Maximum-likelihood network magnitude estimates of low-yield underground nuclear explosions. Final report, 3 January-31 March 1994

Technical Report · Thu Mar 31 04:00:00 EST 1994

OSTI ID:6815095

Jih, R S; Baumstark, R R

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.

• Research Organization: Teledyne Geotech, Alexandria, VA (United States). Alexandria Labs.
• OSTI ID: 6815095
• Report Number(s): AD-A-284079/1/XAB; TBE--4617-3; CNN: F09606-91-C-0005
• Country of Publication: United States
• Language: English

Related Subjects

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
450300* -- Military Technology
Weaponry
& National Defense-- Nuclear Explosion Detection
DOCUMENT TYPES
EXPLOSIONS
GEOPHYSICAL SURVEYS
MATHEMATICAL MODELS
NUCLEAR EXPLOSIONS
PROBABILISTIC ESTIMATION
PROGRESS REPORT
SURVEYS