- Ground-motion model is (note that there is a typographical error in Kamiyama et al. (1992); Kamiyama (1995)
because rt has been replaced by rc in equations): where Si = 1 for i station, S0 = 0 otherwise, amax is in cm∕s2, b1 = -1.164, b2 = 0.358, ca = 2.91,
rc = 5.3km and σ = 0.247 (Ai given in publications but not reported here due to lack of space).
- Instrument correct records and filter with pass band between 0.24 and 11Hz.
- Model individual soil conditions at each site as amplification factors, AMPi, as described by Kamiyama
and Yanagisawa (1986).
- Most records are from hypocentral distances between 30 and 200km.
- Focal depths between 0 and 130km.
- Models peak ground accelerations independent of magnitude and distance in a fault zone, rt, where
rt = rc10(b1+b2M)∕1.64.
- Constrain decay with distance in far field to -1.64 using results from other studies to avoid problems due
to correlation between M and log 10r.
- Use trial and error method to find rc so that resulting values of rt are consistent with empirical estimates
of fault length from past studies.
- Also give expression using shortest distance to fault plane (rupture distance), R, by replacing the expression
for r ≤ rc and r > rc by one expression given by replacing r, hypocentral distance, by R+rc in expression
for r > rc. This gives PGA independent of magnitude at distance R = 0km.
- Note that use of rhypo is not necessarily best choice but use it due to simplicity.
- Check residual plots; find no trends so conclude adequate from statistical point of view.