3D Geologic Framework for use with the U.S. Geological Survey National Crustal Model for Seismic Hazard Studies (ver. 2.0, September 2025)

A three-dimensional (3D) geologic framework of the conterminous United States is presented here as part of the U.S. Geological Survey National Crustal Model for Seismic Hazard Studies. The framework is based on 1:250,000 to 1:1,000,000-scale state and continent-wide geologic maps and depths to multiple subsurface unit boundaries. The geology at or near the Earth’s surface is based on published maps with modifications to remove discontinuities across state and country borders. Extrapolation of rock type and age in the subsurface is achieved by iterative stripping of units of a given age, nearest neighbor interpolation of the remaining units, and constraints on basement geology. The subsurface depth of the interfaces between units is determined by a range of models with varying quantity and quality of constraints. Bedrock depth (assumed to be base of Miocene in many cases) is derived primarily from a proxy model with added geophysical constraint in some areas. The depths to the base of Cenozoic and Phanerozoic sedimentary and extrusive volcanic rocks are constrained by geophysical methods in many areas. Elsewhere, a simple method is used to estimate their subsurface depth based on the distance to the edge of the geologic units constrained by well data. The remaining continental units are evenly distributed above, below, and between depending on age. The oceanic crust is treated as a simpler four-layer model with the added complexity of subduction beneath the North American plate along the Cascadia subduction zone. Refinements to this technique can be accomplished in future versions of the model with more specific information including the location of faults to produce discontinuities in geologic structure and additional information obtained from boreholes and geophysical studies. Further improvements to the geologic framework can be made by incorporating information from more local studies, for example, hydrogeologic studies. The 3D Geologic Framework for use with the U.S. Geological Survey National Crustal Model is provided in this data release as multiple linked netcdf files that describe the spatial grid of the model, a series of stacked elevation surfaces, and attributes of rock type and age within the volume of the Geologic Framework. The netcdf files in this data release contain geologic profiles at locations on a 1-km grid across the conterminous United States. Data structure and use of the netcdf files are described in the README file that is part of this release. This data release updates the geologic framework of the National Crustal Model that was initially released in 2019 and updated in 2020. A version history of updates to the framework model is provided in a text file.

                                            [
  "010:12"
]
                                        

                                            {
  "fn": "Boyd, Oliver S.",
  "@type": "vcard:Contact",
  "hasEmail": "mailto:olboyd@usgs.gov"
}
                                        

                                            [
  {
    "@type": "dcat:Distribution",
    "title": "Digital Data",
    "format": "XML",
    "accessURL": "https://doi.org/10.5066/P9SBQENM",
    "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.5cfeb4cce4b0156ea5645056.xml"
  }
]
                                        

                                            [
  "Earthquake Hazards Program",
  "GHSC",
  "Geologic Hazards Science Center",
  "NCM",
  "USGS",
  "USGS National Crustal Model",
  "USGS:5cfeb4cce4b0156ea5645056"
]
                                        

                                            {
  "name": "U.S. Geological Survey",
  "@type": "org:Organization"
}
                                        

                                            [
  "Geospatial"
]