Focal Mechanism Determination from S Wave Observations of Different Qualit

Abstract

A least squares method is derived for the focal mechanism determination from S wave observations (polarization angles) of different quality. Some considerations are made on how to determine a weight appropriate to each observation.
As one of numerical examples, a least squares solution is obtained for the Southeast Nevada earthquake of August 16, 1966, that occurred near the Nevada Test Site. This S wave solution represented by a pure strike-slip motion satisfies well the observed initial motions of P waves, and the tension axis trends to S 34°E (±4°) nearly on the horizontal plane.