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__NOTOC__ The term ''ground zero'' (sometimes also known as surface zero〔(Military Dictionary - Terms Defined "Surface Zero" )〕 as distinguished from )〔(Military Dictionary - Terms Defined "Zero Point" ) Note: The zero point may be in the air, or on or beneath the surface of land or water, depending upon the type of burst, and it is thus to be distinguished from ground zero.〕 describes the point on the Earth's surface closest to a detonation.〔(Nuclear Matters: A Practical Guide, Appendix B )〕 In the case of an explosion above the ground, ''ground zero'' refers to the point on the ground directly below the detonation and is sometimes called the hypocenter. The term has often been associated with nuclear explosions and other large bombs, but is also used in relation to earthquakes, epidemics and other disasters to mark the point of the most severe damage or destruction. The term is often re-used for disasters that have a geographic or conceptual epicenter. ==Trinity, Hiroshima, and Nagasaki== The origins of the term "ground zero" began with the Manhattan Project and the atomic bombings of Hiroshima and Nagasaki. The Strategic Bombing Survey of the atomic attacks, released in June 1946, used the term liberally, defining it as: "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.'"〔(U. S. Strategic Bombing Survey: The Effects of the Atomic Bombings of Hiroshima and Nagasaki ). June 19, 1946. President's Secretary's File, Truman Papers. Page 5.〕 William Laurence, an embedded reporter with the Manhattan Project, reported that "Zero" was "the code name given to the spot chosen for the atomic bomb test" in 1945.〔William L. Laurence, ''Dawn over Zero'' (London: Museum Press, 1947), 4.〕 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ground zero」の詳細全文を読む スポンサード リンク
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