The parameters for calculating the acceleration response spectra include the site latitude and longitude, expressed in decimal degrees. The parameter Vs30 describess the average shear wave velocity between 0m and 30m depth, which describes the site soil conditions. As reference, the NEHRP (National Earthquake Hazard Reduction) site classification has been characterized in the past as soil B, C and D with Vs30 values corresponding to 760m/s, 560m/s and 270m/s respectively.
Input should be restricted to coordinates within the state of Oregon and Vs30 values between 200m/s and 1500m/s. By clicking the submit button, the tool outputs a simple text file that can be locally saved and imported into any spreadsheet to plot the spectra. The file contains two columns, the period (seconds) and the spectral acceleration (g).