Preliminary reference Earth model: Difference between revisions

Revision as of 19:30, 28 December 2020

Revision as of 12:58, 6 August 2022

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{{Short description|Model representing the average Earth properties as a function of planetary radius}}

[[File:EarthGravityPREM.jpg|thumb|Earth's Gravity according to PREM. Green curves show hypothetical Earths with density constant (dashed) and decreasing linearly from center to surface (stippled)|300x300px]]

The '''preliminary reference Earth model''' ('''PREM''') is a one-dimensional [[Scientific modelling|model]] representingplots the average of [[Earth]]'s properties as a function of planetaryby radiusdepth.<ref>{{cite journal|last1=Dziewonski|first1=Adam M.|date=June 1981 |title=Preliminary reference Earth model |journal=Physics of the Earth and Planetary Interiors |volume=25 |issue=4 |pages=297–356 |url=https://www.cfa.harvard.edu/~lzeng/papers/PREM.pdf|doi=10.1016/0031-9201(81)90046-7 |last2=Anderson |first2=Don L. |bibcode=1981PEPI...25..297D}}</ref> It includes a table of Earth properties, including [[elasticity (physics)|elastic]] properties, [[Anelastic attenuation factor|attenuation]], [[density]], [[pressure]], and [[Gravity of Earth|gravity]], as a function of planetary radius.

PREM has been widely used as the basis for [[seismic tomography]] and related global [[geophysics|geophysical]] models.<ref>{{cite book|last=Dziewonski |first=A. M. |last2=Romanowicz |first2=B.A. |title=1.01 - Overview|journal= Treatise on Geophysics |editor-first=Gerald |editor-last=Schubert |date=2007 |pages=1–29 |isbn=9780444527486 |doi=10.1016/B978-044452748-6.00001-8}}</ref> It incorporates anelastic dispersion and [[seismic anisotropy|anisotropy]] and therefore it is frequency-dependent and transversely [[Isotropy|isotropic]] for the [[upper mantle (Earth)|upper mantle]].