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upward continuation The use of one set of measurements of a potential field (usually gravity or magnetic) over one surface to determine the field at a higher surface. Upward continuation is relatively reliable, in that the field is continued into free space where there are no causative bodies to perturb the field further (unlike downward continuation). The method effectively attenuates high-wavenumber anomalies due to near-surface features, thus providing a powerful method for examining deeper structures. Upward continuation is used in gravity surveys to determine the nature of the regional gravity pattern over a large area; in magnetic surveys it is particularly useful in tying together aeromagnetic surveys made from different flying altitudes.