Engineers should typically use the tools below for seismic design; the parameter values they provide are not identical to those from hazard tools available elsewhere on the USGS website.
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 Web Services provide seismic design parameter values from numerous design code editions.
These web services replace the former U.S. Seismic Design Maps Web Applications, which were streamlined due to insufficient resources and the recent development of similar web tools by third parties. Whereas the former applications each interacted with users through a graphical user interface (GUI), the replacement web services receive the inputs (e.g. latitude and longitude) in the form of a web address and return the outputs (e.g. SDS and SD1) in text form, without supplementary graphics. Though designed primarily to be read by the aforementioned third-party web GUIs (e.g. from ASCE, SEAOC/OSHPD, and ATC), the text outputs are also human-readable. Step-by-step instructions for using one of these web services, namely that for the recently published ASCE/SEI 7-16 standard, are posted here. Most users will find the third-party web GUIs to be more usable than these underlying USGS web services.
This web tool calculates risk-targeted ground motion values from probabilistic seismic hazard curves in accordance with the site-specific ground motion procedures defined in “Method 2” (Section 184.108.40.206) of the ASCE/SEI 7-10 and 7-16 standards. The vast majority of engineering projects in the U.S. will require use of the U.S. Seismic Design Maps Web Services (see above) rather than this Risk-Targeted Ground Motion Calculator.