So, I just discovered PREM (the Preliminary reference Earth model) which models the density distribution of matter inside the Earth to any depth.

The PREM is very convenient but since it only depends on the depth I see that is an isotropic model, meaning that it deoesn't matter from which surface coordinates we are digging, it only accounts for radial variations in density from the core. I know that Earth's interior is not distributed in perfect spherical symmetry since there are things like Large low-shear velocity provinces and giant slabs of solid crust floating in the mantle revealed by seismic tomography, and gravitational anomalies.

I was wondering if there is a much more accurate model for the density distribution of Earth that accounts for the aforementioned asymmetries, and where can I download that data?


1 Answer 1


Here's an extensive list of Earth models, many of which are anisotropic. You'll probably want to focus on tomographic models rather than reference models.


  • $\begingroup$ That's a nice resource but does any of these models include mass density distributions? I only see seismic velocity measurements and I want the mass distribution. $\endgroup$
    – Swike
    May 8, 2021 at 11:00
  • $\begingroup$ Unfortunately, many seismic models don't explicitly provide density. PREM is very convenient in that it gives you a bunch of quantities. Of course, density can easily be calculated from seismic velocities if you have estimates for shear and/or bulk moduli. $\endgroup$
    – g.z.
    May 8, 2021 at 21:12
  • $\begingroup$ How should I proced then? Should I wait a few weeks for someone to show a density model or is it probably not found anywhere? Should I calculate it? How? $\endgroup$
    – Swike
    May 12, 2021 at 15:04
  • $\begingroup$ Waiting probably won't be helpful. I don't know what you're trying to do, so it's kind of hard to give advice on how you should proceed. Why isn't the PREM density profile suitable for what you're trying to do? $\endgroup$
    – g.z.
    May 12, 2021 at 21:10
  • 1
    $\begingroup$ One thing you could do is get an approximation for the shear modulus as a function of depth or pressure, and then use the S-wave velocity from one of the models to calculate density. I can't remember if PREM gives shear modulus as a function of depth, but it's worth checking. Some of the other models in the link I gave might provide it as well. Also, if you're at all familiar with Python, I recommend taking a look at burnman.org. You can build a model of Earth and calculate seismic profiles. You can play around with the mineralogy and see how that changes different properties. $\endgroup$
    – g.z.
    May 15, 2021 at 22:29

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