Enewetak Atoll

Enewetak Atoll (/ɛˈniːwəˌtɔːk, ˌɛnɪˈwiːtɔːk/;[2] also spelled Eniwetok Atoll or sometimes Eniewetok; Marshallese: Ānewetak, [æ̯ænʲee̯ɔ̯ɔ͡ɛɛ̯dˠɑk], or Āne-wātak, [æ̯ænʲee̯-ɒ̯ɒ͡ææ̯dˠɑk][3]) is a large coral atoll of 40 islands in the Pacific Ocean and with its 664 people (as of 2011)[1] forms a legislative district of the Ralik Chain of the Marshall Islands. With a land area total less than 5.85 square kilometres (2.26 sq mi)[1], it is no higher than 5 meters and surrounds a deep central lagoon, 80 kilometres (50 mi) in circumference. It is the second-westernmost atoll of the Ralik Chain and is 305 kilometres (190 mi) west from Bikini Atoll.

Nuclear testing by the US totaling more than 30 megatons of TNT took place during the cold war; in 1977–1980, a concrete dome (the Runit Dome) was built on Runit Island to deposit radioactive soil and debris.[4]

The Runit Dome is deteriorating and could be breached by a typhoon, though the sediments in the lagoon are even more radioactive than those which are contained.[5]

Enewetak Atoll - 2014-02-10 - Landsat 8 - 15m
Landsat 8 satellite image of Enewetak Atoll. The crater formed by the Ivy Mike nuclear test can be seen near the north cape of the atoll, with the smaller Castle Nectar crater adjoining it.
Enewetak is located in Marshall Islands
LocationNorth Pacific
Coordinates11°30′N 162°20′E / 11.500°N 162.333°ECoordinates: 11°30′N 162°20′E / 11.500°N 162.333°E
Total islands40
Area5.85 km2 (2.26 sq mi)[1]
Highest elevation5 m (16 ft)
Population664 (2011)[1]
Ethnic groupsMarshallese
Enewetak map
Map of Enewetak Atoll
Enewetak or Eniwetok atoll
Aerial view of Enewetak and Parry


The U.S. government referred to the atoll as "Eniwetok" until 1974, when it changed its official spelling to "Enewetak" (along with many other Marshall Islands place names, to more properly reflect their pronunciation by the Marshall Islanders[6]).


Enewetak Atoll formed atop a seamount. The seamount was formed in the late Cretaceous.[7] This seamount is now about 1,400 metres (4,600 ft) below sea level.[8] It is made of basalt, and its depth is due to a general subsidence of the entire region and not because of erosion.[9]

Enewetak has a mean elevation above sea level of 3 metres (9.8 ft).[10]


Humans have inhabited the atoll since about 1,000 B.C.[11]

The first European visitor to Enewetak, Spanish explorer Alvaro de Saavedra, arrived on 10 October 1529.[12][13] He called the island "Los Jardines" (The Gardens). In 1794 sailors aboard the British merchant sloop Walpole called the islands "Brown's Range" (thus the Japanese name "Brown Atoll"). It was visited by about a dozen ships before the establishment of the German colony of the Marshall Islands in 1885. With the rest of the Marshalls, Enewetak was captured by the Imperial Japanese Navy in 1914 during World War I and mandated to the Empire of Japan by the League of Nations in 1920. The Japanese administered the island under the South Pacific Mandate, but mostly left affairs in hands of traditional local leaders until the start of World War II. The atoll, together with other part of Marshall Islands located to the west of 164°E, was placed under the governance of Pohnpei district during the Japanese administration period, and is different from rest of Marshall Islands.[14]

In November 1942, the Japanese built an airfield on Engebi Island. As they used it only for refueling planes between Truk and islands to the east, no aviation personnel were stationed there and the island had only token defenses. When the Gilberts fell to the United States, the Imperial Japanese Army assigned defense of the atoll to the 1st Amphibious Brigade, formed from the 3rd Independent Garrison, which had previously been stationed in Manchukuo. The 1st Amphibious Brigade arrived on January 4, 1944. Some 2,586 of its 3,940 men were left to defend Eniwetok Atoll, supplemented by aviation personnel, civilian employees, and laborers. However, they were unable to finish the fortifications before the American attack came in February. During the ensuing Battle of Eniwetok, the Americans captured Enewetak in a five-day amphibious operation. Fighting mainly took place on Engebi Islet, site of the most important Japanese installation, although some combat occurred on the main islet of Enewetak itself and on Parry Island, where there was a Japanese seaplane base.

Following its capture, the anchorage at Enewetak became a major forward base for the U.S. Navy. The daily average of ships present during the first half of July 1944 was 488; during the second half of July the daily average number of ships at Enewetak was 283.[15]

In 1950, John C. Woods, who executed the Nazi war criminals convicted at the Nuremberg Trials, was accidentally electrocuted here.

After the end of World War II, Enewetak came under the control of the United States as part of the Trust Territory of the Pacific Islands until the independence of the Marshall Islands in 1986. During its tenure, the United States evacuated the local residents many times, often involuntarily. The atoll was used for nuclear testing as part of the Pacific Proving Grounds. Before testing commenced, the U.S. exhumed the bodies of United States servicemen killed in the Battle of Enewetak and returned them to the United States to be re-buried by their families. Forty-three nuclear tests were fired at Enewetak from 1948 to 1958.[16]

The first hydrogen bomb test, code-named Ivy Mike, occurred in late 1952 as part of Operation Ivy; it vaporized the islet of Elugelab. This test included B-17 Flying Fortress drones to fly through the radioactive cloud to test onboard samples. B-17 mother ships controlled the drones while flying within visual distance of them. In all 16 to 20 B-17s took part in this operation, of which half were controlling aircraft and half were drones. To examine the explosion clouds of the nuclear bombs in 1957/58 several rockets (mostly from rockoons) were launched. One USAF airman was lost at sea during the tests.

Runit Dome 001
Aerial view of the Runit Dome. The dome is placed in the crater created by the "Cactus" nuclear weapons test in 1958.

A radiological survey of Enewetak was conducted from 1972 to 1973.[17] In 1977, the United States military began decontamination of Enewetak and other islands. During the three-year, US$100 million cleanup process, the military mixed more than 80,000 cubic metres (100,000 cu yd) of contaminated soil and debris[18] from the islands with Portland cement and buried it in an atomic blast crater on the northern end of the atoll's Runit Island.[19][20] The material was placed in the 9.1-metre (30 ft) deep, 110-metre (360 ft) wide crater created by the May 5, 1958, "Cactus" nuclear weapons test. A dome composed of 358 concrete panels, each 46 centimetres (18 in) thick, was constructed over the material. The final cost of the cleanup project was US$239 million.[18] The United States government declared the southern and western islands in the atoll safe for habitation in 1980,[21] and residents of Enewetak returned that same year.[22] The military members who participated in that cleanup mission are suffering from many health issues, but the U.S. Government is refusing to provide health coverage. [23]

Section 177 of the 1983 Compact of Free Association between the governments of the United States and the Marshall Islands[24] establishes a process for Marshallese to make a claim against the United States government as a result of damage and injury caused by nuclear testing. That same year, an agreement was signed to implement Section 177 which established a US$150 million trust fund. The fund was intended to generate US$18 million a year, which would be payable to claimants on an agreed-upon schedule. If the US$18 million a year generated by the fund was not enough to cover claims, the principal of the fund could be used.[25][26] A Marshall Islands Nuclear Claims Tribunal was established to adjudicate claims. In 2000, the tribunal made a compensation award to the people of Enewetak consisting of US$107.8 million for environmental restoration; US$244 million in damages to cover economic losses caused by loss of access and use of the atoll; and US$34 million for hardship and suffering.[26] In addition, as of the end of 2008, another US$96.658 million in individual damage awards were made. Only US$73.526 million of the individual claims award has been paid, however, and no new awards were made between the end of 2008 and May 2010.[26] Due to stock market losses, payments rates that have outstripped fund income, and other issues, the fund was nearly exhausted as of May 2010 and unable to make any additional awards or payments.[26] A lawsuit by Marshallese arguing that "changed circumstances" made Nuclear Claims Tribunal unable to make just compensation was dismissed by the Supreme Court of the United States in April 2010.[27]

The 2000 environmental restoration award included funds for additional cleanup of radioactivity on Enewetak. Rather than scrape the topsoil off, replace it with clean topsoil, and create another radioactive waste repository dome at some site on the atoll (a project estimated to cost US$947 million), most areas still contaminated on Enewetak were treated with potassium.[28] Soil that could not be effectively treated for human use was removed and used as fill for a causeway connecting the two main islands of the atoll (Enewetak and Parry). The cost of the potassium decontamination project was US$103.3 million.[26]

It is projected that the majority of the atoll will be fit for human habitation by the year 2026–2027 after nuclear decay, de-contamination and environmental remediation efforts create sufficient dose reductions.[29] However, in November 2017, the Australian Broadcasting Corporation reported that rising sea levels caused by climate change are seeping inside the dome, causing radioactive material to leak out.[30]


Marshall Islands Public School System operates Enewetak Elementary School.[31] Marshall Islands High School on Majuro serves the community.[32]

Eniwetok Airfield

Men from the 110th Naval Construction Battalion arrived on Eniwetok between 21 and 27 February 1944 and began clearing the island for construction of a bomber airfield. A 2,100-metre (6,900 ft) by 120-metre (390 ft) runway with taxiways and supporting facilities was built. The first plane landed on 11 March. By 5 April the first operational bombing mission was conducted.[33] The base was later named for Lieutenant John H. Stickell.[34][35]

In mid-September 1944 operations at Wrigley Airfield on Engebi Island were transferred to Eniwetok.[36]

US Navy and Marine units based at Eniwetok included:

  • VB-102 operating PB4Y-1s from 12–27 August 1944[37]
  • VB-108 operating PB4Y-1s from 11 April-10 July 1944[38]
  • VB-109 operating PB4Y-1s from 5 April-14 August 1944[39]
  • VB-116 operating PB4Y-1s from 7 July-27 August 1944[40]
  • VPB-121 operating PB4Y-1s from 1 March-3 July 1945[41]
  • VPB-144 operating PV-2s from 27 June 1945 until September 1946[42]

The airstrip is now abandoned and its surface partially covered by sand.

Parry Island seaplane base

The Imperial Japanese Navy had developed a seaplane base on Parry Island. Following its capture on 22 February, Seebees from the 110th Naval Construction Battalion expanded the base, building a coral-surfaced parking area and shops for minor aircraft and engine overhaul. A marine ways was installed on a Japanese pier and boat-repair shops were also erected.[33]

US Navy and Marine units based at Parry Island included:

  • VP-13 operating PB2Y-3s from 26 February-22 June 1944[43]
  • VP-16 operating PBM-3Ds from 7 June-1 August 1944[43]
  • VP-21 operating PBM-3Ds from 19 August-17 October 1944 and from 15 July-11 September 1945[44]
  • VP-23 operating PBY-5As from 20 August 1944 – 9 April 1945[45]
  • VP-MS-6 operating PBM-5Es from 1 February 1948 in support of Operation Sandstone[46]
  • VP-102 operating PB2Y-3s from 3 February-30 August 1944[47]
  • VP-202 operating PBM-3Ds from 24 February-1 March 1944[48]
  • VPB-19 operating PBM-3Ds from 2 November 1944 – 12 February 1945 and 6 March 1945-January 1946[49]
  • VPB-22 operating PBM-3Ds from 10 October-30 November 1944 and from 25 June-7 August 1945[50]

List of nuclear tests at Eniwetok


Nuclear Tests on and around Enewetak Atoll
Series Start Date End Date Count Yield Range Total Yield
Sandstone 14 April 1948 14 May 1948 3 18 - 49 kilotons 104 kilotons
Greenhouse 7 April 1951 4 May 1951 4 45.5-225 kilotons 396.5 kilotons
Ivy 31 October 1952 15 November 1952 2 500 kilotons - 10.4 megatons 10.9 megatons
Operation Castle 13 May 1954 13 May 1954 1 1.69 megaton 1.69 megaton
Redwing 4 May 1956 21 July 1956 11 190 tons - 1.9 megatons ~2.61 megatons
Hardtack I 5 April 1958 18 August 1958 22 Zero - 8.9 megatons 16.1 megatons
Total     43[29]   Approx 31.8 megatons (almost 6% of total test yield worldwide)

Operation Sandstone

Test shot Date Location Yield
X-Ray 18:17 14 April 1948 (GMT) Enjebi Islet 37 kt
Yoke 18:09 30 April 1948 (GMT) Aomon Islet 49 kt
Zebra 18:04 14 May 1948 (GMT) Runit Islet 18 kt

Operation Greenhouse

test shot Date Location Yield
Dog 18:34 7 April 1951 (GMT) Runit Islet 81 kt
Easy 18:26 20 April 1951 (GMT) Enjebi Islet 47 kt
George 21:30 8 May 1951 (GMT) Eberiru Islet 225 kt
Item 18:17 24 May 1951 (GMT) Enjebi Islet 45.5 kt

Operation Ivy

Test shot Date Location Yield
Mike 19:14:59.4 31 October 1952 (GMT) Elugelab Islet 10.4 Mt
King 23:30 15 November 1952 (GMT) Runit Islet 500 kt

Operation Castle

Test shot Date Location Yield
Nectar 18:00 13 May 1954 UTC Off Bogon Islet near Ivy Mike crater 1.69 Mt

Operation Redwing

Test shot Date Location Yield
Lacrosse 18:25 4 May 1956 (GMT) Runit Islet 40 kt
Yuma 19:56 27 May 1956 (GMT) Aomon Islet 0.19 kt
Erie 18:15 30 May 1956 (GMT) Runit Islet 14.9 kt
Seminole 00:55 6 June 1956 (GMT) Bogon Islet 13.7 kt
Blackfoot 18:26 11 June 1956 (GMT) Runit Islet 8 kt
Kickapoo 23:26 13 June 1956 (GMT) Aomon Islet 1.49 kt
Osage 01:14 16 June 1956 (GMT) Runit Islet 1.7 kt
Inca 21:26 21 June 1956 (GMT) Rujoru Islet 15.2 kt
Mohawk 18:06 2 July 1956 (GMT) Eberiru Islet 360 kt
Apache 18:06 8 July 1956 (GMT) near Ivy Mike crater 1.9 Mt
Huron 18:12 21 July 1956 (GMT) Off Flora Islet 250 kt

Operation Hardtack I

on —

Test shot Date Location Yield
Yucca 18:15 28 April 1958 (GMT) 157 km N of Eniwetok-Atoll 1.7 kt
Cactus 18:15 5 May 1958 (GMT) Runit Islet 18 kt
Butternut 18:15 11 May 1958 (GMT) Eniwetok-Atoll 81 kt
Koa 18:30 12 May 1958 (GMT) Eniwetok-Atoll 1370 kt
Wahoo 01:30 16 May 1958 (GMT) Eniwetok-Atoll 9 kt
Holly 18:30 20 May 1958 (GMT) Eniwetok-Atoll 5.9 kt
Yellowwood 2:00 26 May 1958 (GMT) Eniwetok Lagoon 330 kt
Magnolia 18:00 26 May 1958 (GMT) Eniwetok-Atoll 57 kt
Tobacco 02:50 30 May 1958 (GMT) Eniwetok-Atoll 11.6 kt
Rose 18:45 2 June 1958 (GMT) Eniwetok-Atoll 15 kt
Umbrella 23:15 8 June 1958 (GMT) Eniwetok Lagoon 8 kt
Walnut 18:30 14 June 1958 (GMT) Eniwetok-Atoll 1.45 kt
Linden 03:00 18 June 1958 (GMT) Eniwetok-Atoll 11 kt
Elder 18:30 27 June 1958 (GMT) Eniwetok-Atoll 880 kt
Oak 19:30 28 June 1958 (GMT) Eniwetok Lagoon 8.9 Mt
Sequoia 18:30 1 July 1958 (GMT) Eniwetok-Atoll 5.2 kt
Dogwood 18:30 5 July 1958 (GMT) Eniwetok-Atoll 397 kt
Scaevola 04:00 14 July 1958 (GMT) Eniwetok-Atoll 0 kt
Pisonia 23:00 17 July 1958 (GMT) Eniwetok-Atoll 255 kt
Olive 18:15 22 July 1958 (GMT) Eniwetok-Atoll 202 kt
Pine 20:30 26 July 1958 (GMT) Eniwetok-Atoll 2000 kt
Quince 02:15 6 August 1958 (GMT) Eniwetok-Atoll 0 kt
Fig 04:00 18 August 1958 (GMT) Eniwetok-Atoll 0.02 kt


Eroberung von Eniwetok

Battle of Eniwetok

Boeing B-17 drone at Eniwetok 1948

B-17 drone at Eniwetok Airfield in 1948 for Operation Sandstone


Operation Sandstone

Ivy Mike (Eniwetok-Atoll - 31. Oktober 1952)

Ivy Mike test, October 31, 1952

Atombombentest Greenhouse-George

Operation Greenhouse test

Ivy King - mushroom cloud

Ivy King test, November 1952

Atombombentest Redwing-Seminole 01

Test shot Seminole of Operation Redwing, conducted on the coast of the island of Bogon

Atombombentest Redwing-Seminole 02

Red-wing Seminole test

Hardtack Umbrella nuke

Hardtack Umbrella test

Video clips of three test nuclear explosions in Eniwetok, Marshall Islands

Test shot Nectar of Operation Castle produced a yield of 1.69 megatons and was detonated just north east of Ivy Mike's Elugelab crater. The Island of Bogon is the spearhead shaped object at the bottom right of the screen, as it was before the Redwing Seminole test was conducted on that island.


  1. ^ a b c d Brinkhoff, Thomas (2012-07-19). "Marshall Islands". City Population. Retrieved 2019-01-30.
  2. ^ "Eniwetok". Oxford Dictionaries. Oxford University Press.
  3. ^ "Marshallese-English Dictionary - Place Name Index". www.trussel2.com.
  4. ^ "Enewetak Atoll – nuclear trash can of the pacific – UTAOT". www.utaot.com.
  5. ^ A Pacific isle radioactive and forgotten, The New York Times, Michael B. Gerrard, December 3, 2014. Retrieved 19 September 2016.
  6. ^ Hacker, Barton C. (1994). Elements of controversy : the Atomic Energy Commission and radiation safety in nuclear weapons testing, 1947–1974. Berkeley, CA: University of California Press. p. 14. ISBN 0520083237.
  7. ^ Clouard, Valerie; Bonneville, Alain (2005). "Ages of Seamounts, Islands and Plateaus on the Pacific Plate". In Foulger, Gillian R.; Natland, James H.; Presnall, Dean C.; et al. Plates, Plumes, and Paradigms. Boulder, Colo.: Geological Society of America. pp. 71–90 [p. 80]. ISBN 0813723884.
  8. ^ Ludwig, K. R.; Halley, R. B.; Simmons, K. R.; Peterman, Z. E. (1988). "Strontium-Isotope Stratigraphy of Enewetak Atoll". Geology. 16 (2): 173–177 [p. 173–174]. doi:10.1130/0091-7613(1988)016<0173:SISOEA>2.3.CO;2.
  9. ^ Schlanger, S. O.; Campbell, J. F.; Jackson, M. W. (1987). "Post-Eocene subsidence of the Marshall Islands Recorded By Drowned Atolls on Harrie and Sylvania Guyots". In Keating, B. H.; et al. Seamounts, Islands, and Atolls. Geophysical Monograph Series. 43. Washington, D.C.: American Geophysical Union. pp. 165–174 [p. 173]. ISBN 0875900682.
  10. ^ Munk, Walter; Day, Deborah (2004). "Ivy-Mike". Oceanography. 17 (2): 97–105 [p. 98]. doi:10.5670/oceanog.2004.53.
  11. ^ Hezel 1983, p. 3.
  12. ^ Hezel 1983, p. 16-17.
  13. ^ Brand, Donald D. The Pacific Basin: A History of its Geographical Explorations The American Geographical Society, New York, 1967, p.122
  14. ^ "昔はサイパンもパラオも「日本」だった ── 日本の南洋群島統治". teikoku-denmo.jp.
  15. ^ Carter, Worrall Reed. Beans, Bullets, and Black Oil: The Story of Fleet Logistics Afloat in the Pacific During World War II. Washington, D.C.: Department of the Navy, 1953, p. 163.
  16. ^ Diehl, Sarah and Moltz, James Clay. Nuclear Weapons and Nonproliferation: A Reference Book. Santa Barbara, Calif.: ABC-CLIO, 2002, p. 208.
  17. ^ Johnson, Giff. "Paradise Lost." Bulletin of the Atomic Scientists. December 1980, p. 27.
  18. ^ a b Schwartz, Stephen I. Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940. Washington, D.C.: Brookings Institution Press, 1998, p. 380.
  19. ^ Johnson, Bulletin of the Atomic Scientists, p. 24.
  20. ^ A 15 kiloton nuclear weapon exploded but did not undergo nuclear fission on Runit, scattering plutonium over the island. Runit Island is not habitable for the next 24,000 years, which is why it was chosen for the nuclear waste repository. See: Wargo, John. Green Intelligence: Creating Environments That Protect Human Health. New Haven, Conn.: Yale University Press, 2009, p. 15.
  21. ^ The government said that the northern islands would not be safe for inhabitation until 2010. See: Johnson, Bulletin of the Atomic Scientists, p. 25.
  22. ^ Linsley, Gordon. "Site Restoration and Cleanup of Contaminated Areas." In Current Trends in Radiation Protection: On the Occasion of the 11th International Congress of the International Radiation Protection Association, 23–28 May 2004, Madrid, Spain. Henri Métivier, Leopoldo Arranz, Eduardo Gallego, and Annie Sugier, eds. Les Ulis: EDP Sciences, 2004, p. 142.
  23. ^ Philipps, Dave (Jan 28, 2017). "Troops Who Cleaned Up Radioactive Islands Can't Get Medical Care". The New York Times.
  24. ^ The Compact was ratified by both nations in 1986.
  25. ^ Louka, Elli. Nuclear Weapons, Justice and the Law. Northampton, Mass.: Edward Elgar, 2011, p. 161-162.
  26. ^ a b c d e Graham, Bill. "Written Testimony of Bill Graham, Public Advocate (retired), Marshall Islands Nuclear Claims Tribunal." Subcommittee on Asia, the Pacific, and the Global Environment. Committee on Foreign Affairs. United States House of Representatives. May 20, 2010. Accessed 2012-11-01.
  27. ^ Richey, Warren (April 5, 2010). "Supreme Court: No Review of Award for US Nuclear Weapons Tests". Christian Science Monitor.
  28. ^ Cesium, which is highly radioactive, is chemically similar to potassium. Since the atoll is deficient in potassium, plants absorb cesium from the ground instead. This makes the plants inedible. Cesium also is deposited in the muscles of the human body, just as potassium is. See: Firth, Stewart (1987). Nuclear Playground. Honolulu: University of Hawaii Press. p. 36. ISBN 0824811445.
  29. ^ a b "Loss-of-Damages From U.S. Nuclear Testing in the Marshall Islands: Technical Analysis of the Nuclear Claims Tribunal Methodology and Alternative Estimate" (PDF).
  30. ^ Willacy, Mark (November 27, 2017). "A poison in tour island". ABC. Retrieved November 27, 2017.
  31. ^ "Public Schools ." Marshall Islands Public School System. Retrieved on February 21, 2018.
  32. ^ "Annual Report 2011-2012." Ministry of Education (Marshall Islands). Retrieved on February 22, 2018. p. 54 (PDF p. 55/118). "Marshall Islands High Schools [sic] takes students from Ratak Rak zone including schools in Majuro, Arno, Mili, and Enewetak/Mejatto."
  33. ^ a b Bureau of Yards and Docks 1947, p. 325.
  34. ^ Carey, Alan (1999). The Reluctant Raiders: The Story of United States Navy Bombing Squadron VB/VPB-109 During World War II. Schiffer Publishing. p. 64. ISBN 9780764307577.
  35. ^ Morison, Samuel (1975). History of United States Naval Operations in World War II. Volume VI: Aleutians, Gilberts and Marshalls, June 1942-April 1944. U.S. Government Printing Office. p. 306.
  36. ^ Bureau of Yards and Docks 1947, p. 326.
  37. ^ Roberts 2000, p. 135.
  38. ^ Roberts 2000, p. 186.
  39. ^ Roberts 2000, p. 522-3.
  40. ^ Roberts 2000, p. 623.
  41. ^ Roberts 2000, p. 544.
  42. ^ Roberts 2000, p. 35.
  43. ^ a b Roberts 2000, p. 410.
  44. ^ Roberts 2000, pp. 233-4.
  45. ^ Roberts 2000, p. 431.
  46. ^ Roberts 2000, p. 267.
  47. ^ Roberts 2000, p. 392.
  48. ^ Roberts 2000, p. 591.
  49. ^ Roberts 2000, p. 295.
  50. ^ Roberts 2000, p. 236.


External links

 This article incorporates public domain material from the Air Force Historical Research Agency website http://www.afhra.af.mil/.

Battle of Eniwetok

The Battle of Eniwetok was a battle of the Pacific campaign of World War II, fought between 17 February 1944 and 23 February 1944, on Enewetok Atoll in the Marshall Islands. The invasion of Eniwetok followed the American success in the Battle of Kwajalein to the southeast. Capture of Eniwetok would provide an airfield and harbor to support attacks on the Mariana Islands to the northwest. The operation was officially known as "Operation Catchpole", and was a three-phase operation involving the invasion of the three main islands in the Eniwetok Atoll.

Vice Admiral Raymond Spruance preceded the invasion with Operation Hailstone, a carrier strike against the Japanese base at Truk in the Caroline Islands. This raid destroyed 39 warships and more than 200 planes.


Elugelab, or Elugelap (Marshallese: Āllokļap, [æ̯ælʲlʲe͡oɡʷ(ɔ͡ʌ)ɫɑ͡æpʲ]), was an island, part of the Enewetak Atoll in the Marshall Islands. It was increased in size, and then destroyed by the world's first true hydrogen bomb test on 1 November 1952, a test which was codenamed shot "Mike" of Operation Ivy. Prior to being enlarged, and destroyed, the island was described as "just another small naked island of the atoll".The fireball created by Ivy Mike had a maximum radius of 2.9 to 3.28 km (1.80 to 2.04 mi). This maximum is reached a number of seconds after the detonation and during this time the hot fireball invariably rises due to buoyancy. While still relatively close to the ground, the fireball had yet to reach its maximum dimensions and was thus approximately "three and one quarter" miles (5.2 km) wide.The detonation produced a crater 6,240 feet (1.90 km) in diameter and 164 feet (50 m) deep where Elugelab had once been; the blast and water waves from the explosion (some waves up to twenty feet high) stripped the test islands clean of vegetation, as observed by a helicopter survey within 60 minutes after the test, by which time the mushroom cloud had blown away. The island "became dust and ash, pulled upward to form a mushroom cloud that rose about twenty-seven miles into the sky. According to Eric Schlosser, all that remained of Elugelab was a circular crater filled with seawater, more than a mile in diameter and "fifteen storeys deep". The blast yielded 10.4 megatons of explosive energy, 700 times the energy that leveled central Hiroshima.Aerial footage of Elugelab and adjacent islands well before Mike shot at a time prior to the connecting causeway being created is available, as is footage after the causeway was finished that supported the diagnostic Krause-Ogle box light pipe system, with numerous trees removed in preparation of the shot also plainly evident, along with footage of the aforementioned helicopter survey of the Mike crater soon after the detonation, and finally, high-altitude footage of the crater accompanied with details of its depth—"175 feet deep"—equivalent to the height of a "17-storey building" and with an area large enough to accommodate about "14 Pentagon buildings".The detonation also collapsed some natural crevices in the reef, some distance away from the rim of the crater.Full radioecology recovery surveys were documented before and after each test series. For a brief online introduction into some of these studies—with specific reference to the ecological effects of the 1.69-megaton Operation Castle Nectar shot, detonated in 1954 on a barge just north east of the crater of the 10.4-megaton Ivy Mike thermonuclear test - see [1] a report by the University of Washington's Laboratory of Radiation Biology and [2].

Enewetak Auxiliary Airfield

Enewetak Auxiliary Airfield is a private airport at Enewetak on Enewetak Atoll, Marshall Islands. This airport is assigned the location identifier ENT by the IATA.

Ernst Henry Krause

Dr Ernst H. Krause (2 May 1913 in Milwaukee, WI – 23 August 1989 in Newport Beach, CA) was an American nuclear physicist and aerospace executive. He participated in early radar and rocketry research at the Naval Research Laboratory as a member of the Upper Atmosphere Research Panel, working with Milton Rosen. His body of work includes experiments studying the upper atmosphere after World War II using captured V-2 rockets. From 1947 to 1951 he was involved in the first atomic testing at Enewetak Atoll in the Pacific, and later worked at the Lockheed Missiles and Space Company. In 1955 he started the Systems Research Corporation, which later became Ford Aerospace.

Greenhouse Item

Greenhouse Item was an American nuclear test conducted on May 25, 1951, as part of Operation Greenhouse at the Pacific Proving Ground, specifically on the island of Engebi in the Eniwetok Atoll in the Central Pacific Ocean. This test explosion was the first test of a boosted fission weapon.

Ivy King

Ivy King was the largest pure-fission nuclear bomb ever tested by the United States. The bomb was tested during the Truman administration as part of Operation Ivy. This series of tests involved the development of very powerful nuclear weapons in response to the nuclear weapons program of the Soviet Union.

The production of Ivy King was hurried to be ready in case its sister project, Ivy Mike, failed in its attempt to achieve a thermonuclear reaction. The Ivy King test actually took place two weeks after Mike. Unlike the Mike bomb, the Ivy King device could theoretically have been added to United States' nuclear arsenal because it was designed to be air-deliverable.

On November 16, 1952 at 11:30 local time (23:30 GMT) a B-36H bomber dropped the bomb over a point 2,000 feet (610 m) north of Runit Island in the Enewetak atoll, resulting in a 500 kiloton explosion at 1,480 feet (450 m). The tropopause height at the time of the detonation was about 58,000 feet (18 km). The top of the King cloud reached about 74,000 feet (23 km) with the mushroom base at about 40,000 feet (12 km).The Ivy King bomb, designated as a Mk-18 bomb and named the "Super Oralloy Bomb", was a modified version of the Mk-6D bomb. Instead of using an implosion system similar to the Mk-6D, it used a 92-point implosion system initially developed for the Mk-13. Its uranium-plutonium core was replaced by 60 kg of highly enriched uranium (HEU) fashioned into a thin-walled sphere equivalent to approximately four critical masses. The thin-walled sphere was a commonly used design, which ensured that the fissile material remained sub-critical until imploded. The HEU sphere was then enclosed in a natural-uranium neutron reflector. To physically prevent the HEU sphere collapsing into a critical condition if the surrounding explosives were detonated accidentally, or if the sphere was crushed following an aircraft accident, the hollow center was filled with a chain made from aluminum and boron, which was pulled out to arm the bomb. The boron-coated chain also absorbed the neutrons needed to drive the nuclear reaction.The primary designer of the Super Oralloy Bomb, physicist Ted Taylor, later became a vocal proponent of nuclear disarmament.

Ivy Mike

Ivy Mike was the codename given to the first test of a full-scale thermonuclear device, in which part of the explosive yield comes from nuclear fusion. It was detonated on November 1, 1952 by the United States on the island of Elugelab in Enewetak Atoll, in the Pacific Ocean, as part of Operation Ivy. It was the first full test of the Teller–Ulam design, a staged fusion device.

Due to its physical size and fusion fuel type (cryogenic liquid deuterium), the Mike device was not suitable for use as a deliverable weapon; it was intended as an extremely conservative proof of concept experiment to validate the concepts used for multi-megaton detonations. A simplified and lightened bomb version (the EC-16) was prepared and scheduled to be tested in operation Castle Yankee, as a backup in case the non-cryogenic "Shrimp" fusion device (tested in Castle Bravo) failed to work; that test was cancelled when the Bravo device was tested successfully, making the cryogenic designs obsolete.

Mark 18 nuclear bomb

The Mark 18 nuclear bomb, also known as the SOB or Super Oralloy Bomb, was an American nuclear bomb design which was the highest yield fission bomb produced by the US. The Mark 18 had a design yield of 500 kilotons. Noted nuclear weapon designer Ted Taylor was the lead designer for the Mark 18.

The Mark 18 was tested once, in the Ivy King nuclear test at the Enewetak atoll in the Pacific Ocean. The test was a complete success at full yield.

Mid-Pacific Research Laboratory

The Mid-Pacific Research Laboratory was a marine research facility located in a former US Coast Guard LORAN station on the northern tip of Enewetak Island, part of the Enewetak Atoll in the Marshall Islands. It was opened in 1952, when it was called the Eniwetok Marine Biological Laboratory, on the island of Medren and in the early part of its operation it was typically staffed and active when nuclear testing by the United States was being carried out. In the years following the ending of nuclear testing in 1958 the facility was moved to Enewetak Island and it was still staffed for only part of the year until in 1974 it gained full-time research staff. In 1979 its name was changed to the Mid-Pacific Research Laboratory. Research carried out at the lab included studies on energy relationships, symbiosis, colonization of the land by marine organisms, metabolic adaptations of marine organisms and taxonomy. The lab was funded by the University of Hawaii and the US Department of Energy The laboratory was closed down after the Department of Energy ceased funding in 1983, although research was still carried out for some years afterwards with alternative sponsorships.

Operation Castle

Operation Castle was a United States series of high-yield (high-energy) nuclear tests by Joint Task Force 7 (JTF-7) at Bikini Atoll beginning in March 1954. It followed Operation Upshot–Knothole and preceded Operation Teapot.

Conducted as a joint venture between the Atomic Energy Commission (AEC) and the Department of Defense (DoD), the ultimate objective of the operation was to test designs for an aircraft-deliverable thermonuclear weapon.

Operation Castle was considered by government officials to be a success as it proved the feasibility of deployable "dry" fuel designs for thermonuclear weapons. There were technical difficulties with some of the tests: one device had a yield much lower than predicted (a "fizzle"), while two other bombs detonated with over twice their predicted yields. One test in particular, Castle Bravo, resulted in extensive radiological contamination of nearby islands (including inhabitants and U.S. soldiers stationed there), as well as a nearby Japanese fishing boat (the Daigo Fukuryū Maru), resulting in one direct fatality, and then continued health problems for many of those exposed. Public reaction to the tests and an awareness of the long-range effects of nuclear fallout has been attributed as being part of the motivation for the Partial Test Ban Treaty of 1963.

Operation Greenhouse

Operation Greenhouse was the fifth American nuclear test series, the second conducted in 1951 and the first to test principles that would lead to developing thermonuclear weapons (hydrogen bombs). Conducted at the new Pacific Proving Ground, specifically on islands of the Enewetak Atoll, all of the devices were mounted in large steel towers, to simulate air bursts. This series of nuclear weapons tests was preceded by Operation Ranger and succeeded by Operation Buster-Jangle.

Operation Greenhouse showcased new and aggressive designs for nuclear weapons. The main idea was to reduce the size, weight, and most importantly, reduce the amount of fissile material necessary for nuclear weapons, while increasing the destructive power. With the Soviet Union's first nuclear test a year and half earlier, the United States had begun stockpiling the new designs before they were actually proven. Thus the success of Operation Greenhouse was vital before the development of thermonuclear weapons could continue.

A number of target buildings, including bunkers, houses and factories were built on Mujinkarikku Islet to test nuclear weapon effects.

Operation Hardtack I

Operation Hardtack I was a series of 35 nuclear tests conducted by the United States from April 28 to August 18 in 1958 at the Pacific Proving Grounds. At the time of testing, the Operation Hardtack I test series included more nuclear detonations than the total of all prior nuclear explosions in the Pacific Ocean. These tests followed the Project 58/58A series, which occurred from 1957 December 6 to 1958, March 14, and preceded the Operation Argus series, which took place in 1958 from August 27 to September 6.Operation Hardtack I was directed by Joint Task Force 7 (JTF 7). JTF-7 was a collaboration between the military and many civilians, but was structured like a military organization. Its 19,100 personnel were composed of members of the US military, Federal civilian employees, as well as workers affiliated with the Department of Defense (DOD) and the Atomic Energy Commission (AEC).There were three main research directions. The first was the development of new types of nuclear weapons. This was undertaken by detonating experimental devices created by the AEC's Los Alamos Scientific Laboratory and the University of California Radiation Laboratory. The DOD performed experiments and tests on these detonations that did not hamper the AEC's research. The second research direction was to examine how underwater explosions affected materiel, especially Navy ships, and was performed by the DOD. The tests were named Wahoo (open ocean) and Umbrella (lagoon); the former was conducted in the open ocean whereas the latter in a lagoon. The final avenue of study was to analyze high-altitude nuclear tests to refine the detection of high-altitude nuclear tests and investigate defensive practices for combatting ballistic missiles. This research direction was composed of three individual tests and were the first high altitude tests. The individual tests in the series were Orange, Teak, and Yucca. Orange and Teak were known collectively as Operation Newsreel and were rocket boosted. Yucca reached its altitude utilizing balloons.

Operation Ivy

Operation Ivy was the eighth series of American nuclear tests, coming after Tumbler-Snapper and before Upshot–Knothole. The two explosions were staged in late 1952 at Eniwetok Atoll in the Pacific Proving Ground in the Marshall Islands.

Operation Redwing

Operation Redwing was a United States series of 17 nuclear test detonations from May to July 1956. They were conducted at Bikini and Enewetak atolls by Joint Task Force 7 (JTF7). The entire operation followed Project 56 and preceded Project 57. The primary intention was to test new, second-generation thermonuclear weapons. Also tested were fission devices intended to be used as primaries for thermonuclear weapons, and small tactical weapons for air defense. Redwing demonstrated the first United States airdrop of a deliverable hydrogen bomb during test Cherokee. Because the yields for many tests at Operation Castle in 1954 were dramatically higher than predictions, Redwing was conducted using an "energy budget": There were limits to the total amount of energy released, and the amount of fission yield was also strictly controlled. Fission, primarily "fast" fission of the natural uranium tamper surrounding the fusion capsule, greatly increases the yield of thermonuclear devices, and constitutes the great majority of the fallout, as nuclear fusion is a relatively clean reaction.

All shots were named after various Native American tribes.

Operation Sandstone

Operation Sandstone was a series of nuclear weapon tests in 1948. It was the third series of American tests, following Trinity in 1945 and Crossroads in 1946, and preceding Ranger. Like the Crossroads tests, the Sandstone tests were carried out at the Pacific Proving Grounds, although at Enewetak Atoll rather than Bikini Atoll. They differed from Crossroads in that they were conducted by the Atomic Energy Commission, with the armed forces having only a supporting role. The purpose of the Sandstone tests was also different: they were primarily tests of new bomb designs rather than of the effects of nuclear weapons. Three tests were carried out in April and May 1948 by Joint Task Force 7, with a work force of 10,366 personnel, of whom 9,890 were military.

The successful testing of the new cores in the Operation Sandstone tests rendered every component of the old weapons obsolete. Even before the third test had been carried out, production of the old cores was halted, and all effort concentrated on the new Mark 4 nuclear bomb, which would become the first mass-produced nuclear weapon. More efficient use of fissionable material as a result of Operation Sandstone would increase the U.S. nuclear stockpile from 56 bombs in June 1948 to 169 in June 1949.

Pacific Proving Grounds

The Pacific Proving Grounds was the name given by the United States government to a number of sites in the Marshall Islands and a few other sites in the Pacific Ocean at which it conducted nuclear testing between 1946 and 1962. The U.S. tested a nuclear weapon (codenamed Able) on Bikini Atoll on June 30, 1946. This was followed by Baker on July 24, 1946.

On July 18, 1947, the United States secured an agreement with the United Nations to govern the islands of Micronesia as the Trust Territory of the Pacific Islands, a strategic trusteeship territory. This is the only such trusteeship ever granted by the United Nations. The Trust Territory comprised about 2,000 islands spread over 3,000,000 square miles (7,800,000 km2) of the North Pacific Ocean. Five days later, the United States Atomic Energy Commission established the Pacific Proving Grounds.The United States conducted 105 atmospheric and underwater (i.e., not underground) nuclear tests in the Pacific, many of which were of extremely high yield. While the Marshall Islands testing composed 14% of all U.S. tests, it composed nearly 80% of the total yields of those detonated by the U.S., with an estimated total yield of around 210 megatons, with the largest being the 15 Mt Castle Bravo shot of 1954 which spread considerable nuclear fallout on many of the islands, including several which were inhabited, and some that had not been evacuated.Many of the islands which were part of the Pacific Proving Grounds are still contaminated from the nuclear fallout, and many of those who were living on the islands at the time of testing have suffered from an increased incidence of various health problems. Through the Radiation Exposure Compensation Act of 1990, at least $759 million has been paid to Marshall Islanders as compensation for their exposure to U.S. nuclear testing. Following the Castle Bravo accident, the U.S. paid $15.3 million to Japan.Scientists have calculated that the residents of the Marshall Islands during their lifetimes will be diagnosed with an added 1.6% (with 90% uncertainty range 0.4% to 3.4%) cancers attributable to fallout-related radiation exposures. The cancers are the consequence of exposure to ionizing radiation from weapons test fallout deposited during the testing period (1948-1958) and from residual radioactive sources during the subsequent 12 years (1959-1970).

Parry Island

Parry Island or Islands may refer to:

Parry Island (Ontario), in Georgian Bay, Ontario, Canada, site of the Wasauksing First Nation Indian reserve

Parry Island (Pacific), part of Enewetak Atoll in the Pacific Ocean and a fighting theatre in World War II

Parry Island, former name of Philip Island (British Columbia)

Parry Islands, former name of the Queen Elizabeth Islands, Canada

Runit Island

Runit Island () is one of 40 islands of the Enewetak Atoll of the Marshall Islands in the Pacific Ocean.

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