Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Preliminary reference Earth model
open-in-new
<p>The preliminary reference Earth model (PREM) plots the average of <a href="/facts/Earth/HLLmDfj0">Earth</a>'s properties by depth. It includes a table of Earth properties, including <a href="/facts/Elasticity_(physics)/wcJoIFg1">elastic</a> properties, <a href="/facts/Anelastic_attenuation_factor/VoCgcbaP">attenuation</a>, <a href="/facts/Density/92p6hh9I">density</a>, <a href="/facts/Pressure/eyc37GRG">pressure</a>, and <a href="/facts/Gravity_of_Earth/IXe9Bh8k">gravity</a>. </p><p>PREM has been widely used as the basis for <a href="/facts/Seismic_tomography/xlRG9zac">seismic tomography</a> and related global <a href="/facts/Geophysics/ywVQ1sAQ">geophysical</a> models. It incorporates <a href="/facts/Anelasticity/Re3X13tL">anelastic</a> dispersion and <a href="/facts/Seismic_anisotropy/qyvuMemV">anisotropy</a> and therefore it is frequency-dependent and transversely <a href="/facts/Isotropy/mc3QEY2x">isotropic</a> for the <a href="/facts/Upper_mantle_(Earth)/5I9jq18K">upper mantle</a>. </p><p>PREM was developed by <a href="/facts/Adam_Dziewonski/fmSzpqk6">Adam M. Dziewonski</a> and <a href="/facts/Don_L._Anderson/MvPvsltz">Don L. Anderson</a> in response to guidelines of a "Standard Earth Model Committee" of the <a href="/facts/International_Association_of_Geodesy/NaI5KDfm">International Association of Geodesy</a> (IAG) and the <a href="/facts/International_Association_of_Seismology_and_Physics_of_the_Earth%25E2%2580%2599s_Interior/7XFwESfQ">International Association of Seismology and Physics of the Earth's Interior</a> (IASPEI) Other Earth reference models include iasp91 and ak135. </p>