- Ground-motion model is:
- Use two site classes:
- LR = 1, LS = 0.
- LS = 1, LR = 0.
- Focal depths between 7 and 72km with most between 10 and 30km.
- Response parameter is acceleration for 5% damping.
- Use data from Iranian Strong-Motion Network run by Building and Housing Research Centre.
- Select data based on these criteria: Mw ≥ 5, record on ground surface (free-field) and two orthogonal
horizontal components available. Apply a Mw-dependent distance filter. After first regression data again
truncated based on the median plus one σ model and a trigger level of 10gal.
- Examine data binned by Mw w.r.t. distance and remove earthquakes with irregular distributions (due to
tectonic or other reasons).
- Baseline correct and bandpass filter (cut-offs of 0.2 and 20Hz) data based on characteristics of instruments
(SSA-2 and SMA-1).
- Use rock data to define all coefficients and then compute cSoil and σSoil using soil data and the coefficients
defined from rock data (details not given).
- Smooth coefficients using fifth-degree polynomial based on logarithm of period.
- Derive coefficients for central Iran and Zagros separately.