Basic Research in Nuclear Test Monitoring: Seismic Wave Scattering from Irregular Interfaces.

We report on two investigations of seismic wave scattering from irregular interfaces. The first is a laboratory study of the scattering of ultrasonic waves incident on a glass surface etched to produce a highly irregular 3-D interface. We find that 2-D numerical simulations predict the 3-D experimen...

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Bibliographic Details
Main Authors: Schultz, Craig A., Dainty, Anton M., Toksoez, M. N.
Other Authors: MASSACHUSETTS INST OF TECH CAMBRIDGE
Format: Text
Language:English
Published: 1994
Subjects:
Seismology
Nuclear Weapons
*NUCLEAR EXPLOSION TESTING
*SEISMIC WAVES
*PRIMARY WAVES(SEISMIC WAVES)
*SEISMIC ARRAYS
INTERFACES
ACOUSTIC WAVES
SEISMIC DETECTION
BACKSCATTERING
EARTH CRUST
ANGLE OF INCIDENCE
SEISMIC VELOCITY
MOHOROVICIC DISCONTINUITY
SEISMOGRAPHS
NORESS(NORWEGIAN EXPERIMENTAL SMALL SUBARRAY)
ARCESS(ARCTIC EXPERIMENTAL SMALL SUBARRAY)
FINESA(FINNISH EXPERIMENTAL SEISMIC ARRAY)
NYNEX ARRAY
PE61102F
WUAFOSR2309AS
Arctic
Online Access:http://www.dtic.mil/docs/citations/ADA290174
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA290174
Description
Summary:We report on two investigations of seismic wave scattering from irregular interfaces. The first is a laboratory study of the scattering of ultrasonic waves incident on a glass surface etched to produce a highly irregular 3-D interface. We find that 2-D numerical simulations predict the 3-D experimental results well at small incident angles. Both numerical and experimental results strongly support the presence of enhanced backscattering. The second study is an analysis of regional P wave coda observed from events recorded at the Scandinavian NORESS, FINESA, and ARCESS arrays and the New England NYNEX array. The F-K spectra of the P coda are dominated by on-azimuth energy with apparent velocities between Pn (or faster) and Lg. Following this analysis, reflection coefficients calculated with a boundary integral scheme are used to study the role irregular interfaces play in the creation of regional P coda. We find that observed crustal scattering in these regions is strikingly consistent with P-P and P-SV scattering from the 2-D irregular Moho and even more consistent with scattering from a 2-D irregular near surface interface. (MM)

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