Engineers should use these maps and tools for seismic design, not the hazard maps available elsewhere on the USGS website.
U.S. Seismic Design Maps
The USGS collaborates with organizations (such as the Building Seismic Safety Council) that develop model building and bridge design codes to make seismic design parameter values available to engineers. The design code developers first decide how USGS earthquake hazard information should be applied in design practice. Then the USGS calculates gridded values of seismic design parameters based on USGS hazard values in accordance with design code procedures. The U.S. Seismic Design Maps application provides seismic design parameter values from the following design code editions:
- 2013 ASCE/SEI 41
- 2012/09/06 International Building Code
- 2010/05 ASCE/SEI 7 Standard
- 2009/03 NEHRP Recommended Seismic Provisions
- 2009 AASHTO Guide Specifications for LRFD Seismic Bridge Design
The USGS also provides data files and maps of these gridded design values.
U.S. Seismic Design Maps (Beta)
This Beta version of the U.S. Seismic Design Maps application will eventually replace the current version of the application (see above entry) after all of the currently-referenced design code editions are ported over to it. Currently, the Beta version of the application provides parameter values from the 2015 National Earthquake Hazards Reduction Program (NEHRP) Recommended Seismic Provisions for New Buildings and Other Structures. This design code reference document provides seismic design parameter values that are proposed for use in future editions of major U.S. building codes (International Building Code, ASCE 7 Standard).
Risk-Targeted Ground Motion Calculator
This tool is used to calculate risk-targeted ground motion values from probabilistic seismic hazard curves in accordance with the site-specific ground motion procedures defined in “Method 2” of 2010 ASCE 7 Standard Section 21.2.1.2.
The vast majority of engineering projects in the U.S. will require the use of the U.S. Seismic Design Maps application (see above) rather than the Risk-Targeted Ground Motion Calculator.
Help Selecting a Seismic Design Tool