SCEC Community Velocity Model (CVM-H)

© Harvard University

Who is working on this?
Andreas Plesch, Carl Tape, Peter Suess, Carlos Rivero, John Shaw

In collaboration with:
SCEC, USGS, CGS

Fig. 1: Perspective view of CVM-H looking from the Salton Sea to the NW, which includes basin structures embedded in underlying tomographic and teleseismic surface wave models that extends to a depth of 300km. Vp is shown. See Fig. 2 for location.

Summary



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.

The CVM-H 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.

Please find more information on querying the model and a download option on the SCEC CVM-H web page:

http://scec.usc.edu/research/CVM-H

Poster describing latest advances: scec2011poster.pdf

© Harvard University

Referencing

Use of this model should reference:
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.
and

Plesch, A., C. Tape, JR. Graves, P. Small, G. Ely and J. H. Shaw, 2011, Updates for the CVM-H including new representations of the offshore Santa Maria and San Bernardino basin and a new Moho surface, in 2011 Southern California Earthquake Center Annual Meeting, Proceedings and Abstracts, vol. 21.

The waveform tomographic model is described in:
Tape, C., Q. Liu, A. Maggi, and J. Tromp, 2009, Adjoint tomography of the southern California crust, Science, v. 325, p. 988-992.

Additional references and descriptions of various model components, along with instructions on how to access the model, are available in the manual.

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Structural Geology and Earth Resources Group