Skip to main content
U.S. flag

An official website of the United States government

Equations for estimating horizontal response spectra and peak acceleration from western North American earthquakes: A summary of recent work

January 1, 1997

In this paper we summarize our recently-published work on estimating horizontal response spectra and peak acceleration for shallow earthquakes in western North America. Although none of the sets of coefficients given here for the equations are new, for the convenience of the reader and in keeping with the style of this special issue, we provide tables for estimating random horizontal-component peak acceleration and 5 percent damped pseudo-acceleration response spectra in terms of the natural, rather than common, logarithm of the ground-motion parameter. The equations give ground motion in terms of moment magnitude, distance, and site conditions for strike-slip, reverse-slip, or unspecified faulting mechanisms. Site conditions are represented by the shear velocity averaged over the upper 30 m, and recommended values of average shear velocity are given for typical rock and soil sites and for site categories used in the National Earthquake Hazards Reduction Program's recommended seismic code provisions. In addition, we stipulate more restrictive ranges of magnitude and distance for the use of our equations than in our previous publications. Finally, we provide tables of input parameters that include a few corrections to site classifications and earthquake magnitude (the corrections made a small enough difference in the ground-motion predictions that we chose not to change the coefficients of the prediction equations).

Publication Year 1997
Title Equations for estimating horizontal response spectra and peak acceleration from western North American earthquakes: A summary of recent work
Authors D. M. Boore, W. B. Joyner, T. E. Fumal
Publication Type Article
Publication Subtype Journal Article
Series Title Seismological Research Letters
Index ID 70020212
Record Source USGS Publications Warehouse