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Title: DIAMOND FORTUNE seismic acceleration measurements

Technical Report ·
DOI:https://doi.org/10.2172/6254470· OSTI ID:6254470

DIAMOND FORTUNE was a nuclear explosion detonated inside an 11 m hemispherical cavity in tuff at the Nevada Test Site. Previous cavity explosions such as STERLING and MILL YARD have shown a substantial decrease in the expected ground motion. These types of cavity tests present a serious problem for a Comprehensive Test Ban (CTB). Not only is detection a problem, but presently there is no seismic method to discriminate between a tamped and cavity explosion. DIAMOND FORTUNE allowed us to examine several aspects of a cavity explosion in the context of a CTB. On this test, there were two groups of accelerometers fielded. One group was located in the free-field at sites above and below the cavity within 30 m of the source. The second group consisted of a line of gauges placed in the invert of P-tunnel extending from 44 m to 224 m from the source. The purpose of this arrangement was to measure ground motion in an effort to detect a non-symmetric radiation pattern due to the hemisphere, examine the high frequency propagation of the free-field signals as a possible discriminate, and calculate the decoupling factor. The radiation pattern experiment was conducted in an effort to determine if the asymmetry of a hemispherical cavity could provide a preferred direction of transmission. The analysis indicated a definite radiation pattern with larger amplitudes transmitted through the spherical surface than the plane surface. The possibility of using high frequency signals as a discriminant of tamped versus cavity explosions is implied by the MILL YARD data. MILL YARD was also a nuclear explosion in an 11 m hemispherical cavity. The free-field ground motion signals from this test (<25 m) contained very large high frequency amplitudes ([approx]1000 Hz) in their spectra. DIAMOND FORTUNE also exhibited high frequency signals with comer frequencies twice that of the scaled tamped DISTANT ZENITH event.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
DOE/DP; USDOE Assistant Secretary for Defense Programs, Washington, DC (United States)
DOE Contract Number:
AC04-94AL85000
OSTI ID:
6254470
Report Number(s):
SAND-96-2544; ON: DE97003801
Country of Publication:
United States
Language:
English