CVM-H

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SCEC Community Velocity Model - Harvard (CVM-H)

Overview

The CVM-H is a velocity model of crust and upper mantle structure in southern California developed by the SCEC community for use in fault systems analysis, strong ground motion prediction, and earthquake hazards assessment. The model describes seismic P- and S-wave velocities and densities, and is comprised of basin structures embedded in tomographic and teleseismic crust and upper mantle models.

This latest release of the CVM-H (11.2.0) is an important milestone for SCEC, as it represents the integration of various model components, including fully 3D waveform tomographic results. The CVM-H 11.2.0 consists of basin structures defined using high-quality industry seismic reflection profiles and tens of thousands of direct velocity measurements from boreholes (Plesch et al., 2009; Süss and Shaw, 2003). The basin structures are also compatible with the locations and displacements of major faults represented in the SCEC Community Fault Model (CFM) (Plesch et al., 2007). These basin structures were used to develop travel time tomographic models of the crust (after Hauksson, 2000) extending to a depth of 35 km, and upper mantle teleseismic and surface wave models extending to a depth of 300 km (Prindle and Tanimoto, 2006). These various model components were integrated and used to perform a series of 3D adjoint tomographic inversions that highlight areas of the model that were responsible for mismatches between observed and synthetic waveforms (Tape et al, 2009). Sixteen tomographic iterations, requiring 6800 wavefield simulations, yielded perturbations to the starting model that have been incorporated in the latest model release. CVM-H 11.2.0 also incorporates a new Moho surface (Yan and Clayton, 2007) and an upgraded geotechnical layer (GTL) based on a Vs30 map (Ely 2010), the Vp-density scaling relationship, and the code that delivers the model.

Current Release

SCEC CVM-H is currently at release 11.2.0.

Dependencies

None.

Source code

To install and use the CVM-H, you need to download and build the CVM-H software distribution. There are detailed installation instructions on the [CVM-H User Guide]]. The main steps involved in installing CVM-H include: 

  1. The software can be installed in an account on a Linux computer with at least 100G of disk storage and C compilers.
  2. From this Linux computer, start a web browser and point to this download page. Alternatively, you can download the files to a different machine and use FTP or SFTP to copy them over.
  3. Download the following two files (source, source md5sum) into a directory and run the md5sum program to confirm you have an undamaged version of the distribution files.
  4. Uncompress the distribution (tgz) files into a local directory on your computer.
  6. Build the executables by running the top level makefile.
  7. Confirm the code is built correctly by running UnitTests.
  8. Confirm the code runs correctly on your system by running AcceptanceTests.
  9. Use the CVM-H for research purposes.

Latest Version:


Release Candidate 11.1.0_RC:


Velocity models used in evaluating 11.1.0_RC/11.2.0:


Documentation

User Guide (includes installation instructions): CVM-H User Guide


Development version

If you're interested in working with the latest development version of the platform, you can check it out from: 

svn co https://source.usc.edu/svn/cvmh/trunk

Details about working with the development version are provided in the User Guide.


Help

For assistance with the SCEC CVM-H, you may:

  • Email software@scec.org with specific questions


License

The CVM-H software is released under the Apache 2.0 license which is described here CVM-H License.


Release History

11.2.0 - February 2011 - Initial release.


Related Entries


See Also


References

  1. Suess, M. P., and J. H. Shaw, 2003: P-wave seismic velocity structure derived from sonic logs and industry reflection data in the Los Angeles basin, California, Journal of Geophysical Research, 108/B3.
  2. Plesch, A., C. Tape, J. H. Shaw, and members of the USR working group, 2009, CVM-H 6.0: Inversion integration, the San Joaquin Valley and other advances in the community velocity model, in 2009 Southern California Earthquake Center Annual Meeting, Proceedings and Abstracts, vol. 19, pp. 260–261.
  3. Tape, C., Q. Liu, A. Maggi, and J. Tromp, 2009: Adjoint tomography of the southern California crust, Science, v. 325, p. 988-992.
  4. Ely, G., 2010: Vs30 Derived GTL
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