Infrasound Modeling Using Soviet Explosion Data and Instrument Design Criteria from Experiments and Simulations
MAXWELL TECHNOLOGIES INC SAN DIEGO CA SYSTEMS DIV
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This project has two distinct parts 1 modeling of infrasound signals from atmospheric explosions and evaluation of International Monitoring System network performance using data from historic Russian nuclear tests and other infrasound data sources and 2 analysis of infrasound instrumentation through a program of experimentation and theoretical modeling. The Institute for the Dynamics of the Geospheres IDG in Moscow, Russia, has an archive of infrasound recordings from Soviet atmospheric nuclear tests that were conducted in 1957 and 1961. IDG has digitized a total of 238 infrasound waveforms from 27 atmospheric nuclear tests. Two events were high altitude explosions at Kapoustin Yar, 12 others were at the Shagan River Test Site, and the other 13 were at Novaya Zemlya. 138 of the waveforms have measurable, unclipped signals, known instrument responses, yields, and calibrations. We have been modeling this data in two ways first, by using the data to place constraints on infrasound scaling relations and second, by numerical modeling of the infrasound signals. Scaling relations estimate the pressure as a function of yield and range. Several scaling relations exist in the literature, and the differences between them lead to large differences in estimates of the detection threshold of the International Monitoring System IMS. We find that a scaling relation developed by Los Alamos is most consistent with the data set. We are modeling the waveforms using modal superposition and finite difference calculations, and are also using the Inframap package developed by BBN. IMS network detection capability is predicted using the network simulation programs NetSim and XNICE. NetSim uses joint probabilities together with a scaling relation to calculate the detection threshold.
- Computer Programming and Software
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