The following is a useful collection of geophysical terms. Search through using the alphabetical shortcuts or the “Find” function in your web browser.


variable density log (VDL)

Also called 3-dimensional log; a log of the acoustic wave train that is recorded photographically, so that variations in darkness are related to the relative amplitude of the waves.

velocity panels
A set of stacked test sections with a progression of assumed normal-moveout velocities applied. A powerful method for determining velocities if distinct reflection events are present, as the reflections will be coherent where the velocities are correct and be degraded in appearance at higher or lower NMO velocities.
vertical plate

A standard model for electromagnetic geophysical theory. It is usually defined as thin conductive sheet, infinite in horizontal dimension and depth extent. See: thin sheet