SEA96 Attenuation

In this example, you can calculate the peak horizontal ground acceleration or the psuedovelocity spectrum at a site using the SEA96 attenuation relationship. This relationship was developed specifically for extensional tectonic regimes, which exist in the Basin and Range region of North America and in Western Europe.
Note that the site-to-fault distance is the closest horizontal distance to the vertical projection of the rupture and the relationship is valid over the range of 0 to 80 km only. The valid range of magnitudes is 5.5 < Mw < 7.5. Links to tables of coefficients can be found in Appendix A. Interactive examples for all attenuation relationships can be found in Attenuate©.

Type of analysis:

Select the parameters you wish to use:

Soil Conditions:

Site to fault distance (km):

Moment magnitude (Mw):

Period (s)
Ln median
median + s

PGA (g)

Sa (g)

modify spectrum
to attenuate©

Copyright 1999 Janise Rodgers, Pacific Earthquake Engineering Research Center, University of California, Berkeley.