A Lower Bound on the Standard Error of an Amplitude-based Regional Discriminant

Wave path, magnitude, and signal processing corrections made to observed regional amplitudes fundamentally contain information regarding only the seismic source. These corrected amplitudes can then be used in ratios to discriminate between earthquakes and explosions. Source effects that are due to depth, focal mechanism, local material property and apparent stress variability that cannot easily be determined still remain in the signal. These effects establish a lower bound on the amplitude variability for new events, even after path and magnitude corrections are applied. We develop a general strategy to account for amplitude correction inadequacy by appropriately partitioning error. The proposed mathematics are built from random effects analysis of variance (ANOVA) and have application potential to a variety of amplitude correction theories, for example, see Taylor and Hartse (1998), Taylor et al. (2002), and Walter and Taylor (2002). The error components from random-effects ANOVA are the basis for a general station-averaged regional discriminant formulation. The standard error of the discriminant has a lower bound of amplitude correction error. The developed methods are demonstrated for a suite of Nevada Test Site (NTS) events observed at regional stations. 28th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies