Editing Hypocenter (section)

==Trinity, Hiroshima and Nagasaki==
[[File:Hiroshima Damage Map.gif|right|thumb|In mapping the effects of an atomic bomb, such as on the city of [[Hiroshima]] here, concentric circles are drawn centered on the point below the detonation and numbered at radial distances of 1,000 feet (305 meters). This point below the detonation is called "Ground Zero".]]
[[File:Hiroshima-Hypocenter.jpg|upright|thumb|Monument marking the hypocenter, or ground zero, of the atomic bomb explosion over [[Hiroshima]].]]
The term "ground zero" originally referred to the hypocenter of the [[Trinity (nuclear test)|Trinity test]] in [[Jornada del Muerto|Jornada del Muerto desert]] near [[Socorro, New Mexico]], and the [[atomic bombings of Hiroshima and Nagasaki]] in [[Japan]]. The [[United States Strategic Bombing Survey]] of the atomic attacks, released in June 1946, used the term liberally, defining it as:

{{blockquote|For convenience, the term 'ground zero' will be used to designate the point on the ground directly beneath the point of detonation, or 'air zero.'<ref>[http://www.trumanlibrary.org/whistlestop/study_collections/bomb/large/documents/index.php?pagenumber=10&documentid=65&documentdate=1946-06-19&studycollectionid=abomb&groupid= U.S. Strategic Bombing Survey: The Effects of the Atomic Bombings of Hiroshima and Nagasaki] {{Webarchive|url=https://web.archive.org/web/20110607124802/http://www.trumanlibrary.org/whistlestop/study_collections/bomb/large/documents/index.php?pagenumber=10&documentid=65&documentdate=1946-06-19&studycollectionid=abomb&groupid= |date=2011-06-07 }}. June 19, 1946. President's Secretary's File, Truman Papers. Page 5.</ref>}}

[[William Laurence]], an [[embedded reporter]] with the [[Manhattan Project]], reported that "Zero" was "the code name given to the spot chosen for the [Trinity] test" in 1945.<ref>[[William L. Laurence]], ''Dawn over Zero'' (London: Museum Press, 1947), 4.</ref>

The ''[[Oxford English Dictionary]]'', citing the use of the term in a 1946 ''[[New York Times]]'' report on the destroyed city of [[Hiroshima]], defines ''ground zero'' as "that part of the ground situated immediately under an exploding bomb, especially an atomic one."
The term was military slang, used at the Trinity site where the weapon tower for the first [[nuclear weapon]] was at "point zero", and moved into general use very shortly after the end of [[World War II]]. At Hiroshima, the hypocenter of the attack was [[Shima Hospital]], approximately {{convert|800|ft|m|abbr=on}} away from the intended aiming point at [[Aioi Bridge]].