where Y is in g, for randomly-oriented horizontal component (or geometrical mean) b1= -0.105, b2=0.229, b3= 0, b4= 0, b5= -0.778, b6= 0.162, b7= 0.251, h = 5.57 and σ = 0.230 (for geometrical mean
σ = 0.208) and for larger horizontal component b1= -0.038, b2= 0.216, b3= 0, b4= 0, b5= -0.777,
b6= 0.158, b7= 0.254, h = 5.48 and σ = 0.205.
Due to an error in Equation (3) of Boore et al. (1994a) and Equation (6) of Boore et al. (1997) σc
reported in Boore et al. (1994a, 1997) are too large by a factor of . Therefore correct values of standard
deviations are: σf= 0.431, σc= 0.160, σr= 0.460, σs= 0.184 and σlnY= 0.495.
Use three site categories:
Vs,30> 750m∕s, some categorised using measured shear-wave velocity, most estimated ⇒ GB=0,GC= 0, 48 records
360 < Vs,30≤ 750m∕s, some categorised using measured shear-wave velocity, most estimated
⇒ GB= 1,GC= 0, 118 records.
180 < Vs,30≤ 360m∕s,some categorised using measured shear-wave velocity, most estimated
⇒ GB= 0,GC= 1, 105 records.
where Vs,30 is average shear-wave velocity to 30m.
Define shallow earthquakes as those for which fault rupture lies mainly above a depth of 20km.
Peak acceleration scaled directly from accelerograms, in order to avoid bias from sparsely sampled older
Do not use data from structures three storeys or higher, from dam abutments or from base of bridge
columns. Do not use data from more than one station with the same site condition within a circle of radius
1km (note that this is a somewhat arbitrary choice).
Exclude records triggered by S wave.
Do not use data beyond cutoff distance which is defined as equal to lesser of distance to the first record
triggered by S wave and closest distance to an operational nontriggered instrument.
Note that little data beyond 80km.
Due to positive values of b4 when b5= -1, set b4 to zero and let b5 vary.