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Criteria for the PNE seismic network. [On-site inspection against clandestine operations]

Description: A 1976 treaty between the United States and the Soviet Union permits a local seismic network to be deployed at the site of a peaceful nuclear explosion to monitor the event. Criteria for the design and selection of the data-acquisition equipment for such a network are provided. Constraints imposed by the protocol of the treaty, the environment, and the expected properties of seismic signals (based on experiences at the Nevada Test Site) are discussed. Conclusions are drawn about the desired operating mode. Criteria for a general seismic instrumentation system are described.
Date: March 23, 1978
Creator: Pruvost, N.L. (comp.)
Partner: UNT Libraries Government Documents Department

Preliminary code development for seismic signal analysis related to test ban treaty questions

Description: Forensic seismology, from a present day viewpoint, appears to be divided into several areas. Overwhelmingly important, in view of current Complete Test Ban (CTB) discussions, is the seismological study of waves generated in the earth by underground nuclear explosions. Over the last two decades intensive effort has been devoted to developing improved observational apparatus and to the interpretation of the data produced by this equipment. It is clearly desirable to extract the maximum amount of information from seismic signals. It is, therefore, necessary to quantitatively compare various modes of analysis to establish which mode or combination of modes provides the most useful information. Preliminary code development for application of some modern developments in signal processing to seismic signals is described. Applications of noncircular functions are considered and compared with circular function results. The second portion of the discussion concerns maximum entropy analysis. Lastly, the multivariate aspects of the general problem are considered.
Date: January 1, 1977
Creator: Brolley, J.E.
Partner: UNT Libraries Government Documents Department

Seismic verification of underground explosions

Description: The first nuclear test agreement, the test moratorium, was made in 1958 and lasted until the Soviet Union unilaterally resumed testing in the atmosphere in 1961. It was followed by the Limited Test Ban Treaty of 1963, which prohibited nuclear tests in the atmosphere, in outer space, and underwater. In 1974 the Threshold Test Ban Treaty (TTBT) was signed, limiting underground tests after March 1976 to a maximum yield of 250 kt. The TTBT was followed by a treaty limiting peaceful nuclear explosions and both the United States and the Soviet Union claim to be abiding by the 150-kt yield limit. A comprehensive test ban treaty (CTBT), prohibiting all testing of nuclear weapons, has also been discussed. However, a verifiable CTBT is a contradiction in terms. No monitoring technology can offer absolute assurance that very-low-yield illicit explosions have not occurred. The verification process, evasion opportunities, and cavity decoupling are discussed in this paper.
Date: June 1, 1985
Creator: Glenn, L.A.
Partner: UNT Libraries Government Documents Department

Lightning discrimination by a ground-based nuclear burst detection system

Description: Sandia Laboratories is developing for the U.S. Army a Ground-Based Nuclear Burst Detection System to provide pertinent information for its field commanders and higher authorities. The equipment must operate in all kinds of weather and produce very low false alarms under all types of conditions. With these requirements, a study of the effects during thunderstorms, which includes thousands of lightning flashes, was conducted. The results of these studies were that, with suitable discrimination, the system had no false alarms during a period of high thunderstorm activity in the Albuquerque area for the time from September 13 to October 3, 1977. Data and plots are included of those false alarms that were recorded before the final discriminants were implemented to provide an inventory of waveshapes for additional analysis.
Date: April 1, 1978
Creator: Thornbrough, A.D.
Partner: UNT Libraries Government Documents Department

Processing of seismic signals for pattern recognition

Description: The study describes the preparation of seismic signals in order to identify the best technique for input to a pattern recognition scheme. The signal is first filtered with zero phase shift high and low pass Butterworth filters. It is then subjected to adaptive filtering and finally moving average filtering. Spectral decomposition in terms of circular functions is done via conventional Fourier and log P maximum entropy analysis. Spectral decomposition in terms of sequency functions, Walsh, and Chebyshev, is also performed. The Walsh decomposition is done with the conventional fast operator. The Chebyshev decomposition is done with an optimization procedure. Results, based on these various operations, are presented for an underground nuclear explosion and several earthquakes.
Date: January 1, 1978
Creator: Brolley, J.E.
Partner: UNT Libraries Government Documents Department

Microwave interferometry to elucidate shock properties

Description: A series of measurements have been performed using a simple, light weight, inexpensive, compact K-Band (SLICK) interferometer to measure the shock properties of passive (Teflon, grout) and energetic (HE) materials. Shock and particle velocity measurements are made simultaneously along the same path. This path is determined by either a thin walled (1/2 mil aluminum foil) waveguide embedded in the material or the caustic of a Teflon axicon. Typically the velocities are determined to about a percent. The measurements will be described and data presented.
Date: September 1, 1993
Creator: Luther, G. G. & Warthen, B. J.
Partner: UNT Libraries Government Documents Department

Single-station locations of seismic events

Description: This report describes the progress being made in event location using a single 3-component station. In this study locations are obtained using a backazimuth determined by the particle motion of Pn and a distance determined by differential travel times between Pn, Pg, and Lg relative to a master event of known location. The data set used consists of the seismic signals from 11 nuclear events at the Nevada Test Site (NTS) and recorded at the four Lawrence Livermore National Laboratory (LLNL) seismic stations: Elko, Kanab, Landers, and Mina. The stations range from 230 km to 400 km away from the events. The local magnitude (M/sub L/) of the events range from 3.7 to 5.6 with the small events barely visible over the microseisms. All calculations and observations are made after the events have been filtered between 0.3 and 6 Hz. The results of this analysis show that backazimuth can be determined to within +- 5/sup 0/ of the true backazimuth, about 90% of the time, after systematic variations are taken out.
Date: November 19, 1982
Creator: Burr, N.
Partner: UNT Libraries Government Documents Department

Surface and body waves from surface and underground explosions

Description: The characteristics of surface and ground waves were recorded for surface and underground explosions up to 100 tons and 40 kt in magnitude, respectively, and a preliminary analysis of these results is presented. The experiments were conducted at NTS in the Yucca Flats, Nevada. Ground motions were detected with triaxial geophones along seismic lines extending up to 16 miles from the point of explosions. A comparison of Rayleigh waves generated by surface and underground explosions in the same lake bed is presented indicating a very different behavior of surface and ground waves from the two types of explosions. The magnitude of the transverse wave for surface shots was smaller by a factor of two than its longitudinal counterpart. The dependence of apparent periods on the blast energy was not apparent at a fixed distance from the explosions. Changes in the apparent period with distance for both types of explosion are compared indicating a strong layering effect of the lake bed. The ground motion study was complimented by excavation of cavities generated by the explosions.
Date: June 1, 1976
Creator: Kusubov, A. S.
Partner: UNT Libraries Government Documents Department

Mining-induced seismicity at the Lucky Friday Mine: Seismic events of magnitude >2.5, 1989--1994

Description: An understanding of the types of seismic events that occur in a deep mine provides a foundation for assessing the seismic characteristics of these events and the degree to which initiation of these events can be anticipated or controlled. This study is a first step toward developing such an understanding of seismic events generated by mining in the Coeur d`Alene Mining District of northern Idaho. It is based on information developed in the course of a long-standing rock burst research effort undertaken by the U. S. Bureau of Mines in cooperation with Coeur d`Alene Mining District mines and regional universities. This information was collected for 39 seismic events with local magnitudes greater than 2.5 that occurred between 1989 and 1994. One of these events occurred, on average, every 8 weeks during the study period. Five major types of characteristic events were developed from the data; these five types describe all but two of the 39 events that were studied. The most common types of events occurred, on average, once every 30 weeks. The characteristic mechanisms, first-motion patterns, damage patterns, and relationships to mining and major geologic structures were defined for each type of event. These five types of events need to be studied further to assess their ability to camouflage clandestine nuclear tests as well as the degree to which they can be anticipated and controlled.
Date: September 1, 1996
Creator: Whyatt, J.K.; Williams, T.J.; Blake, W.; Sprenke, K. & Wideman, C.
Partner: UNT Libraries Government Documents Department

Predictions of acoustic signals from explosions above and below the ocean surface: source region calculations

Description: In support of the Comprehensive Test Ban, research is underway on the long range propagation of signals from nuclear explosions in the deep underwater sound (SOFAR) channel. This first phase of our work at LLNL on signals in the source regions considered explosions in or above the deep (5000 m) ocean. We studied the variation of wave properties and source region energy coupling as a function of height or depth of burst. Initial calculations on CALE, a two-dimensional hydrodynamics code developed at LLNL by Robert Tipton, were linked at a few hundred milliseconds to a version of NRL`s weak shock code, NPE, which solves the nonlinear progressive wave equation. The wave propagation simulation was performed down to 5000 m depth and out to 10,000 m range. We have developed a procedure to convert the acoustic signals at 10 km range into `starter fields` for calculations on a linear acoustics code which will extend the propagation to ocean basin distances. Recently we have completed calculations to evaluate environmental effects (shallow water, bottom interactions) on signal propagation. We compared results at 25 km range from three calculations of the same I kiloton burst (50 m height-of-burst) in three different environments, namely, deep water, shallow water, and a case with shallow water sloping to deep water. Several results from this last `sloping bottom` case will be 2016 discussed below. In this shallow water study, we found that propagation through shallow water complicates and attenuates the signal; the changes made to the signal may impact detection and discrimination for bursts in some locations.
Date: December 1, 1996
Creator: Clarke, D.B.; Piacsek, A. & White, J.W.
Partner: UNT Libraries Government Documents Department

Rummy high-altitude pressure measurements and analysis

Description: Five pressure-measurement canisters equipped with parachutes were deployed from an A7C aircraft on the Rummy test. Their altitudes above Yucca flat were over 8.5 km when the pressure pulse arrived. Three successful measurements were obtained. These time histories showed a more complicated behavior than histories obtained on Pahute Mesa tests because the Rummy event developed double spall closures over a large area. Excellent agreement was obtained between the observed pressure histories and those calculated from surface acceleration measurements. The Yucca Flat terrain was so level that pressure pulses were not appreciably changed or weakened by elevation differences.
Date: January 1, 1982
Creator: Banister, J.R. & Hereford, W.V.
Partner: UNT Libraries Government Documents Department

Optimum frequencies for regional detection of cavity-decoupled explosions

Description: The natures of compressional (P) waves that originate in the crust, propagate in the crust and upper mantle, and are observed as Pg, Pn, and anti P waves at regional distances are examined. The discussion includes the observed variations of amplitude with epicentral distance for these waves as well as an estimate of values for the specific dissipation function Q/sub ..cap alpha../ in different regions. Studies were made on theoretical source and propagation functions for direct, reflected, and head waves as approximations for the observed Pg, anti P, and Pn, respectively. It was concluded that the classical (critically refracted) head wave is not very significant in regional observations, and that the related interference head wave and diving wave are more likely observed as Pn. Using an assumed seismic noise spectrum and the constant Q/sub ..cap alpha../ model for seismic attenuation, relations were derived for the frequencies corresponding to maximum signal-to-noise ratio for the classical and interference head waves and for the direct, reflected, and diving waves. The relations among seismic frequency, epicentral distance, anelastic attenuation, and explosion yield are illustrated for a simple source and propagation model.
Date: March 21, 1979
Creator: Rodean, H.C.
Partner: UNT Libraries Government Documents Department

Spherical wave propagation in elastic media and its application to energy coupling for tamped and decoupled explosions

Description: The effects of variation in source and medium properties upon near- and far-field spectra for elastic waves are examined theoretically by considering spherical wave propagation in unbounded elastic media. This type of analysis, although idealized, provides insight into the relative effects of the various source and medium parameters on both tamped and decoupled explosions. It also provides a basis for interpreting both field and laboratory experimental data obtained during spherical wave propagation in real media. In this paper I attempt to unify the work that has been done on spherical wave propagation in elastic media. I present the results in nondimensional forms, in hopes that others may find these forms of the solutions useful and some of the conclusions, based upon my parameter studies, enlightening. Also included is a discussion of some of the limitations of the theory and examples of applications of the spherical wave propagation theory in real media.
Date: January 26, 1979
Creator: Larson, D.B.
Partner: UNT Libraries Government Documents Department

Numerical model of electromagnetic scattering off a subterranean 3-dimensional dielectric

Description: As part of the effort to develop On-Site Inspection (OSI) techniques for verification of compliance to a Comprehensive Test Ban Treaty (CTBT), a computer code was developed to predict the interaction of an electromagnetic (EM) wave with an underground cavity. Results from the code were used to evaluate the use of surface electromagnetic exploration techniques for detection of underground cavities or rubble-filled regions characteristic of underground nuclear explosions.
Date: August 1, 1983
Creator: Dease, C.G. & Didwall, E.M.
Partner: UNT Libraries Government Documents Department

Comparison of the non-proliferation event aftershocks with other Nevada Test Site events

Description: As part of a larger effort to develop technology for on-site inspection of ambiguous underground seismic events, we have been working to identify phenomenology of aftershock seismicity which would be useful for discriminating between nuclear explosions, chemical explosions, earthquakes or other seismic events. Phenomenology we have investigated includes; the spatial distribution of aftershocks, the number of aftershocks as a function of time after the main event, the size of the aftershocks, and waveform frequency content. Our major conclusions are: (1) Depending on local geologic conditions, aftershock production rate two weeks after zero time ranges from 1 to 100 per day. (2) Aftershocks of concentrated chemical explosions such as the NPE are indistinguishable from aftershocks of nuclear explosions. (3) Earthquake and explosion aftershock sequences may be differentiated on the basis of depth, magnitude, and in some cases, frequency content of seismic signals.
Date: April 1, 1994
Creator: Jarpe, S.; Goldstein, P. & Zucca, J. J.
Partner: UNT Libraries Government Documents Department

The Non-Proliferation Experiment recorded at the Pinedale. Seismic research facility

Description: The Non-Proliferation Experiment was recorded by five different seismic stations operated by Sandia National Laboratories at the Pinedale Seismic Research Facility, approximately 7.60 from the Nevada Test Site. Two stations are different versions of the Deployable Seismic Verification System developed by the Department of Energy to provide seismic data to verify compliance with a Comprehensive Test Ban Treaty. Vault and borehole versions of the Designated Seismic Stations also recorded the event. The final station is test instrumentation located at depths of 10, 40 and 1200 feet. Although the event is seen clearly at all the stations, there are variations in the raw data due to the different bandwidths and depths of deployment. One Deployable Seismic Verification System has been operating at Pinedale for over three years and in that time recorded 14 nuclear explosions and 4 earthquakes from the Nevada Test Site, along with numerous other western U.S. earthquakes. Several discriminants based on the work by Taylor et al. (1989) have been applied to this data. First the discriminants were tested by comparing the explosions only to the 4 earthquakes located on the Test Site. Only one discriminant, log(L{sub g}/P{sub g}), did not show clear separation between the earthquakes and nuclear explosions. When other western U.S. events are included, only the m{sub b} vs. M{sub s} discriminant separated the events. In all cases where discrimination was possible, the Non-Proliferation Experiment was indistinguishable from a nuclear explosion.
Date: June 1, 1994
Creator: Carr, D. B.
Partner: UNT Libraries Government Documents Department

Continental seismic events observed by the MPL vertical DIFAR array

Description: The vertical DIFAR array, an underwater acoustic sensor system, deployed by the Marine Physical Laboratory (MPL) was in place over the continental shelf off of Southern California and recorded the HUNTERS TROPHY nuclear test and nearly a score of after-shocks of the Landers/Big Bear earthquakes. Data from this array raise the possibility that detection thresholds for continental events may be significantly lower for arrays over the continental shelf than for arrays in the deep ocean basins. Offshore stations could be used to fill gaps in land-based seismic networks for monitoring the NPT and a CTBT, especially for monitoring non-cooperating nations with large coastlines. This preliminary report provides an analysis of the HUNTERS TROPHY observation as well as one of the Landers aftershocks. The analysis suggests detection thresholds for vertical hydrophone arrays below mb 3.0 at ranges between 3 and 4 degrees, and below mb 4.4 out to 6 degrees. This report also describes two signal processing techniques that enhance the detection potential of short vertical arrays. These methods are deterministic null steering to suppress horizontally propagating ambient ocean noise, and matched field processing for vertically-incident acoustic fields. The latter technique is ideally suited for acoustic fields derived from incident seismic waves, and may be viewed as a {open_quotes}synthetic aperture{close_quotes} approach to increase the effective aperture of the array.
Date: November 1, 1993
Creator: Harris, D. B. & D`Spain, G.
Partner: UNT Libraries Government Documents Department

Modelling of nuclear explosions in hard rock sites

Description: This study represents part of a larger effort to systematically model the effects of differing source region properties on ground motion from underground nuclear explosions at the Nevada Test Site. In previous work by the authors the primary emphasis was on alluvium and both saturated and unsaturated tuff. We have attempted to model events on Pahute Mesa, where either the working point medium, or some of the layers above the working point, or both, are hard rock. The complex layering at these sites, however, has prevented us from drawing unambiguous conclusions about modelling hard rock. In order to learn more about the response of hard rock to underground nuclear explosions, we have attempted to model the PILEDRIVER event. PILEDRIVER was fired on June 2, 1966 in the granite stock of Area 15 at the Nevada Test Site. The working point was at a depth of 462.7 m and the yield was determined to be 61 kt. Numerous surface, sub-surface and free-field measurements were made and analyzed by SRI. An attempt was made to determine the contribution of spall to the teleseismic signal, but proved unsuccessful because most of the data from below-shot-level gauges was lost. Nonetheless, there is quite a bit of good quality data from a variety of locations. We have been able to obtain relatively good agreement with the experimental PILEDRIVER waveforms. In order to do so, we had to model the granodiorite as being considerably weaker than ``good quality`` granite, and it had to undergo considerable weakening due to shock damage as well. In addition, the near-surface layers had to be modeled as being weak and compressible and as have a much lower sound speed than the material at depth. The is consistent with a fractured and jointed material at depth, and a weathered material near the ...
Date: May 1, 1993
Creator: Brunish, W. M. & App, F. N.
Partner: UNT Libraries Government Documents Department

User manual for the NTS ground motion data base retrieval program: ntsgm

Description: The NTS (Nevada Test Site) Ground Motion Data Base is composed of strong motion data recorded during the normal execution of the US underground test program. It contains surface, subsurface, and structure motion data as digitized waveforms. Currently the data base contains information from 148 underground explosions. This represents about 4,200 measurements and nearly 12,000 individual digitized waveforms. Most of the data was acquired by Los Alamos National Laboratory (LANL) in connection with LANL sponsored underground tests. Some was acquired by Los Alamos on tests conducted by the Defense Nuclear Agency (DNA) and Lawrence Livermore National Laboratory (LLNL), and there are some measurements that were acquired by the other test sponsors on their events and provided for inclusion in this data base. Data acquisition, creation of the data base, and development of the data base retrieval program (ntsgm) are the result of work in support of the Los Alamos Field Test Office and the Office of Nonproliferation and Arms Control.
Date: May 1, 1994
Creator: App, F. N. & Tunnell, T. W.
Partner: UNT Libraries Government Documents Department

Elements of a system for verifying a Comprehensive Test Ban

Description: The paper discusses the goals of a monitoring system for a CTB, its functions, the challenges to verification, discrimination techniques, and some recent developments. It is concluded technical, military and political efforts are required to establish and verify test ban treaties which will contribute to stability in the long term. It currently appears there will be a significant number of unidentified events. (ACR)
Date: March 6, 1987
Creator: Hannon, W.J.
Partner: UNT Libraries Government Documents Department

User`s manual for the CDC-1 digitizer controller

Description: A detailed description of how to use the CDC-1 digitizer controller is given. The CDC-1 is used with the CAMAC format digitizer models in the TRAQ series (manufactured by DSP Technology Inc.), the DAD-1 data acquisition daughter board, and the Intel i860-based SuperCard-2 (manufactured, by CSP Inc.) to form a high speed data acquisition and real time analysis system. Data can be transferred to the memory on the SuperCard-2 at a rate as high as 40 million 14-bit samples per second. Depending on the model of TRAQ digitizer in use, digitizing rates up to 3.33 MHz are supported (with eight data channels), or, for instance, at a sample rate of 100 kHz, 384 data channels can be acquired.
Date: September 1, 1994
Creator: Ferron, J. R.
Partner: UNT Libraries Government Documents Department