Gravity anomalies

  • Gravity Anomalies
  • The Earth's gravity field is determined by how the material that makes up the Earth is distributed throughout the Earth. Because gravity changes over the surface of the Earth, the weight of an object changes along with it. One can define standard gravity as the value of gravity for a perfectly smooth 'idealized' Earth, and the gravity 'anomaly' is a measure of how actual gravity deviates from this standard. A map of gravity anomalies (usually expressed in units of milliGals) tends to highlight short wavelength features better than a map of the geoid.
Abstract from DBPedia
    A gravity anomaly is the difference between the observed acceleration of a planet's reaction to gravity and a value predicted from a model. A location with a positive anomaly exhibits more gravity than predicted, while a negative anomaly exhibits a lower value than predicted. The anomaly is the body or effect that causes the deviation from the "ideal" gravity model. Many data corrections must be made to the measured gravity value in order to extract the response of the local anomaly, or local geology, which is typically the goal of applied geophysics.

    重力異常(じゅうりょくいじょう、gravity anomaly)とは、重力の実測値(あるいは観測値)と、理論モデルから予測される値との差のことである。測地学、地球物理学の分野と、天文学、宇宙物理学の分野の双方で、上記の意味で同じ用語が使われているが、対象が異なるため概念もかなり異なる。


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