Reference Work Entry

Structural Geology and Tectonics

Part of the series Encyclopedia of Earth Science pp 13-15

Apparent dip and the use of the travis apparent dip calculators

  • Russell B. Travis

Apparent dip is the dip that a tabular or plane geologic feature such as a bed, a fault, or a vein appears to have on a cross-section. For any given true dip, the magnitude of the apparent dip depends on the angle at which the cross-section intersects the strike of the plane. This angle is commonly called the directional angle. If it is 90°, the apparent dip equals the true dip; if it is 0°, the apparent dip is 0° and on the cross section the plane appears to be horizontal. Consequently, on cross-sections, most dips are apparent and are greater than 0° but less than the true dips.

Conventional methods of determining apparent dip require measurement of the directional angle, followed by reference to a table or graph. The Travis Apparent Dip Calculator permits the determination of apparent dip with a single measurement that requires no further reference.

The Travis Apparent Dip Calculator is a semicircular plastic instrument similar ...

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