SEA96--A New Predictive Relation for Earthquake Ground Motions in Extensional Tectonic Regimes

We present a new predictive relation for horizontal peak ground acceleration and 5% damped pseudo-velocity response spectrum appropriate for predicting earthquake ground motions in extensional tectonic regimes. This new empirical relation, which we denote “Sea96,” was originally derived by Spudich et al. (1996) as part of a project to estimate seismic hazard at the site of a proposed nuclear waste repository at Yucca Mountain, Nevada. Because of the length and relative inaccessibility of that report, we are briefly presenting the Sea96 relation and its derivation here. We developed our relation based on data from extensional regime earthquakes having moment magnitude M > 5.0 recorded at distances less than 105 km. Extensional regions are regions in which the lithosphere is expanding areally. This areal expansion is the result of applied forces that yield a state of stress for which Sv > SHmax > SHmin , where Sv , SHmax , and SHmin represent principal...