Analysis of the Seismic Source Characteristics of Explosions in Low- Coupling Dry Porous Media (Postprint)

摘要

The dependence of seismic source coupling of underground nuclear explosions on the characteristics of the explosion source medium is an important consideration in any assessment of nuclear test monitoring capability. In particular, while experience has indicated that normal depth explosions in almost all hard rock and water-saturated emplacement media (i.e., good-coupling media) are roughly consistent with a single mb/yield relation for any tectonic source region, explosions in dry, porous media are typically observed to have, at a given yield, mb values lower than those in hard rock by about 0.50-0.25 magnitude units. However, at the present time no fully reliable seismic source model is available to support quantitative analyses of broadband data recorded from such explosions. The technical objectives of this program are to develop a Mueller/Murphy frequency dependent seismic source model for underground nuclear explosions in dry, porous media. P wave seismic source coupling characteristics of explosions in dry, porous media have been studied by analyzing seismic data recorded at the Lawrence Livermore National Laboratory (LLNL) regional network stations from nuclear explosions conducted above and below the water table at the Yucca Flat testing area of Nevada National Security Site NNSS.