The Low Frequency Spectral Minimum in Underground Explosion P Spectra

We confirm that a very low frequency discriminant, i.e., the hole due to pP interference, located at the lower extreme of underground nuclear explosion spectra, is preserved in short-period seismic recordings. This is shown repeatedly, from subarray to subarray, in comparisons of (Amchitka Test) LON...

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Bibliographic Details
Main Author: Smart, Gene
Other Authors: TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
Format: Text
Language:English
Published: 1984
Subjects:
Seismology
*SEISMIC DATA
ALEUTIAN ISLANDS
CONTROL
DEPTH
DISCRIMINATE ANALYSIS
EARTH(PLANET)
EARTHQUAKES
INSTRUMENTATION
INTERFERENCE
LOW FREQUENCY
NUCLEAR EXPLOSION TESTING
NUCLEAR EXPLOSIONS
PRIMARY WAVES(SEISMIC WAVES)
RECORDING SYSTEMS
REMOVAL
RESPONSE
SEISMIC WAVES
SHORT RANGE(TIME)
SPECTRA
SPECTRUM ANALYSIS
UNDERGROUND EXPLOSIONS
VERY LOW FREQUENCY
AMCHITKA(ALASKA)
DEPTH OF BURIAL
PP INTERFERENCE
ZERO FREQUENCY SPECTRAL HOLE
LONGSHOT SHOT
LPN-VT/3709/B/PMP
Amchitka
Alaska
Aleutian Islands
Online Access:http://www.dtic.mil/docs/citations/ADA153795
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA153795
Description
Summary:We confirm that a very low frequency discriminant, i.e., the hole due to pP interference, located at the lower extreme of underground nuclear explosion spectra, is preserved in short-period seismic recordings. This is shown repeatedly, from subarray to subarray, in comparisons of (Amchitka Test) LONGSHOT with a control earthquake, in recordings of those events made at LASA. The discriminant, previously neglected as falling outside seismometer spectral range, is available with present recording systems. To isolate the pP effect for observation the explosion spectra are, in effect, divided by the spectral of the control earthquake, removing interference of earth and instrument responses. It is not clear whether use of a control earthquake is unavoidable. Keywords include: Zero-frequency spectral hole; Depth of burial; and pP interference. Sponsored in part by DARPA.

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