The SPiRaL model is a joint model of P- and S-wave speeds and vertical transverse isotropy (VTI) variations from the surface to the core. The model is parameterized using spherical tessellation grids and includes ellipticity, mantle stretching, coarse topography/bathymetry, and multiple crustal units (water, ice, sediments, and crystalline layers) as part of the model.
|Title||Global 3-D Earth Model|
|Type||3D tomography Earth model|
|Sub Type||Vs and Vp velocities with 3-D variations in vertical transverse isotropy (Includes: Vsv, Vsh, Vpv, Vph, eta)|
|EMC Data Revision||r0.0 (revision history)|
|Short Description|| The SPiRaL model is a joint model of P- and S-wave speeds and vertical transverse isotropy (VTI) variations from the surface to the core. The model is parameterized using spherical tessellation grids and includes ellipticity, mantle stretching, coarse topography/bathymetry, and multiple crustal units (water, ice, sediments, and crystalline layers) as part of the model. SPiRaL is a multi-resolution model with node spacing ranging from about 0.25 to 2 degrees and includes undulating surfaces including crustal and transition zone discontinuities. It is based on the joint inversion of S- and P-wave travel times as well as Rayleigh and Love wave phase and group velocities in the 25-200 second period range.
|Usage Notes||For visualization purposes, the model is available here in netCDF format. However, for ray-tracing and travel-time prediction purposes, the Full tessellated version (see below) should be downloaded.|
|Authors:||Nathan Simmons (email@example.com), Steve Myers, Christina Morency, Andrea Chiang, Doug Knapp
Atmospheric, Earth and Energy Division – Lawrence Livermore National Laboratory, Livermore, California
|Previous Model||LLNL-G3D-JPS (Simmons et al., 2015)|
|Model Download||Flattened and interpolated version for visualization purposes only, in netCDF 3 Classic format SPiRaL-1.4.Interpolated.Flattened-viz-only.r0.0.nc, (metadata).
Full tessellated version (ascii files, SPiRaL_1.4_Tessellated.zip)
Interpolated version to 1×1 degree grids (ascii files, SPiRaL_1.4_Interpolated.zip)
|Depth Coverage||Surface to the core mantle boundary|
|Area||Global (-90°/90°, -180°/180°)|
|Data Set Description||The data used to construct the model include millions of P- and S-wave travel times including crustal, regional, and teleseismic phases recorded at thousands of stations (see Simmons et al., 2021). We also incorporated surface wave constraints including Rayleigh and Love fundamental mode dispersion curves (phase and group velocities in the 25-200 second period band) from Ma et al., 2014 and Ma and Masters, 2014.|
To cite the original work behind this Earth model:
- Simmons N. A., S. C. Myers, C. Morency, A. Chiang, and D. R. Knapp (2021). SPiRaL: A multi-resolution global tomography model of seismic wave speeds and radial anisotropy variations in the crust and mantle, Geophys. J. Int., 227(2), 1366-1391, doi:/
To cite IRIS DMC Data Products effort:
- Trabant, C., A. R. Hutko, M. Bahavar, R. Karstens, T. Ahern, and R. Aster (2012), Data Products at the IRIS DMC: Stepping Stones for Research and Other Applications, Seismological Research Letters, 83(5), 846–854, https://doi.org/10.1785/0220120032.
DOI for this EMC webpage: https://doi.org/10.17611/dp/emc.2021.spiral.1
- Ma, Z., and G. Masters (2014). A New Global Rayleigh- and Love-Wave Group Velocity Dataset for Constraining Lithosphere Properties, Bull. Seism. Soc. Amer., 104, 2007-2026, https://doi.org/10.1785/0120130320
- Ma, Z., G. Masters, G. Laske and M.E. Pasyanos (2014). A comprehensive dispersion model of surface wave phase and group velocity, Geophys. J. Int., 199, 113-135, https://doi.org/10.1093/gji/ggu246
- Simmons, N.A., S.C. Myers, G. Johannesson, E. Matzel and S.P. Grand (2015). Evidence for long-lived subduction of an ancient tectonic plate beneath the southern Indian Ocean, Geophys. Res. Lett., 42, 9270-9278, https://doi.org/10.1002/2015GL066237
- Nathan Simmons, Steve Myers, Christina Morency, Andrea Chiang, Doug Knapp
revision r0.0: uploaded September 16, 2021.