Gridded Data

Gridded data files are presented in two formats, text and binary. Both formats for a given file contain the same information. The text file is white-space delimited and can easily be imported into a spreadsheet application (eg. Microsoft Excel™) for further analysis. The binary format is more useful for programatic access from custom software.

File Contents Spectral Acceleration Return Period Downloads
Hazard Curves Peak Ground Acceleration Not Applicable [ TEXT | BINARY ]
Hazard Curves 0.1 Second (10Hz) Not Applicable [ TEXT | BINARY ]
Hazard Curves 0.2 Second (5Hz) Not Applicable [ TEXT | BINARY ]
Hazard Curves 0.3 Second (3.33Hz) Not Applicable [ TEXT | BINARY ]
Hazard Curves 0.5 Second (2Hz) Not Applicable [ TEXT | BINARY ]
Hazard Curves 1.0 Second (1Hz) Not Applicable [ TEXT | BINARY ]
Hazard Curves 2.0 Second (0.5Hz) Not Applicable [ TEXT | BINARY ]

File Formats

Text File Formats

These files are simple white-space delimited files. The format should be farily easy to decipher without much guidance.

Binary File Formats

These files were created from the text files and have the same format. In order to help with programatic reading of these files there is additional header information at the top of these files. Header information contains:

  • FileType (int)
    0 → Hazard Curve File
    1 → Ground Motion File
  • Minimum Latitude (double)
  • Maximum Latitude (double)
  • Minimum Longitude (double)
  • Maximum Longitude (double)
  • Grid Spacing (double) - The decimal degree increment between adjacent latitudes/longitudes
  • Num Curve Points (int) - The number of points per hazard curve. This value is only present in hazard curve files.

For convenience we provide sample binary file readers for potential developers to examine the source and get a better idea of how to read the file format. Download our reader (requires Java™). To use this application, open a command line terminal and type: java -jar USParser.jar <datafile>.

Catalog Data

In addition to the output data files below we also make available to you the catalog data used when performing our analysis.

Cautionary Note

We understand why you might be interested in obtaining these catalog files, but are concerned that they might be misused. We have merged catalogs from several different sources, and used fairly subjective criteria to rank our preferences. We have used simple, automated schemes to compute magnitudes and remove aftershocks. To the extent that the original catalogs are not valid research tools, neither are ours! Please read the accompanying documentation, and ask whether these catalogs suit your purpose.

Column Definitions

Each file contains white-space delimited ASCII data organized into the following columns:

  1. Magnitude (mb for CEUS, Mw for WUS)
  2. Longitude (decimal degrees, east)
  3. Latitude (decimal degrees, north)
  4. Depth (km)
  5. Year
  6. Month
  7. Day
  8. Hour
  9. Minute
  10. Second
  11. Name of source catalog