- Ground-motion model is:
Y is in g, a = -4.417, b = 0.770, c = -1.097, s1 = 0, s2 = 0.123, σevent = 0.069 and σrecord = 0.339
(for horizontal PGA assuming intra-event σ), a = -4.367, b = 0.774, c = -1.146, s1 = 0, s2 = 0.119,
σstation = 0.077 and σrecord = 0.337 (for horizontal PGA assuming intra-station σ), a = -4.128, b = 0.722
,c = -1.250, s1 = 0, s2 = 0.096, σevent = 0.085 and σrecord = 0.338 (for vertical PGA assuming intra-event
σ), a = -4.066, b = 0.729, c = -1.322, s1 = 0, s2 = 0.090, σstation = 0.105 and σrecord = 0.335 (for vertical
PGA assuming intra-station σ).
- Use two site classes:
- Rock, where V s > 800m∕s. Use s1.
- Soil, where V s < 800m∕s. This includes all kinds of superficial deposits from weak rock to alluvial
deposits. Use s2.
Can only use two classes due to limited information.
- Use 195 accelerometric records from 51 earthquakes (2.5 ≤ ML ≤ 5.4) from 29 sites. Most records are from
rock or stiff sites. Most data from rhypo < 50km with few from > 100km. Also use data from velocimeters
(Lennartz 1 or 5s sensors and Guralp CMG-40Ts). In total 2895 records with rhypo < 50km from 78 events
and 22 stations available, most from 20 ≤ rhypo ≤ 30km.
- For records from analogue instruments, baseline correct, correct for instrument response and bandpass
filter with average cut-offs at 0.5 and 20Hz (after visual inspection of Fourier amplitude spectra). For
records from digital instruments, baseline correct and bandpass filter with average cut-offs at 0.2 and 30Hz.
Sampling rate is 200Hz. For records from velocimeters, correct for instrument response and bandpass filter
with average cut-offs at 0.5 and 25Hz. Sampling rate is 100Hz.
- Select records from 37 stations with 10 ≤ rhypo ≤ 50km.
- Compare predictions and observations for ML4.4 and find acceptable agreement. Also find agreement
between data from accelerometers and velocimeters.