- Ground-motion model is:
where Y is in g, b

_{1}= 1.096, b_{2}= 0.444, b_{3}= 0.0, b_{4}= -1.047, b_{5}= 0.038, h = 5.7, σ_{η}= 0.190 (inter-event) and σ_{ϵ}= 0.464 (intra-event) for geometric mean. - AF
_{s}is the amplification factor due to linear and nonlinear soil behaviour used by Atkinson and Boore (2006), which is a function of V_{s,30}and expected PGA at site with V_{s,30}= 760m∕s, PGA_{ref}. Derive equation for PGA_{ref}of form lnPGA_{ref}= b_{1}+b_{2}(M-7)+b_{4}ln((r_{jb}^{2}+h^{2})^{0.5}), where b_{1}= 0.851, b_{2}= 0.480, b_{4}= -0.884 and h = 6.3km for geometric mean (σ not reported). - Use data from the PEER Next Generation Attenuation (NGA) database.
- Investigate the spatial correlation of ground motions and their variabilities.
- Generate datasets using normally distributed values of M (truncated at ±2 standard deviations that are
reported in the PEER NGA database) for earthquakes and lognormally-distributed values of V
_{s,30}(again using standard deviations from PEER NGA database) for stations. Repeat regression analysis and find coefficients very similar to those obtained ignoring the uncertainty in M and V_{s,30}.