- Ground-motion model is:
where PSA(f) is in cm∕s2, a(f) = 3.71 × 10-1, b(f) = -2.54 × 10-3, c(A,f) = 0.617, c(B,f) = 0.721,
c(C,f) = 0.845, c(D,f) = 0.891 and σ = 3.13 × 10-1.
- Use four site categories, based on V s,30 (average shear-wave velocity in top 30m) as proposed in Eurocode
- V s,30 > 800m∕s. Use c(A,f). 14 records.
- 400 < V s,30 ≤ 800m∕s. Use c(B,f). 856 records.
- 200 < V s,30 ≤ 400m∕s. Use c(C,f). 1720 records.
- 100 < V s,30 ≤ 200m∕s. Use c(D,f). 421 records.
- Good determination of site conditions between shear-wave velocities have been measured down to 10 to
20m at every site. Extrapolate shear-wave velocity data to 30m to find V s,30. V s,30 at stations is between
about 50m∕s and about 1150m∕s.
- Use data from Kyoshin network from 1996, 1997 and 1998.
- All data from free-field sites.
- No instrument correction needed or applied.
- Use data from earthquakes with MJMA > 3.5 and focal depth < 20km because want to compare results with
Ambraseys et al. (1996) and Boore et al. (1997). Also this criteria excludes data from deep subduction
earthquakes and data that is not significant for seismic hazard studies.
- Homogeneous determination of JMA magnitude and hypocentral distance.
- Roughly uniform distribution of records with magnitude and distance.
- Assume pseudo-spectral acceleration for 5% damping at 0.02s equals PGA.
- Note equation valid for 3.5 ≤ MJMA ≤ 6.3 and 10 ≤ rhypo ≤ 200km.
- Find inclusion of site classification has reduced standard deviation.