- Ground-motion model is (from definition of local magnitude scale):
_{0}(R) is an empirically determined attenuation function from Richter (1958) used for calculation of M_{L}, p is confidence level and v is component direction (v = 0 for horizontal and 1 for vertical). log A_{0}(R) not given here due to lack of space. - Response parameter is pseudo-velocity for 0, 2, 5, 10 and 20% damping.
- Uses three site categories:
- s = 0
- Alluvium. 63% of data.
- s = 1
- Intermediate. 23% of data. Notes that ideally would not need but had to be introduced because in some cases difficult to make a choice in complex geological environment or because of insufficient data.
- s = 2
- Basement rock. 8% of data.

- Use same data as Trifunac and Anderson (1977). See Section 4.4.
- Use same regression method as Trifunac and Anderson (1977). See Section 4.4.
- Equation constrained to interval M
_{min}≤ M ≤ M_{max}where M_{min}= -b(T)∕2f(T) and M_{max}= [1-b(T)]∕2f(T). For M > M_{max}replace M by M_{max}everywhere and for M < M_{min}replace M by M_{min}in b(T)M and f(T)M^{2}. This gives linear growth for M < M_{min}, parabolic growth for M_{min}≤ M ≤ M_{max}and constant amplitude for M > M_{max}. - 98 records from San Fernando earthquake (9/2/1971) but regression method eliminated 70% of these before computing the coefficients.
- Epicentral distance used for simplicity, consistency with earlier studies and for lack of significantly better choice. Distance measure chosen has small effect whenever epicentral distance greater than several source dimensions.
- Notes that recording and processing noise in signal means that quality of coefficients diminishes for T > 2s. Equations not recommended for periods longer than those for which selected spectral amplitudes plotted.
- Notes that equations should be considered only as preliminary and an empirical approximation to a complicated physical problem.
- Notes that data are limited to narrow magnitude interval, most data comes from alluvium sites and about half comes from one earthquake.
- Only gives coefficients for 11 periods. Graphs of coefficients for other periods.