- Ground-motion model is:
where Sa is in g, a1 = 0.5781, a2 = -0.0317, b = -0.4352, c1 = -2.6224, c2 = -2.5154, c3 = -2.4654,
c4 = -2.6213 and σ = 0.2768 (for horizontal PGA), a1 = 0.5593, a2 = -0.0258, b = -0.6119,
c1 = -2.6261, c2 = -2.6667, c3 = -2.5633, c4 = -2.7346 and σ = 0.2961 (for vertical PGA).
- Use four site classes based on fundamental frequency, f, from receiver functions:
- f > 15Hz. Corresponds to rock and stiff sediment sites with V s,30 > 700m∕s. 22 records. S1 = 1 and
other Si = 0.
- 5 < f ≤ 15Hz. Corresponds to stiff sediments and/or soft rocks with 500 < V s,30 ≤ 700m∕s. 16
records. S2 = 1 and other Si = 0.
- 2 < f ≤ 5Hz. Corresponds to alluvial sites with 300 < V ≤ 500m∕s. 25 records. S3 = 1 and other
Si = 0.
- f ≤ 2Hz. Corresponds to thick soft alluvium. 26 records. S4 = 1 and other Si = 0.
- Separate records into four mechanisms: reverse (14 records), reverse/strike-slip (1 record), strike-slip (26
records) and unknown (48 records).
- Select records that have PGA > 0.05g on at least one component and are of good quality in frequency
band of 0.3Hz or less.
- Find results using one- or two-step regression techniques are similar. Only report results from one-step
- Mw for earthquakes obtained directly from level of acceleration spectra plateau of records used.
- rhypo for records obtained from S-P time difference.
- Most data from rhypo < 60km.
- Bandpass filter records with cut-offs of between 0.08 and 0.3Hz and between 16 and 40Hz.
- Note that the lack of near-field data is a limitation.