High Frequency Seismic Source Characteristics of Cavity Decoupled Underground Nuclear Explosions PDF Download
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Author: J. R. Murphy
Publisher:
ISBN:
Category :
Languages : en
Pages : 76
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Book Description
The research investigated the high frequency characteristics of the seismic sources corresponding to cavity decoupled nuclear explosions and to assess the implications of these investigations with regard to the detection and discrimination of small decoupled explosions. This study has been carried out using a combination of deterministic simulations and analyses of empirical data recorded from selected cavity decoupled explosions. With regard to the deterministic simulations, a series of nonlinear finite difference calculations have been performed to simulate cavity decoupled explosions in unsaturated tuff and salt emplacement media. These simulations have confirmed the fact that the simple step pressure approximation is not valid at high frequencies and that the initial pressure spike on the cavity wall can induce significant nonlinear response. Preliminary analyses of high frequency seismic data recorded from the STERLING decoupled explosion in salt and the MILL YARD decoupled explosion in unsaturated tuff have provided evidence that the high frequency source components associated with the complex cavity pressure loadings do effectively couple into the seismic regime, in agreement with the predictions of the nonlinear finite difference simulations.
Author: J. R. Murphy
Publisher:
ISBN:
Category :
Languages : en
Pages : 76
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Book Description
The research investigated the high frequency characteristics of the seismic sources corresponding to cavity decoupled nuclear explosions and to assess the implications of these investigations with regard to the detection and discrimination of small decoupled explosions. This study has been carried out using a combination of deterministic simulations and analyses of empirical data recorded from selected cavity decoupled explosions. With regard to the deterministic simulations, a series of nonlinear finite difference calculations have been performed to simulate cavity decoupled explosions in unsaturated tuff and salt emplacement media. These simulations have confirmed the fact that the simple step pressure approximation is not valid at high frequencies and that the initial pressure spike on the cavity wall can induce significant nonlinear response. Preliminary analyses of high frequency seismic data recorded from the STERLING decoupled explosion in salt and the MILL YARD decoupled explosion in unsaturated tuff have provided evidence that the high frequency source components associated with the complex cavity pressure loadings do effectively couple into the seismic regime, in agreement with the predictions of the nonlinear finite difference simulations.
Author: John R. Murphy
Publisher:
ISBN:
Category : Detonation waves
Languages : en
Pages : 86
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 79
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Book Description
This report provides a summary of the results of a joint research program under which scientists from S-CUBED have been working with scientists from the Russian Institute for Dynamics of the Geospheres in an attempt to develop a better understanding of the effects of cavity decoupling on the seismic signals produced by underground nuclear explosions. Investigations conducted under this program have focused on analyses of seismic data recorded from a series of HE cavity decoupling experiments conducted by the Russians in Kirghizia in 1960, and from a sequence of nuclear tests conducted in a water-filled cavity at the Soviet Azgir test site during the period 1975-1979. The Kirghizia series included tests designed to assess the influence of cavity geometry on decoupling effectiveness, and comparisons of near-field seismic data recorded from these tests indicate that the low frequency decoupling factor is independent of cavity shape for elongated cavities with length to width ratios of 6 or more, in agreement with previous theoretical simulation results. Broadband seismic data recorded from the Azgir water-filled cavity tests are analyzed to estimate cavity/tamped source spectral ratios, and the results are compared with theoretical finite difference simulations of these tests.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 66
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Book Description
This report presents a summary of the initial results of an on-going joint research program in which S-CUBED scientists are working with Russian scientists from the Institute for Dynamics of the Geospheres in an attempt to develop a better understanding of the effects of cavity decoupling on the seismic signals produced by underground nuclear explosions. This program includes analyses of seismic data recorded from a series of 10 tamped and 12 decoupled HE tests which were conducted in cavities of different sizes and shapes in Kirghizia in 1960, a theoretical evaluation of the influence of radiation diffusion effects on nuclear cavity decoupling efficiency and an analysis of data recorded from six small (0.01 to 0.50 kt) Russian nuclear tests conducted in a 32 m radius, water-filled cavity in salt at the Azgir test site. (MM).
Author: Ola Dahlman
Publisher: Elsevier
ISBN: 1483165167
Category : Technology & Engineering
Languages : en
Pages : 451
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Book Description
Monitoring Underground Nuclear Explosions focuses on the checking of underground nuclear explosions, including the Comprehensive Test Ban Treaty (CTB), seismological stations, earthquake-source models, and seismicity. The publication first elaborates on test-ban negotiations, nuclear explosions, seismological background, and explosions and earthquakes as seismic sources. Concerns cover comparison between explosion-source and earthquake-source models, theoretical calculation of seismic waves, earth structure, seismicity, nuclear test activities, bomb designs, and disarmament treaties. The manuscript then tackles seismological stations, detection, event definition and location, depth estimation, and identification. Topics include multistation discriminants, statistical aspects, long-period and short-period signals, near distances, location by a network of stations, international data exchange, station detection capabilities, and station networks. The book examines the monitoring of a comprehensive test-ban treaty, nonseismological identification, evasion, peaceful nuclear explosions, and yield estimation. The text is a dependable reference for researchers interested in the monitoring of underground nuclear explosions.
Author:
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ISBN:
Category :
Languages : en
Pages : 11
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Book Description
The dependence of seismic source coupling of underground nuclear explosions on the characteristics of the Q 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 hardrock and water saturated emplacement media (i.e., "good-coupling" media) are roughly consistent with a single nib/yield relation for any fixed tectonic source region, explosions in dry, porous media such as the dry tuffs and alluvium found above the water table at the Nevada Test Site (NTS), are typically observed to have m(b) values at a given yield that are lower than those in hardrock by about 0.50 +/- 0.25 magnitude units. With the exception of the complex cavity decoupling evasion scenario, which is not always feasible, explosions in such low-coupling media define the lower bound on the detection capability required to successfully monitor small, clandestine underground nuclear tests. However, at the present time, no fully reliable seismic source model is available to support quantitative analyses of broadband data recorded from such explosions.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 96
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Book Description
Successful seismic monitoring of any eventual Comprehensive Test Ban Treaty will require the development of a capability to identify signals from small cavity decoupled nuclear explosions from among the numerous signals to be expected from earthquakes, rockbursts and chemical explosion (CE) events of comparable magnitude. The investigations summarized in this report center on a variety of comparative analyses of observed and simulated seismic data corresponding to decoupled nuclear explosions with data recorded from both tamped and near-surface, ripple-fired CE events. More specifically, seismic data recorded from cavity decoupled nuclear tests in both the U.S. and former Soviet Union are used to assess the relative seismic coupling efficiencies of the different types of CE events and to evaluate potential seismic discriminants which might be used to identify the various source types. The results of these comparison studies indicate that tamped CE events with yields on the order of 7 tons and ripple fired CE events with yields in the 70-100 ton range can be expected to produce near-regional ground motion levels comparable to those expected from fully decoupled 1 kt nuclear explosions at Azgir.
Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 724
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Book Description
Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 848
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Book Description
Author: J. R. Murphy
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
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Book Description
The cavity decoupling evasion scenario remains as the greatest challenge to effective seismic monitoring of any eventual CTBT. However, despite the fact that the feasibility of this evasion concept was experimentally established nearly 30 years ago by the U.S. STERLING test, a number of issues of importance with respect to seismic monitoring still remain unresolved. In an attempt to address some of these issues, we have been working with scientists from the Russian Institute For Dynamics of the Geospheres to integrate the limited U.S. and Russian data and modeling experience into a uniform database on cavity decoupling. During the past year, our research has centered on analyses of data recorded from an extensive series of Russian HE cavity decoupling tests conducted in Kirghizia in 1960 and on analyses of seismic data recorded from six Russian nuclear tests conducted in a water-filled cavity at Azgir. The Kirghizia HE cavity decoupling series consisted of 10 tamped and 12 cavity tests in limestone, and included tests of the same yield in both spherical and nonspherical cavities of equal volume. Comparisons of near-field seismic data recorded from these tests indicate that the low frequency decoupling effectiveness is approximately independent of cavity shape for roughly cylindrical cavities with length to width ratios of 6 or more, in agreement with previous theoretical simulation results. Spectral analyses of waveform data recorded at the same distances from 1.0 ton tamped explosions and from a 1.0 ton decoupled test in a spherical cavity with a radius of 2.88 m indicate a maximum low frequency decoupling factor of about 25 for this test.
