- Ground-motion model is:
where ap is in g, for soil sites C1 = -1.86, C2 = 0.23, C3 = -0.0062, C4 = -0.230 and σ = 0.28 and for
rock sites C1 = -1.874, C2 = 0.299, C3 = -0.0029, C4 = -0.648 and σ = 0.33.
- Use two site categories because of limited available information (based on nature of top layer of site regardless of
thickness) for which derive separate equations:
- Use record from free-field or in basements of buildings ≤ 3 storeys high.
- Use Ms because better represents size of shallow earthquakes and is determined from teleseismic readings
with much smaller standard errors than other magnitude scales and also saturates at higher magnitudes
than all other magnitude scales except Mw which is only available for relatively small portion of
earthquakes. For some small earthquakes convert to Ms from other magnitude scales.
- For very short records, ≤ 5s long, correct using parabolic baseline, for records > 10s long correct using
elliptical filter and for records between 5 and 10s long both parabolic correction and filtering applied and
select best one from appearance of adjusted time histories.
- Equations not any more precise than other attenuation relations but are simply included for completeness
and for a comparison of effects of dataset used with other dataset. Data did not allow distinction between
different source mechanisms.