Welcome to the 3-dimensional Reference Earth Model Webpage!

REM-3D is a project funded by the National Science Foundation and carried out by Raj Moulik, Ved Lekic, Barbara Romanowicz, and Adam Dziewonski.

If you have questions, please do not hesitate to contact us. You might find the answer you are looking for in our new FAQ section.

The aim of the project is to develop a three-dimensional seismic reference model (REM-3D) for the Earth’s mantle, parameterized in terms of shear wavespeed (Vs), compressional wavespeed (Vp), density (ρ), and the 3 additional parameters representing radial anisotropy. Unlike previous reference models of Earth structure, REM-3D will come with uncertainty estimates. This website will, in due time, host:

  • Reference Models: Two versions of the model will be developed to explicitly fit the comprehensive, community-contributed long period seismic dataset, one parameterized in terms of spherical harmonics, and the other as canonical profiles corresponding to major geographic provinces. For more information, click HERE.
  • Reference Datasets: We will compile, reconcile, and distribute a long period reference seismic dataset, including surface wave dispersion measurements, long period absolute and differential body wave measurements, and free oscillation frequencies / attenuation / and splitting. For more information, click HERE.
  • Tools: We will create and make freely available tools for model distribution and for predicting various seismic observables, including full waveforms, as well as tools designed primarily to enable mineral physicists and geodynamicists a straightforward way of (in)validating models against this reference model or directly against the reference dataset. For more information, click HERE.

Input and Guidance from the Deep Earth Community

In order to maximize the likelihood of success and utility to the broader deep Earth community, the REM-3D project receives input from two advisory working groups, one focused on the reference dataset, and the other on the reference model. Additionally, the project has been modified according to input from a CIDER sponsored workshop held at the University of Maryland, College Park in the Spring of 2013.

Workshop: The summary recommendations of the CIDER REM-3D Workshop can be read here.

Working Groups: As of Summer 2015, the reference dataset working group has been constituted and comprises the following members: Eric Debayle, Arwen Deuss, Göran Ekström, Guy Masters, Jeroen Ritsema, Karin Sigloch.

The reference model working group will be set up by Summer 2016.

If you are interested in contributing to the project with datasets, suggestions, or advice, feel free to e-mail us at:

Goals of Project

We hope that REM-3D will benefit the broader scientific community by facilitating:

  1. Mineralogical and thermo-chemical interpretation of seismic velocities and density;
  2. Identification of anomalous / atypical structures in the Earth’s mantle;
  3. Comparison of global and regional tomographic models;
  4. Seismic waveform interpretation, such as the identification of particular seismic phases;
  5. Inversion for 3D Earth structure requires a starting or background model;
  6. Earthquake source characterization using long period data.

The construction of a community-contributed reference dataset will make possible the identification of anomalous seismic wave travel times, surface wave dispersion, normal mode splitting, and waveform features. Furthermore, the tools for predicting seismic observables from input structures that we will create will enable direct evaluation of potential velocity structures predicted by mineral physics and geodynamics experiments and calculations.

Nontechnical explanation of broader significance and importance:

Elastic properties of the Earth’s interior (e.g. density, rigidity, compressibility, etc.) vary with location due to changes in temperature, pressure, composition, and flow. In the 20th century, Earth scientists have used seismic waves emitted by earthquakes and explosions to develop models of how Earth properties vary with depth. Community reference models that grew out of these efforts have proven indispensable in earthquake location, imaging of interior structure, understanding material properties under extreme conditions, and as a reference in other fields, such as particle physics and astronomy. Over the past three decades, more sophisticated efforts by seismologists across the globe have yielded several generations of models of how properties vary not only with depth, but also laterally. Yet, though these three-dimensional (3D) models exhibit compelling similarities at large scales, differences in the methodology, representation of structure, and dataset upon which they are based, have prevented the creation of 3D community reference models. We propose to overcome these challenges by compiling, reconciling, and distributing a long period reference seismic dataset, fro