CVM-H 6.2 release

Forwarded CVM release announcement from John Shaw, Harvard:

Dear SCEC colleagues,

The USR Focus Area and the Community Modeling Environment (CME) are pleased to announce the release of the latest version of the Community Velocity Model (CVM-H 6.2). This model describes crust and upper mantle structure in southern California for use in fault systems analysis, strong ground motion prediction, and earthquake hazards assessment.

This latest release of the CVM-H (6.2) is an important milestone for SCEC, as it represents the integration of various model components, including fully 3D waveform tomographic results. The CVM-H 6.2 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 (after 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 6.2 also incorporates a new Moho surface (after Yan and Clayton, 2007) and a series of other upgrades to the geotechnical layer (GTL), the Vp-density scaling relationship, and the code that delivers the model.

The new model is available at:

http://structure.harvard.edu/cvm-h

An updated User Manual, accessible through the website, provides additional information about the model, and detailed instructions on how to access it. Specifically, the manual includes sample data extractions from the model, and specific instruction on how to extract values from the model without topography using code developed by the SCEC CME group.

Please visit the website and contact Andreas Plesch (andreas_plesch@harvard.edu) and John Shaw (shaw@eps.harvard.edu) if you need assistance in accessing or using this new model.

Best regards,

John H. Shaw (Harvard) & Kim Olsen (SDSU), USR Focus Area
Philip Maechling, Community Modeling Environment
Southern California Earthquake Center (SCEC)