Editing Anisotropy (section)

===Geophysics and geology===
[[Seismic anisotropy]] is the variation of seismic wavespeed with direction. Seismic anisotropy is an indicator of long range order in a material, where features smaller than the seismic [[wavelength]] (e.g., crystals, cracks, pores, layers, or inclusions) have a dominant alignment. This alignment leads to a directional variation of [[elasticity (physics)|elasticity]] wavespeed. Measuring the effects of anisotropy in seismic data can provide important information about processes and mineralogy in the Earth; significant seismic anisotropy has been detected in the Earth's [[crust (geology)|crust]], [[mantle (geology)|mantle]], and [[Earth's inner core|inner core]].

[[Geological]] formations with distinct layers of [[sedimentary]] material can exhibit electrical anisotropy; [[electrical conductivity]] in one direction (e.g. parallel to a layer), is different from that in another (e.g. perpendicular to a layer). This property is used in the gas and [[oil exploration]] industry to identify [[hydrocarbon]]-bearing sands in sequences of [[sand]] and [[shale]]. Sand-bearing hydrocarbon assets have high [[resistivity]] (low conductivity), whereas shales have lower resistivity. [[Formation evaluation]] instruments measure this conductivity or resistivity, and the results are used to help find oil and gas in wells. The mechanical anisotropy measured for some of the sedimentary rocks like coal and shale can change with corresponding changes in their surface properties like sorption when gases are produced from the coal and shale reservoirs.<ref>{{cite journal |last1=Saurabh |first1=Suman |last2=Harpalani |first2=Satya |title=Anisotropy of coal at various scales and its variation with sorption |journal=International Journal of Coal Geology |date=2 January 2019 |volume=201 |pages=14–25 |doi=10.1016/j.coal.2018.11.008 |bibcode=2019IJCG..201...14S |s2cid=133624963}}</ref>

The [[hydraulic conductivity]] of [[aquifer]]s is often anisotropic for the same reason. When calculating groundwater flow to [[drainage|drains]]<ref>{{cite web |author=Oosterbaan, R. J. |year=1997 |title=The Energy Balance of Groundwater Flow Applied to Subsurface Drainage in Anisotropic Soils by Pipes or Ditches With Entrance Resistance |url=https://www.waterlog.info/pdf/enerart.pdf |url-status=live |archive-url=https://web.archive.org/web/20090219221547/http://www.waterlog.info/pdf/enerart.pdf |archive-date=19 February 2009}} The corresponding free EnDrain program can be downloaded from: [https://www.waterlog.info/endrain.htm].</ref> or to [[water well|wells]],<ref>{{cite web |author=Oosterbaan, R. J. |year=2002 |title=Subsurface Land Drainage By Tube Wells |url=https://www.waterlog.info/pdf/wellspac.pdf}} 9 pp. The corresponding free WellDrain program can be downloaded from: [https://www.waterlog.info/weldrain.htm]</ref> the difference between horizontal and vertical permeability must be taken into account; otherwise the results may be subject to error.

Most common rock-forming [[mineral]]s are anisotropic, including [[quartz]] and [[feldspar]]. Anisotropy in minerals is most reliably seen in their [[optical mineralogy|optical properties]]. An example of an isotropic mineral is [[garnet]].

Igneous rock like granite also shows the anisotropy due to the orientation of the minerals during the solidification process.<ref>{{Cite web |last=MAT |first=Mahmut |date=2018-04-19 |title=Granite {{!}} Properties, Formation, Composition, Uses » Geology Science |url=https://geologyscience.com/rocks/granite/ |access-date=2024-02-16 |website=Geology Science |language=en-US}}</ref>