Accession Number : ADA325896

Title :   Physical Mechanisms of Quarry Blast Sources,

Corporate Author : MAXWELL TECHNOLOGIES INC SAN DIEGO CA FEDERAL DIV

Personal Author(s) : Barker, T. G. ; mcLaughlin, K. L. ; Bonner, J.

PDF Url : ADA325896

Report Date : JAN 1997

Pagination or Media Count : 52

Abstract : Models of quarry blasts may serve to develop efficient and robust methods for discriminating quarry blasts from other sources. In this report, we present progress on modeling quarry blasts at the Chemline quarry in central Texas and the Black Thunder mine in the Powder River Basin of Wyoming. We observe strong variations in near field ground motions at the Black Thunder mine. Using estimates of site response derived from signal coda, we find that the variations are partly due to local structure. However, variations between nearly co-located shots indicate changes are also due to source mechanism. The data set provided to us at this time does not include all the data taken for these shots and it is anticipated that source and propagation effects can be resolved with the full data set. We have used three dimensional finite difference calculations to interpret near-regional data from the Chemline quarry. The focus here was to examine azimuthal variations and spall and compare them with the effects of local quarry topography. The spall model is the simplest explanation for the Love to Rg ratios and the Love wave radiation pattern. The Rg radiation pattern suggests that a combination of the spall and topographic models may be needed.

Descriptors :   *NUCLEAR EXPLOSION TESTING, *SEISMIC DISCRIMINATION, *BLAST, DATA BASES, MATHEMATICAL MODELS, UNDERGROUND EXPLOSIONS, GROUND MOTION, FINITE DIFFERENCE THEORY, SEISMIC DATA, SEISMIC WAVES, NUCLEAR EXPLOSION DETECTION, RAYLEIGH WAVES, LOVE WAVES.

Subject Categories : Seismic Detection and Detectors
      Nuclear Weapons

Distribution Statement : APPROVED FOR PUBLIC RELEASE