- Ground-motion model is: where a is in g, b1 = -1.58, b2 = 0.260, b3 = -0.00346, b4 = -0.625, h0 = 4 and σ = 0.26.
- Do not consider effect of site geology but expect it to be statistically insignificant for PGA.
- Focal depths, h < 25km. Mean focal depth is 10 ± 4km.
- Mean magnitude of earthquakes considered is 6.0 ± 0.7.
- Most records from d < 100km.
- Only use records with PGA > 0.01g.
- Records mainly from SMA-1s located at ground floor or in basements of buildings and structures and
free-field sites regardless of topography.
- Records from thrust earthquakes (46% of total), normal earthquakes (26%) and strike-slip earthquakes
- Baseline correct and low-pass filter records. Select cut-offs from visual examination of Fourier amplitude
spectrum of uncorrected time-histories and choose cut-off below which the Fourier amplitude spectrum
showed an unrealistic energy increase due to digitization noise and instrument distortions.
- Find (from reprocessing about 300 records) that with very few exceptions differences in PGAs arising from
different methods of processing are not significant, remaining below 3%.
- Also derive equation which includes focal depth explicitly.