- Ground-motion model is: where y is in g, α = -1.101, β = 0.2615, b = -0.00255, h = 7.2 and σ = 0.25.
- Uses data and method of Joyner and Boore (1981) but re-evaluates Mw for all earthquakes. Finds some
large changes, e.g. Santa Barbara changes from Mw = 5.1 to Mw = 5.85. Uses ML for 2 earthquakes
(ML = 5.2, 6.2).
- Find effect of uncertainty in Mw causes less than 10% change in σ.
- Also calculates equation using Ms instead of Mw.
- Finds assumption Ms = Mw introduces bias, particularly for small magnitude shocks, on unsafe side, and
this can be significant in cases where there is a preponderance of small earthquakes in set.