Effect of Burial Depth on Seismic Signals. Volume I
Abstract
This report discusses a calculational program aimed at improving the U.S. capability to verify a Threshold Test Ban Treaty (TTBT) by seismic means. The analysis emphasizes shallow bursts, examining both body-wave and surface- wave effects. Two-dimensional inelastic source calculations, using Applied Theory's AFTON program, were made on a representative set of 150 KT explosions. Simple elastic theory is reviewed, indicating the primary body wave from a buried explosion receives positive or negative reinforcement from the free- surface reflection. The more refined calculations, which include inelastic and gravitational effects, indicate a 'reflection' amplitude smaller than that calculated for the elastic case. More important, the reflected wave is relatively delayed in time, so that transitions between positive and negative reinforcement occur at shallower depths of burial. A surface-wave model is developed, based on Green's function. Many problems were encountered in modifying the AFTON source-data program to provide information that was accurate for long-period displacements, and to extrapolate calculations well beyond the reasonable truncation times for the program. Preliminary conclusions are made concerning the need for inelastic source calculations; depth-of-burial effects on signal generation; the resulting yield estimation; possible improved yield estimation procedures; and topographic effects. Volume I presents summaries of the body-wave and surface-wave calculations to date.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1979
- Accession Number
- ADA069863
Entities
People
- Frank J. Thomas
- J. Trulio
- N. Perl
- W. L. Woodie