- Ground-motion model is:
- Soil characteristics known to bedrock for 571 (out of 1013) stations. Classify stations using NEHRP classification
using V
_{s,30}or converted N-values:- A
- V
_{s,30}> 1500m∕s, 0 stations - B
- 760 < V
_{s,30}≤ 1500m∕s, 0 stations - C1
- 460 < V
_{s,30}≤ 760m∕s, 174 stations - C2
- 360 < V
_{s,30}≤ 460m∕s, 193 stations - D1
- 250 < V
_{s,30}≤ 360m∕s, 300 stations - D2
- 180 < V
_{s,30}≤ 250m∕s, 230 stations - E
- V
_{s,30}≤ 180m∕s, 116 stations

Define nonlinear (based on PGA at bedrock) soil amplification model using nonlinear analyses of sampled soil conditions for each class of soils. Use this model to convert observed ground motion to motion at a C1 site.

- Response parameter is acceleration for 5% damping.
- Focal depths, D, between 3 and 122km.
- Distribution with respective to earthquake type (based on mechanism, location and depth) is: crustal (3 ≤ D ≲ 25km), 13; interplate (10 ≲ D ≲ 70km), 23; and intraplate, 16 (30 ≲ D ≤ 122km).
- PGA from 2 to 1114cm∕s2.
- Try including different constant terms to model effect of earthquake type but find lower statistical confidences of results. Therefore remove these coefficients. Believe that modelling of focal-depth dependency may already include effect of earthquake type due to high correlation between depth and type.
- Fit fourth-degree polynomials (in log(T)) through derived coefficients to generate smooth spectra.
- Compare inter- and intra-event residuals to normal distribution using Kolmogorov-Smirnov test and find that the intra-event residuals have a normal distribution and that the inter-event residuals almost have.
- Examine magnitude-dependence of the standard deviations using residuals binned within different
magnitude ranges (M
_{w}< 6.0, 6.0 ≤ M_{w}< 6.5, 6.5 ≤ M_{w}< 7.0 and M_{w}≥ 7.0) and do not find a clear trend for either inter- or intra-event residuals. - Examine distance-dependence of the intra-event standard deviations and find that for some periods the standard deviations show some depth-dependence for short and long distances.
- Examine amplitude-dependence of the intra-event standard deviations and find some positive dependence (σ increases for higher amplitude motions) for T ≤ 0.4s. Note that this may be due to a lack of small amplitude motions due to nontriggering of instruments.