CVM-H

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 (11.1.0_RC) is an important milestone for SCEC, as it represents the integration of various model components, including fully 3D waveform tomographic results. The CVM-H 11.1.0 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 11.1.0 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 an initial release candidate, labeled 11.1.0_RC.

Dependencies

None.

Source code

Latest Version:

• SCEC CVM-H: cvmh_11.1.0_RC.tgz
• md5sum: cvmh_11.1.0_RC.tgz.md5

Velocity models used in evaluating 11.1.0_RC:

• CVM-S4 (CVM-4 with Geoff Ely bug fixes): cvm4_gely_20101209.tar
• CVM-H63 (CVM-H v63 model + vx_lite and C API): cvmh_v63.tgz

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:

• Browse and submit new tickets at CVM-H Trac

• Email software@scec.org with specific questions

License

The current CVM-H distribution includes the CVM-H v6.3 software previously released by John Shaw's research group. The CVM-H v6.3 software is released under an open-source Harvard software license CVM-H Harvard. All remaining software in the current CVM-H distribution 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

• Harvard Modeling Group Page
• Goodness of Fit
• CVM-S
• CVM Toolkit

See Also

• SCEC Software Downloads
• SCEC Wiki Main
• SCEC Home Page

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