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The Hubbert curve is an approximation of the production rate of a resource over time. It is a symmetric logistic distribution curve,〔 often confused with the "normal" gaussian function. It first appeared in "Nuclear Energy and the Fossil Fuels," geologist M. King Hubbert's 1956 presentation to the American Petroleum Institute, as an idealized symmetric curve, during his tenure at the Shell Oil Company. It has gained a high degree of popularity in the scientific community for predicting the depletion of various natural resources. The curve is the main component of Hubbert peak theory, which has led to the rise of peak oil concerns. Basing his calculations on the peak of oil well discovery in 1948, Hubbert used his model in 1956 to create a curve which accurately predicted that oil production in the contiguous United States would peak around 1970.〔 ==Shape== The prototypical Hubbert curve is a probability density function of a logistic distribution curve. It is not a gaussian function (which is used to plot normal distributions), but the two have a similar appearance. The density of a Hubbert curve approaches zero more slowly than a gaussian function: : The graph of a Hubbert curve consists of three key elements: # a gradual rise from zero resource production that then increases quickly # a "Hubbert peak", representing the maximum production level # a drop from the peak that then follows a steep production decline. The actual shape of a graph of real world production trends is determined by various factors, such as development of enhanced production techniques, availability of competing resources, and government regulations on production or consumption. Because of such factors, real world Hubbert curves are often not symmetrical. 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「Hubbert curve」の詳細全文を読む スポンサード リンク
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