The 3D Reference Earth Model Project: Data, Model and Tools

One-dimensional reference Earth models (e.g. PREM) 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. We discuss a 3D Reference Earth model (REM3D) developed to capture the consensus view of long-wavelength heterogeneity in the mantle. REM3D is constructed through the joint modeling of a reference dataset constructed by reconciling data contributed by several groups across the world.

Our procedures for reconciling datasets include: (1) controlling quality and salvaging missing metadata; (2) identify discrepant measurements and reasons for discrepancies; (3) equalizing geographic coverage by constructing summary rays for travel-time observations; and (4) inverting structure at various wavelengths with a combination of data types to evaluate inter-dataset consistency. We retrieved missing station and earthquake metadata in several legacy compilations and codified scalable formats to facilitate reproducibility, easy storage and fast input/output on high-performance-computing systems. By assessing inter-dataset consistency across similar paths, we quantify travel-time measurement errors for surface and body waves as well as overtones and assess implications of measurement methodology on accuracy.

To facilitate its utility to and adoption by the deep Earth community, we have developed web-based applets, application programming interfaces (APIs) and classes. As a community reference model with quantified uncertainties and tradeoffs and an associated publicly available dataset, REM3D will facilitate Earth imaging studies, earthquake characterization, inferences on temperature and composition in the deep interior, and be of improved utility to emerging scientific endeavors, such as geo-neutrino studies.