship's name, the organization created for the protest continued to exist as the campaigning environmental organization
Greenpeace Greenpeace is an independent global campaigning network, founded in Canada in 1971 by a group of Environmental movement, environmental activists. Greenpeace states its goal is to "ensure the ability of the Earth to nurture life in all its biod ...
. In July 1971, the anti-nuclear
Committee for Nuclear Responsibility The Committee for Nuclear Responsibility was formed as a "political and educational organization to disseminate anti-nuclear views and information to the public". The goals of the organization were a moratorium on nuclear power and the commercializa ...
filed suit against the Atomic Energy Commission, asking the court to stop the test. The suit was unsuccessful, with the
Supreme Court In most legal jurisdictions, a supreme court, also known as a court of last resort, apex court, high (or final) court of appeal, and court of final appeal, is the highest court within the hierarchy of courts. Broadly speaking, the decisions of ...
denying the injunction by 4 votes to 3. The test was carried out but, although it triggered small earthquakes, did not cause a tsunami as feared.


Test results

Cannikin was detonated on November 6, 1971 , as the thirteenth test of the
Operation Grommet The United States's Grommet nuclear test series was a group of 34 nuclear tests conducted in 1971–1972. These testsA bomb test may be a salvo test, defined as two or more explosions "where a period of time between successive individual explos ...
(1971–1972) underground nuclear test series. The announced yield was 5 megatons (21 PJ) – the largest underground nuclear test in U.S. history. (Estimates for the precise yield range from 4.4 to 5.2 megatons or 18 to 22 PJ). The ground lifted , caused by an explosive force almost 400 times the power of the Hiroshima bomb. Subsidence and faulting at the site created a new lake, several hundred meters wide. The explosion caused a seismic shock of 7.0 on the
Richter scale The Richter scale (), also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, is a measure of the strength of earthquakes, developed by Charles Richter in collaboration with Beno Gutenberg, and pr ...
, causing rockfalls and turf slides of a total of . Though earthquakes and tsunamis predicted by environmentalists did not occur, a number of small tectonic events did occur in the following weeks, (some registering as high as 4.0 on the Richter scale) thought to be due to the interaction of the explosion with local tectonic stresses.


See also

*
Military history of the Aleutian Islands The military history of the Aleutian Islands began almost immediately following the purchase of Alaska from the Russian Empire by the United States in 1867. Prior to the early 20th century, the Aleutian Islands were essentially ignored by the Uni ...


References

{{US Nuclear Tests Underground nuclear weapons testing