### 2.362 Saffari et al. (2012)

• Ground-motion model is:

where A is in gal, a = 0.38, b = 0.0045, d = 0.005, c1 = 1.30, c2 = 1.35, c3 = 1.53, f = 0.03, g = 0.02, σintra = 0.23, σinter = 0.16 and σtotal = 0.28.

• Use 3 site classes (same as Iranian Code of Practice for the Seismic Resistant Design of Buildings):
I
V s,30 > 750ms. Average V s,30 = 994ms. 135 records. c1 = 1 and c2 = c3 = 0.
II
375 V s,30 750ms. Average V s,30 = 558ms. 160 records. c2 = 1 and c1 = c3 = 0.
III
175 V s,30 375ms. Average V s,30 = 306ms. 56 records. c3 = 1 and c1 = c2 = 0.

There is a fourth class in the Iranian code (V s,30 < 175ms) but no records from this class so not considered in model.

• Consider two faulting mechanisms:
Reverse-thrust
F = 0
Strike-slip
F = 1

Exclude data from normal-faulting events, which occur rarely in Iran.

• Use data from free-field or ground floors from stations of the Iran Strong Motion Network of the Building and Housing Research Centre from 07/03/1975 to 07/12/2008. Data from SSA-2 (digital) and SMA-1 (analogue) instruments.
• Select data using these criteria: Mw 5.0, records from ground surface and both horizontal components available. Apply Mw-dependent truncation of distant records because instrument acceleration trigger is 10gal.
• Consider difference in motions between Central Iran (42 events, Z = 0) and Zagros (36 events, Z = 1) zones, where tectonics are different.
• Focal depths between 5 and 34km. Exclude deeper events because insufficient data.
• Filter records with bandpass cosine filter with cut-offs 0.2 and 20Hz, which were chosen based on characteristics of instruments.
• Exclude data from events with specific geological or other effects.
• 83% of data have PGA< 100gal hence do not consider nonlinear site response.
• Majority of data from Mw 6.5.
• Examine residuals w.r.t. Mw, r, focal depth, zone and faulting mechanism and find no significant trends. Based on these plots believe model reliable for 5.0 Mw 7.3 in Central Iran and 5.0 Mw 6.5 in Zagros, 15 rrup 135km and focal depths 727km.
• Believe higher motions in Zagros zone due to ductile bed, which means ruptures do not reach surface.