- Ground-motion model is:
_{0}= -1.2780 ± 0.1909, b_{1}= 0.2853 ± 0.0316, b_{2}= -1.730 × 10^{-3}± 2.132 × 10^{-4}and σ = 0.3368 (± indicates the standard deviation of the coefficients). h was fixed arbitrarily to 8km. - Use data from ISESD (Ambraseys et al., 2004). Select using d
_{e}< 1000km, 5 ≤ M ≤ 7 (where M is either M_{w}or M_{s}). - Focal depths < 20km.
- Only use data from strike-slip earthquakes.
- Note that coefficient of variation for b coefficients is in range 11 to 15%.
- Note that b
_{0}and b_{1}are very strongly negatively correlated (correlation coefficient of -0.9938), believed to be because PGA is governed by b_{0}+ b_{1}M as D approaches zero, but they are almost uncorrelated with b_{2}(correlation coefficients of -0.0679 and -0.0076 for b_{0}and b_{1}respectively), believed to be because of zero correlation between M and D in the data used. - Also derive equation using log
_{10}(PGA) = b_{0}+ b_{1}M + b_{2}R + b_{3}log_{10}(R) (do not report coefficients) and find slightly smaller residuals but similar behaviour of the b parameters. - Plot distribution of residuals (binned into intervals of 0.25 units) and the normal probability density function.