Research Directed toward the Use of Long and Intermediate Period Seismic Waves for the Identification of Seismic Sources

During the reporting period progress was made in combining long period seismic radiation with independent tectonic information inferred from the global tectonic patterns to constrain the focal mechanisms of events at teleseismic observation distances. In particular the use of the surface wave radiation pattern to solve the focal mechanism of events too small to yield useful body waves has been extended to anomalous intraplate events in Central Asia. The effect of multiple ruptures and other source time-function complications on surface wave focal mechanism determinations is under investigation as part of a tectonic study of the Scotia Sea region. (Modified author abstract) See also AD-774 472.