1. n. [Geophysics, Shale Gas, Geology]

Predictable variation of a property of a material with the direction in which it is measured, which can occur at all scales. For a crystal of a mineral, variation in physical properties observed in different directions is anisotropy. In rocks, variation in seismic velocity measured parallel or perpendicular to bedding surfaces is a form of anisotropy. Often found where platy minerals such as micas and clays align parallel to depositional bedding as sediments are compacted, anisotropy is common in shales.

Synonyms: aeolotropy

Antonyms: isotropy

See related terms: anisotropic,  anisotropic formation,  birefringence,  extensive dilatancy anisotropy,  heterogeneous formation,  raypath,  seismic velocity,  velocity