### 2.66 Petrovski and Marcellini (1988)

• Ground-motion model is:

where a is in cms2, b1= 6.4830, b2 = 0.5438, b3 = -1.3330, c = 20km and σ = 0.6718 (for horizontal PGA) and b1 = 5.6440, b2 = 0.5889, b3 = -1.3290, c = 20km and σ = 0.6690 (for vertical PGA) (also give coefficients for other choices of c).

• Data from ‘moderate’ soil conditions.
• Data mainly from SMA-1s but 17 from RFT-250s.
• Data from northern Greece (5 records, 4 stations, 3 earthquakes), northern Italy (45 records, 18 stations, 20 earthquakes) and former Yugoslavia (70 records, 42 stations, 23 earthquakes).
• Data from free-field or in basements of structures.
• Select records from earthquakes with 3 M 7. Most earthquakes with M 5.5. 4 earthquakes (4 records) with M 3.5, 20 (27 records) with 3.5 < M 4.5, 13 (25 records) with 4.5 < M 5.5, 8 (50 records) with 5.5 < M 6.5 and 1 (14 records) with M > 6.5.
• Select records from earthquakes with h 40km. Most earthquakes with h 10km. 6 earthquakes with h 5km, 30 with 5 < h 10km, 5 with 10 < h 20km, 4 with 20 < h 30km and 1 with h > 30.
• Select records that satisfied predetermined processing criteria so that their amplitude would be such as to give negligible errors after processing.
• Select records to avoid concentration of records w.r.t. certain sites, magnitudes, hypocentral distances or earthquakes. Most well-recorded earthquakes is 15/4/1979 Montenegro earthquake with 14 records.
• Try values of c between 0 and 40km. Find standard deviation does not vary much for different choices.
• Test assumption of the log-normal probability distribution of data using graph in a coordinate system for log-normal distribution of probability, by χ2 test and by the Kolmogorov-Smirnov test (not shown). Find assumption is acceptable.