DOBRY DURATION

Dobry and others (1978) defined a specific measure of the shaking duration of an earthquake acceleration-time history (strong-motion record) based on Arias (1970) intensity. Dobry duration is the time required to build up the central 90 percent of the Arias (1970) intensity. Dobry and others (1978) proposed an empirical relationship between this measure of duration and earthquake magnitude:

log D_(5-95%) = 0.432M - 1.83

where D_(5-95%) is Dobry duration in seconds, and M is unspecified earthquake magnitude (probably local magnitude).