where y is in gal, b1= 1080, b2= 0.5, b3= 1.32 and σ = 0.71. 25 adopted from Esteva (1970).
214 (32%) records from San Fernando (9/2/1971) earthquake and 53% of records with PGA less than
Considers portions of data and finds magnitude dependence increases with increasing distance from source
and more small accelerations increase magnitude dependence. Thus magnitude and distance cannot be
considered independent variables.