Maximum-Likelihood Network Magnitude Estimates of Low-Yield Underground Nuclear Explosions

This final report covers the analysis performed under Task 3 of this contract, using the raw station magnitudes collected under Task One. 35,211 station Mb values from 6 major nuclear test sites have been fed into the GLM (general Linear Model) inversion to determine jointly the event sizes, the sta...

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Bibliographic Details
Main Authors: Jih, Rong-Song, Baumstark, Richard R.
Other Authors: TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
Format: Text
Language:English
Published: 1994
Subjects:
Seismology
Statistics and Probability
Nuclear Explosions and Devices(non-military)
Nuclear Weapons
*UNDERGROUND EXPLOSIONS
*NUCLEAR EXPLOSION TESTING
TEST AND EVALUATION
DATA BASES
MATHEMATICAL MODELS
ALGORITHMS
DATA PROCESSING
REGRESSION ANALYSIS
ERRORS
PLATEAUS
BIAS
INVERSION
STANDARDS
SEISMIC WAVES
SEISMIC DATA
VARIATIONS
UNCERTAINTY
NETWORKS
EXCITATION
MAXIMUM LIKELIHOOD ESTIMATION
PATHS
Novaya Zemlya
Online Access:http://www.dtic.mil/docs/citations/ADA284079
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA284079
Description
Summary:This final report covers the analysis performed under Task 3 of this contract, using the raw station magnitudes collected under Task One. 35,211 station Mb values from 6 major nuclear test sites have been fed into the GLM (general Linear Model) inversion to determine jointly the event sizes, the station corrections, and the specific path correction for each source-station pair. The simultaneously-inferred path and station corrections are related to known geological/geophysical features. Applying these path and station corrections to the raw station magnitudes of any individual explosion yields a systematic reduction in the fluctuational variation of station magnitudes across the whole network with a reduction factor ranging from 1.2 to 3 for all Soviet events in our data set. These station corrections have been used in estimating the event magnitudes of those isolated explosions which were not included in the GLM inversion. With these path-corrected/station-corrected Mb(Pmax), the Mb (Pmax) -mb(Lg) bias between the southwest and northeast subregions of the Soviet's Balapan test site is assessed as 0.08 magnitude unit (m.u.). Magnitude- magnitude regression were conducted with the standard errors in the event magnitudes fully counted for. We observed some inconsistency in the Lg scaling relationships. The systematic bias in the Lg scale can be removed by revising the absolute Lg excitation level for Novaya Zemlya explosions. That is, the Lg scale suitable for Iranian Plateau might be more appropriate for computing Mb(Lg) of Novaya Zemlya explosions. mb, mb(Pn), Mb(Lg), Ms, Mb-Lg Bias, General linear model, Maximum-likelihood, Regression model, Uncertainty.

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