Amchitka (Amchixtax̂ in Aleut) is a volcanic, tectonically unstable island in the Rat Islands group of the Aleutian Islands in southwest Alaska. It is about long, and varies from 3 to 6 km (2–3.75 mi) in width. It has a maritime climate, with many storms, and mostly overcast skies.
The island was populated for more than 2,500 years by the Aleut people, but has had no permanent population since 1832. It was included in the Alaska Purchase of 1867, and has since been part of the United States. During World War II, it was used as an airfield by US forces in the Battle of the Aleutian Islands.
Amchitka was selected by the United States Atomic Energy Commission to be the site for underground detonations of nuclear weapons. Three such tests were carried out: Long Shot, an 80 kiloton blast in 1965; Milrow, a 1 megaton blast in 1969; and Cannikin in 1971 at "under 5 megatons", the largest underground test ever conducted by the United States. The tests were highly controversial, with environmental groups fearing that the Cannikin explosion, in particular, would cause severe earthquakes and tsunamis.
Amchitka is no longer used for nuclear testing, although it is monitored for the leakage of radioactive materials.
The eastern part of the island is a lowland plateau, with isolated ponds and gently rolling hills. There is low but abundant vegetation, consisting of mosses, lichens, liverworts, ferns, grasses, sedges, and crowberry. The centre of the island is mountainous, and the western end is barren and vegetation is sparse.
Amchitka has a maritime climate, often foggy and windswept, with cloud cover 98 percent of the time. While temperatures are moderated by the ocean, storms are frequent. Geologically, the island is volcanic, being a part of a small crustal block on the Aleutian Volcanic Arc that is being torn apart by oblique subduction. It is "one of the least stable tectonic environments in the United States."
The human history of Amchitka dates back at least 2,500 years, with the Aleut people. Human remains, thought to be of an Aleut and dating from about 1000 AD, were discovered in 1980.
In 1783, 15 Japanese castaways led by Daikokuya Kōdayū landed on the island. Within three years, six died there. The castaways were under the protection of Russian workers whose leader was Nevisimov (ネビジモフ), an employee of a furrier in Moscow named Vassily Yakovlevic Zhigarev (ヴァシリー・ヤコブレヴィチ・ジガーレフ). The Japanese voluntarily started to work with Aleut people and observed a relationship between Russians and Aleuts. After they got back to Japan, one castaway, Isokichi (磯吉), told a Japanese scholar: "Russians robbed furs that Aleuts got. If they got angry at Russians and did not get any furs or got few furs, the man got beaten nearly to death. If one man did not obey orders by Russians, he would be killed." The furs were divided into thirds between the Russian Empire, Vassily Zhigarev, and the workers. Together with some Russians, nine castaways (and a cat) escaped from the island in 1787 on a new ship that they built from driftwood and nails.
Islanders received necessities and supplies such as tobacco, ironware, horse- and ox-skins, and cotton in return for hunting otters or seals.
Russian trappers and traders established settlements on the islands, exploiting the indigenous people, whose population on the island quickly fell. From 1832, the island was never permanently inhabited, and by the time of World War II, an abandoned Russian fishing village was all that remained. The islands were surveyed by the North Pacific Exploring Expedition in 1855, and were included in the Alaska Purchase of 1867. In 1913, President William Taft set aside the Aleutian chain, including Amchitka, as a wildlife preserve. The Native residents of Atka leased the island for fox hunting in 1920, and continued to use the island until the Japanese invasion of the western Aleutians in 1942.
In June 1942, the Japanese occupied some of the western Aleutian islands, and hoped to occupy Amchitka. Eager to remove the Japanese, the Joint Chiefs of Staff agreed to move quickly to regain the territory. American planners decided to build a series of airfields to the west of Umnak, from which bombers could attack the invading forces.
The U.S. Army established bases at Adak and 13 other locations. At the War Department's suggestion, an initial reconnaissance of Amchitka was carried out in September 1942, which found that it would be difficult to build an airstrip on the island. Nevertheless, planners decided on December 13 that the airfield "had to be built" to prevent the Japanese from doing the same. A further reconnaissance mission visited Amchitka from 17–19 December, and reported that a fighter strip could be built in two to three weeks, and a main airfield in three to four months.
The plan would go ahead. American forces made an unopposed landing on Amchitka on January 12, 1943, although the destroyer grounded and sank with the loss of 14 lives. Despite facing difficult weather conditions and bombing from the Japanese, the airfield was usable by February 16. The Alaska Command was now away from their target, Kiska. The military eventually built numerous buildings, roads, and a total of three airstrips on the island, some of which would later be renovated and used by the Atomic Energy Commission. At its peak, the occupancy of Amchitka reached 15,000 troops.
The Aleutian Islands campaign was successfully completed on August 24, 1943. In that month, a strategic intercept station was established on the island, which remained until February 1945. The Army abandoned the site in August 1950. The site later hosted an Air Force weather station in the 1950s, a White Alice telecommunication system in 1959 to 1961, and a temporary relay station in the 1960s and 1970s.
The Department of Defense initially considered the island for nuclear testing planned for 1951. Requiring information about the cratering potential of nuclear weapons, plans were made to detonate two 20-kiloton devices. After drilling approximately 34 test holes, the site was deemed unsuitable, and the project was moved to the Nevada test site.
In the late 1950s, scientists realised that improved seismological knowledge was necessary for the detection of Soviet underground nuclear explosions. The 1.7 kiloton "Rainier" test (part of Operation Plumbbob, performed elsewhere) produced strong seismic signals, but looked much like an ordinary earthquake. In 1959, Dr. James R. Killian, the Special Assistant to the President for Science and Technology, formed the Panel on Seismic Improvement (which subsequently recommended the program that came to be known as Vela Uniform), with the twin goals of improving seismic instruments and deploying them globally, and researching in more depth the seismic effects of nuclear explosions. The project was subsequently initiated by the Eisenhower administration.
Together with the Atomic Energy Commission, the DoD began assessing Amchitka for use as part of the Vela Uniform tests.
To conduct the Vela Uniform test on the island, Long Shot, the Department of Defense occupied Amchitka from 1964 to 1966, with the AEC providing the device, measuring instruments, and scientific support. The goal was "to determine the behavior and characteristics of seismic signals generated by nuclear detonations and to differentiate them from seismic signals generated by naturally occurring earthquakes."
Although it would not be publicly announced until 18 March, 1965, senior Alaskan officials were notified the previous February. After the devastating Great Alaska Earthquake of 27 March, 1964, the governor expressed concern about the psychological effects of the test on the populace. He was quickly reassured.
Long Shot was detonated on October 29, 1965, and the yield was 80 kilotons. It was the first underground test in a remote area, and the first test managed by the DoD. While there was no surface collapse, tritium and krypton were found at the surface following the test; this was not made public until 1969.
Though performed as part of the Nuclear Weapons Testing Program, "[the] purpose of the Milrow test was to test an island, not a weapon." It was a "calibration shot", intended to produce data from which the impact of larger explosions could be predicted, and specifically, to determine whether the planned Cannikin shot could be performed safely. Milrow was detonated on 2 October, 1969, with an approximate yield of 1 to 1.2 megatons. (image: www.kadiak.org/aleutians/amchitka_milrow.jpg)
The shockwave reached the surface with an acceleration of over 35g, causing a dome of the earth's surface, approximately in radius, to rise about 5 metres. The blast "turned the surrounding sea to froth" and "forced geysers of mud and water from local streams and lakes into the air" A "surface collapse feature," also known as a subsidence crater, was formed by material collapsing into the cavity formed by the explosion.
Cannikin was intended to test the design of the Spartan anti-ballistic missile (ABM) interceptor – a high-yield warhead that "produced copious amounts of x-rays and minimized fission output and debris to prevent blackout of ABM radar systems." The test would "measure the yield of the device, measure the x-ray flux and spectrum, and assure deployment of a reliable design."
The Committee's name referred to predictions made by a Vancouver journalist named Bob Hunter, later to become Greenpeace member 000. He wrote that the test would cause earthquakes and a tsunami. The AEC considered the likelihood of the test triggering a severe earthquake "very unlikely," unless one was already imminent on a nearby fault, and considered a tsunami "even more unlikely."
Others disagreed. Russell Train, then Chairman of the Council on Environmental Quality, argued that "experience with Milrow ... does not provide a sure basis for extrapolation. In the highly nonlinear phenomena involved in earthquake generation, there may be a threshold value of the strain that must be exceeded prior to initiation of a large earthquake. ... The underground explosion could serve as the first domino of the row of dominoes leading to a major earthquake. ... as in the case of earthquakes it is not possible at this time to assess quantitatively the probability of a tsunami following the explosion."
In July 1971, a group called the Committee for Nuclear Responsibility filed suit against the AEC, asking the court to stop the test. The suit was unsuccessful, with the Supreme Court denying the injunction by 4 votes to 3, and Richard Nixon personally authorised the $200 million test, in spite of objections from Japan, Peru, and Sweden. The Don't Make A Wave Committee chartered a boat, in which they had intended to sail to the island in protest, but due to weather conditions they were unable to reach their destination.
Cannikin was detonated on 6 November, 1971. The announced yield was "less than five" megatons – the largest underground nuclear test in US history. (Estimates for the precise yield range from 4.4 to 5.2 Megatons). The ground lifted , caused by an explosive force equivalent almost 400 times the power of the Hiroshima bomb. Subsidence and faulting at the site created a new lake, over a mile wide. The explosion caused a seismic shock of 7.0 on the Richter scale, 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, thought to be due to the interaction of the explosion with local tectonic stresses.
The DoE withdrew from the island in 1973, though scientists continued to visit the island for monitoring purposes. In 2001, the DoE returned to the site to remove environmental contamination. Drilling mud pits were stabilized by mixing with clean soil, covering with a polyester membrane, topped with soil and re-seeded.
Concerns have been expressed that new fissures may be opening underground, allowing radioactive materials to leak into the ocean. A 1996 Greenpeace study found that Cannikin was leaking both plutonium and americium into the environment, though a 2004 University of Alaska, Fairbanks study reported that "There were no indications of any radioactive leakage, and all that was really wonderful news." Similar findings are reported by a 2006 study, which found that levels of plutonium were "were very small and not significant biologically".
The Department of Energy continues to monitor the site as part of their remediation program. This is expected to continue until 2025, after which the site is intended to become a restricted access wildlife preserve.
|Long Shot||1965-10-29 21:00||80 kt||shaft|
|Milrow||1969-10-02 22:06||~ 1 Mt||shaft|
|Cannikin||1971-11-06 22:00||< 5 Mt||shaft|
The following links are to Department of Energy films about the Amitchka test facility. The videos include footage of the tests.