Surface Wave Path Corrections, Deterministic Discrimination and Body Wave Attenuation PDF Download

Author: S-cubed (Firm)
Publisher:
ISBN:
Category : Raleigh waves
Languages : en
Pages : 358

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Book Description
Rayleigh waves from the Eastern Kazakh test site recorded at Seismic research Observatory receivers have been analysed for phase-velocity dispersion, group velocity dispersion and spectral amplitude. Linear inversion theory has been used to interpret these data as arising from waves propagating in plane-layered earth models. This yields the mean shear velocity and attenuation over each path as well as the moment of the source. Using the path models, synthetic seismograms have been calculated for use in more refined estimated of source type and source strength. Multivariate linear discrimination has been used to distinguish synthetic body wave spectra of explosions from synthetic body wave spectra of earthquakes. The same algorithm with no modification is highly successful at distinguishing the body wave spectra for real events. High frequency attenuation of the spectra fro real data causes the deterministic discriminant to be biased. It is shown how the bias is used to infer t* (seismic attenuation). The attenuation parameter, t*, has been calculated for Kazakh-SRO and NTS-SRO paths for several score underground explosions. For NTS sources, t* is about 0.8. For Kazakh sources t* ranges between 0.2 and 0.8.