LITHO1.0

An updated crust and lithospheric model of the Earth

Michael Pasyanos (LLNL), Guy Masters (IGPP), Gabi Laske (IGPP), and Zhitu Ma (IGPP)

UPDATE (February 23, 2016): Collection of surface wave dispersion maps is now available as a single zip file. Go to Surface Wave Models and Codes 3) for explanation.
UPDATE (July 15, 2014): We have discovered an issue with the interpolator used in access_litho, which results in non-physical (e.g. negative) values for model parameters at certain points. This occurs when the point of interest goes out of the triangle on a curved sphere, which gives weighting values for adjacent nodes outside of the 0-1 range. Until a fix is implemented, a workaround solution is to slightly move the point off of the point of interest.
UPDATE (January 06, 2015): LITHO1.0 model available in ArcGIS format. Scroll down to download section.
UPDATE (June 04, 2014): LITHO1.0 model available in GeoTess format. Scroll down to download section.
MILESTONE (April 10, 2014): LITHO1.0 paper published
UPDATE (March 31, 2014): LITHO1.0 model posted to IGPP website. Scroll down to download section.
UPDATE (March 27, 2014) LITHO1.0 webpage live
MILESTONE (February 28, 2014): LITHO1.0 manuscript accepted to the Journal of Geophysical Research (JGR) - Solid Earth
MILESTONE (November 16, 2013): Surface wave models and codes to calculate predictions. Go to Surface Wave Models and Codes for explanation.

Description of the model

The LITHO1.0 model is a 1° tessellated model of the crust and uppermost mantle of the earth, extending into the upper mantle to include the lithospheric lid and underlying asthenosphere. The model is parameterized laterally by tessellated nodes and vertically as a series of geophysically identified layers, such as water, ice, sediments, crystalline crust, lithospheric lid, and asthenosphere. LITHO1.0 was created by constructing an appropriate starting model, including CRUST1.0 as starting model for the crust. We then perturbed the model to fit high-resolution surface wave dispersion maps (Love, Rayleigh, group, phase) over a wide frequency band (5-40 mHz).

The model was generated by examination and discussion of the model with respect to key lithospheric parameters, such as average crustal velocity, crustal thickness, upper mantle velocity, and lithospheric thickness. We then compared the constructed model with those from a number of select studies at regional and global scales and find general consistency. Details can be found in Pasyanos et al. (2014).

It appears that LITHO1.0 represents a reasonable starting model of the earth's shallow structure (crust and uppermost mantle) for the purposes in which these models are used, such as travel time tomography or in efforts to create a 3D reference earth model. The model matches surface wave dispersion over a frequency band wider than the band used in the inversion. There are several avenues for improving the model in the future by including attenuation and anisotropy, as well as making use of surface waves at higher frequency.

Each of the nodes has a unique profile where the layers are

  1. water
  2. ice
  3. upper sediments
  4. middle sediments
  5. lower sediments
  6. upper crust
  7. middle crust
  8. lower crust
  9. lithospheric mantle (lid)
  10. asthenospheric mantle
  11. ak135

Crustal parameterization was adopted from CRUST1.0 though the depth to Moho and a uniform perturbation in the crystalline crust was allowed in the inversions. Parameters of layer thickness, VP, VS, rho, and Q (placeholder values) are given explicitly for all layers. The parameters below the asthenosphere blend into the ak135 model (Kennett et al., 1995).

Reference

Pasyanos, M.E., T.G. Masters, G. Laske, and Z. Ma (2014). LITHO1.0: An updated crust and lithospheric model of the Earth, J. Geophys. Res., 119 (3), 2153-2173, DOI: 10.1002/2013JB010626..

Model Updates

We would like to update the model as time and funding allow. If you have any data that you feel would be useful to future versions, please contact one of the authors.

Download section - LITHO1.0 Model

 The model in its native format and C++ source code to read it at any arbitrary location (access_litho) is available here. The C++ source code should compile with any standard compiler. To download the compressed tar file, Click here. Use gunzip and then tar to extract the README, model files, C++ source code, and Makefile. Note that the uncompressed tar file is nearly 500 MByte large!

In the future we hope to make the model available in other formats, including on a regular lat/lon grid. Models will be posted here as they become available. A compressed file of the GeoTess version can be downloaded here from the SIO site

GEOTESS
A group at the Sandia and Los Alamos National Laboratories develops 3D tomographic models of the crust and mantle. As part of this, the group developed a model parameterization and software support library for 3D Earth models. Please find more info at their GEOTESS website at www.sandia.gov/geotess.

ArcGIS
An ArcGIS map package of the LITHO1.0 model was created by Stoney Clark of Statoil (STEC-at-statoil.com). The package can be downloaded here.

Download Section - Surface Wave Data and Codes

1) As part of the modeling for LITHO 1.0, a fast program for computing phase and group velocity for fundamental mode Rayleigh and Love waves was needed. The program mineos (versions of which exist at CIG) was modified to do this and is capable of high precision to high frequencies. Because we are modeling relatively long period surface waves, we needed a spherical Earth code that included self-gravitation. We also needed a code that could handle transverse isotropy. The code has been optimized to provide about 4 decimal places of precision in the group and phase velocities - this exceeds the precision of the data. download minos_gv2 here.

2) Surface wave Data and Programs

Programs ReadmeRayleigh wave codesLove wave codes
Phase Data ReadmePhase Data (zip file; 386 MBytes)(Love data included/no extra file)
Group Data ReadmeGroup Data (zip file; 176 MBytes)(Love data included/no extra file)

3) We also provide dispersion maps sampled at a few frequencies. Click here to download single zip file. There are two folders, one for Rayleigh waves and the other one for Love waves. The filename indicates the frequency in mHz.

The frequency ranges are: The format is longitude, latitude, phase velocity, group velocity (in km/s). Note that not all maps are available for all frequencies. Non-existing maps have -99. as values (e.g. Love group velocity at 7 mHz).

Manuscript on group travel time data (published in BSSA)
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, DOI: 10.1785/0120130320 - link to http://dx.doi.org/10.1785/0120130320

Manuscript on dispersion modeling (published in GJI)
Ma, Z., G. Masters, G. Laske, and M. Pasyanos (2014). A comprehensive dispersion model of surface wave phase and group velocity for the globe, Geophys. J. Int., 199, 113-135, DOI: 10.1093/gji/ggu246 - link to http://dx.doi.org/10.1093/gji/ggu246

External links:

LLNL-G3Dv3
Reference: Simmons, N.A, S.C. Myers, G. Johannesson and E. Matzel (2012), LLNL-G3Dv3: Global P wave tomography model for improved regional and teleseismic travel time prediction, J. Geophys. Res., 117, doi:10.1029/2012JB009525.
Link: Download the LLNL-G3D model from the IRIS website: http://www.iris.edu/dms/products/emc-llnl-g3dv3

AK135
Reference: Kennett, B.L.N., E.R. Engdahl, and R. Buland (1995), Travel times for global earthquake location and phase association, Geophys. J. Int., 122, 108-124. doi:10.1111/j.1365-246X.1995.tb03540.x.

Go to
REM page
REM Crust page
CRUST1.0 page
LITHO1.0: Michael Pasyanos ( pasyanos1@llnl.gov)
Web Page: Gabi Laske ( glaske@ucsd.edu)
Michael's home page
Gabi's home page
Guy's home page