- Ground-motion model is:
where A is in g, lna = -5.75, b = 1.72, c = 0, d = 1.69 and R0 = 1 (σ not given).
- Few records from free-field, most are in dams or special structures.,
- Because only 62 records, set R0 = 1 and c = 0.
- Most records from earthquakes with ML between 1.5 and 2.0.
- Maximum PGA in set 3.05m∕s2.
- Nonuniform distribution of focal distances. One quarter of records from same hypocentral distance.
Therefore plot PGA of these records against magnitude (1.2 ≲ ML ≲ 4.3 most less than 2.1) to find b.
Then plot bM - lnA against ln(R∕R0) for all records to find a and d.
- Notes limited data.