Insights From the Source Physics Experiments on Seismic Waves Generated by Explosions
Date: 4/24/2019
Time: 10:45 AM
Room: Cascade I
The Source Physics Experiments (SPE) are a large multi-institutional (LANL, LLNL, SNL, MSTS and UNR) endeavor to improve our understanding of how explosions generate seismic waves, particularly shear waves to improve nuclear monitoring capabilities. The SPE includes a series of chemical explosions in southern Nevada in two different boreholes in contrasting geologies. The explosions vary in size and depth and for each borehole they are recorded on a common network, allowing ratios between events to be formed, canceling path and site effects and illuminating near source effects due to size, depth, and media. In Phase I, six chemical explosions ranging from about 0.1 to 5 tons in TNT equivalent yield were detonated between 2011 and 2016 in the same granite borehole. In Phase II, four chemical explosions will be detonated in the same borehole, but in a dry alluvium geology (DAG). The first explosion, DAG-1, was conducted on July 20, 2018 at depth of 385 m and had a TNT equivalent yield of approximately 1 ton. The second explosion, DAG-2 was successfully executed on December 19, 2018 at a depth of 300 m with a TNT equivalent yield of about 51 tons.
Comparing large-to-small spectral ratios shows the explosion media has a very large effect on the seismic waves generated. We show the spectral ratios are not well matched by existing explosion models, and that the dry alluvium geology produces smaller amplitudes and appears deficient in high frequency energy relative to explosions in granite. Here we report on the initial results of comparing and contrasting explosions characteristics in wet granite and dry alluvium, examining factors such as absolute depth and scale depth effects, shear wave generation, P/S and low/high frequency amplitude discrimination performance, and correlation behavior. These results are being used to develop a new explosion spectral model, to better predict the effects of small, over-buried explosions in both low and high gas porosity media.
Presenting Author: William R. Walter
Authors
William R Walter walter5@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States Presenting Author
Corresponding Author
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Sean R Ford ford17@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Arben Pitarka pitarka1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Moira Pyle pyle4@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Michael E Pasyanos pasyanos1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Gene A Ichinose ichinose1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Andrea Chiang chang4@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Robert J Mellors mellors1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Souheil M Ezzedine ezzedine1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Oleg Y Vorobiev vorobiev1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Douglas Dodge dodge1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Eric Matzel matzel1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Jeff Wagoner wagoner1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Terri Hauk hauk1@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Danielle Sullivan sullivan42@llnl.gov Lawrence Livermore National Laboratory, Livermore, California, United States |
Insights From the Source Physics Experiments on Seismic Waves Generated by Explosions
Category
Explosion Seismology Applications