San Francisco Bay region 3D seismic velocity model v26.0
This three-dimensional (3D) seismic velocity model includes a detailed domain covering the greater San Francisco Bay urban region and a regional domain at a coarser resolution covering a larger region. Version 26.0 updates only the detailed domain with adjustments to the elastic properties west of the Hayward fault system. There are no changes to the underlying 3D geologic model or the regional domain seismic velocity model. The model was constructed by assigning elastic properties (density, Vp, Vs, Qp, and Qs) to grids of points based on the geologic unit and depth from the ground surface. See accompanying document for details on velocity-depth rule updates.
Model updates include:
- New velocity-depth rules for Quaternary and Tertiary zones west of the Hayward fault, obtained by fitting power law functions to borehole data
- Updated velocity-depth rule for Gabbro zones, obtained by fitting data from 2D seismic reflection profile across the San Leandro Gabbro
- Replaced velocity-depth rule used for Granite with a previous rule defined by Brocher (2005)
- Updated velocity-depth rule for Lower Crust, with increase of Vs by 1 km/s
The model is stored in HDF5 files using the GeoModelGrids (https://geomodelgrids.readthedocs.io) storage scheme. GeoModelGrids provides a high-level interface for accessing the model. The model can also be accessed using the HDF5 application programming interface provided with many programming languages and tools, but the user will be responsible for all coordinate transformations.
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Complete Metadata
| accessLevel | public |
|---|---|
| bureauCode |
[ "010:12" ] |
| contactPoint |
{ "fn": "Evan T Hirakawa", "@type": "vcard:Contact", "hasEmail": "mailto:ehirakawa@usgs.gov" } |
| description | This three-dimensional (3D) seismic velocity model includes a detailed domain covering the greater San Francisco Bay urban region and a regional domain at a coarser resolution covering a larger region. Version 26.0 updates only the detailed domain with adjustments to the elastic properties west of the Hayward fault system. There are no changes to the underlying 3D geologic model or the regional domain seismic velocity model. The model was constructed by assigning elastic properties (density, Vp, Vs, Qp, and Qs) to grids of points based on the geologic unit and depth from the ground surface. See accompanying document for details on velocity-depth rule updates. Model updates include: - New velocity-depth rules for Quaternary and Tertiary zones west of the Hayward fault, obtained by fitting power law functions to borehole data - Updated velocity-depth rule for Gabbro zones, obtained by fitting data from 2D seismic reflection profile across the San Leandro Gabbro - Replaced velocity-depth rule used for Granite with a previous rule defined by Brocher (2005) - Updated velocity-depth rule for Lower Crust, with increase of Vs by 1 km/s The model is stored in HDF5 files using the GeoModelGrids (https://geomodelgrids.readthedocs.io) storage scheme. GeoModelGrids provides a high-level interface for accessing the model. The model can also be accessed using the HDF5 application programming interface provided with many programming languages and tools, but the user will be responsible for all coordinate transformations. |
| distribution |
[ { "@type": "dcat:Distribution", "title": "Digital Data", "format": "XML", "accessURL": "https://doi.org/10.5066/P13AEJFI", "mediaType": "application/http", "description": "Landing page for access to the data" }, { "@type": "dcat:Distribution", "title": "Original Metadata", "format": "XML", "mediaType": "text/xml", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.6a3dbb951ba49b50a1948e89.xml" } ] |
| identifier | http://datainventory.doi.gov/id/dataset/USGS_6a3dbb951ba49b50a1948e89 |
| keyword |
[ "California", "San Francisco Bay", "USGS:6a3dbb951ba49b50a1948e89", "earth structure", "earthquake", "geologic structure", "physical modeling", "seismic velocity model", "seismology", "three dimensional model" ] |
| modified | 2026-08-14T00:00:00Z |
| publisher |
{ "name": "U.S. Geological Survey", "@type": "org:Organization" } |
| spatial | -126.3216, 35.0364, -118.9787, 41.4586 |
| theme |
[ "geospatial" ] |
| title | San Francisco Bay region 3D seismic velocity model v26.0 |
