- Ground-motion model is:
where Y is in cm∕s2, a = 0.883, b = 0.458, c = 1.278, h = 11.515, e = 0.038, f = 0.116, τ = 0.109
(intra-event) and σ = 0.270 (inter-event).
- Use three site classes:
- Rock, V s,30 > 800m∕s. S = 0. 75 records.
- Stiff soil, 360 ≤ V s ≤ 665m∕s. S = 1. 197 records.
- Soft soil, 200 ≤ V s ≤ 360m∕s. S = 2. 63 records.
From initial analysis find that ground-motions on D sites are double those on C sites.
- Use three style-of-faulting categories:
- F = 1
- F = 1
- F = 0
From initial analysis find that thrust and strike-slip ground motions are similar but greater than normal
- Focal depths between 0 and 30km with mean of 10.66km.
- Most records from earthquakes near the Ionian islands.
- Use records from free-field stations and from basements of buildings with < 2 storeys. Note that some bias
may be introduced by records from buildings but due to lack of data from free-field stations these records
must be included.
- Use corrected records from ISESD (bandpass filtered 0.25 and 25Hz).
- Use epicentral distance because most earthquakes are offshore and those that are onshore do not display
evidence of surface faulting and therefore cannot use a fault-based distance measure.
- Data from large events recorded at intermediate and long distances and small events at small distances.
Correlation coefficient between magnitude and distance is 0.64.
- Recommend that equation not used outside range of data used.
- Analyse residuals normalized to have zero mean and unity variance (only display results for PGA and SA
at 1s due to similar results for all periods). Find that residuals do not show trends and are uncorrelated
(at more than 99% confidence level) w.r.t. independent variables. Show normality of residuals through
histograms for PGA and SA at 1s.
- Also derive equations for various other strong-motion parameters.