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Regional Discrimination Of Quarry Blasts Earthquakes And Underground Nuclear Explosions
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Book Synopsis Regional Discrimination of Quarry Blasts, Earthquakes and Underground Nuclear Explosions by : T. J. Bennett
Download or read book Regional Discrimination of Quarry Blasts, Earthquakes and Underground Nuclear Explosions written by T. J. Bennett and published by . This book was released on 1989 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigations conducted under this contract focused on analyses of the higher-frequency phases observed at regional distances from underground nuclear explosions, earthquakes, and commercial blasts. These analyses systematically compared the time-domain amplitude and spectral characteristics of the observed regional seismic signals in order to identify diagnostic differences which would be indicative of source type. The sources were located in three tectonic environments: (1) eastern North America, (2) southern Soviet Union, and (3) western United States. Each source environment provides a unique contribution to the regional discrimination problem. For these source regions digital data from several different high-quality seismic networks were analyzed. The data sources were the Regional Seismic Test Network (RSTN), the Eastern Canada Telemetered Network (ECTN), the Chinese Digital Seismic Network (CDSN), the Soviet/Natural Resources Defense Council (NRDC) network, and the Lawrence Livermore National Laboratory (LLNL) network. (jhd).
Book Synopsis Discriminating Underground Explosions from Earthquakes Using Seismic Coda Waves by :
Download or read book Discriminating Underground Explosions from Earthquakes Using Seismic Coda Waves written by and published by . This book was released on 1995 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: We successfully discriminated quarry blasts and earthquakes at local distance from the observed source power spectra by using the coda Q method. To extend this discrimination method to events at regional distances, we developed the energy transfer theory for a mixture of Rayleigh and S wave propagation in a random scattering and attenuation medium. Applying this theory to the quarry blast earthquake problem at local distance, we can explain the observations satisfactorily. Our study indicates that Rayleigh wave scattering become important for events with shallow focal depth, such as quarry blasts and nuclear explosions. By fitting our, theoretical attenuation curves to observed ones at local distances, we have obtained the S and Rayleigh wave S intrinsic and scattering coefficients, and the coupled scattering coefficient of Rayleigh with S waves. Assuming that these coefficients are valid for events at regional distances, we have compared the predicted and observed coda envelope at regional distances for the purpose of discrimination between earthquakes and explosions. Our prediction shows that the Rayleigh wave S contributions become more significant for shallower events (explosions), while for deeper events (earthquakes), the Rayleigh wave's contributions are still negligible. Comparison between predicted and the data of CDSN suggests that the discrimination of earthquakes and explosions at regional distance may be possible by using the coda method for the high frequency case. For the low frequency case, we must consider the crustal effects. (MM).
Book Synopsis REGIONAL SEISMIC CHEMICAL AND NUCLEAR EXPLOSION DISCRIMINATION by : V. Johnson
Download or read book REGIONAL SEISMIC CHEMICAL AND NUCLEAR EXPLOSION DISCRIMINATION written by V. Johnson and published by . This book was released on 2006 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: We continue exploring methodologies to improve regional explosion discrimination using the western U.S. as a natural laboratory. The western U.S. has abundant natural seismicity, historic nuclear explosion data, and widespread mine blasts, making it a good testing ground to study the performance of regional explosion discrimination techniques. We have assembled and measured a large set of these events to systematically explore how to best optimize discrimination performance. Nuclear explosions can be discriminated from a background of earthquakes using regional phase (Pn, Pg, Sn, Lg) amplitude measures such as high frequency P/S ratios. The discrimination performance is improved if the amplitudes can be corrected for source size and path length effects. We show good results are achieved using earthquakes alone to calibrate for these effects with the MDAC technique (Walter and Taylor, 2001). We show significant further improvement is then possible by combining multiple MDAC amplitude ratios using an optimized weighting technique such as Linear Discriminant Analysis (LDA). However this requires data or models for both earthquakes and explosions. In many areas of the world regional distance nuclear explosion data is lacking, but mine blast data is available. Mine explosions are often designed to fracture and/or move rock, giving them different frequency and amplitude behavior than contained chemical shots, which seismically look like nuclear tests. Here we explore discrimination performance differences between explosion types, the possible disparity in the optimization parameters that would be chosen if only chemical explosions were available and the corresponding effect of that disparity on nuclear explosion discrimination. Even after correcting for average path and site effects, regional phase ratios contain a large amount of scatter. This scatter appears to be due to variations in source properties such as depth, focal mechanism, stress drop, in the near source material properties (including emplacement conditions in the case of explosions) and in variations from the average path and site correction. Here we look at several kinds of averaging as a means to try and reduce variance in earthquake and explosion populations and better understand the factors going into a minimum variance level as a function of epicenter (see Anderson ee et al. this volume). We focus on the performance of P/S ratios over the frequency range from 1 to 16 Hz finding some improvements in discrimination as frequency increases. We also explore averaging and optimally combining P/S ratios in multiple frequency bands as a means to reduce variance. Similarly we explore the effects of azimuthally averaging both regional amplitudes and amplitude ratios over multiple stations to reduce variance. Finally we look at optimal performance as a function of magnitude and path length, as these put limits the availability of good high frequency discrimination measures.
Book Synopsis Regional Seismic Discrimination Optimization With and Without Nuclear Test Data by : W. R. Walter
Download or read book Regional Seismic Discrimination Optimization With and Without Nuclear Test Data written by W. R. Walter and published by . This book was released on 2005 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The western U.S. has abundant natural seismicity, historic nuclear explosion data, and widespread mine blasts, making it a good testing ground to study the performance of regional source-type discrimination techniques. We have assembled and measured a large set of these events to systematically explore how to best optimize discrimination performance. Nuclear explosions can be discriminated from a background of earthquakes using regional phase (Pn, Pg, Sn, Lg) amplitude measures such as high frequency P/S ratios. The discrimination performance is improved if the amplitudes can be corrected for source size and path length effects. We show good results are achieved using earthquakes alone to calibrate for these effects with the MDAC technique (Walter and Taylor, 2001). We show significant further improvement is then possible by combining multiple MDAC amplitude ratios using an optimized weighting technique such as Linear Discriminant Analysis (LDA). However this requires data or models for both earthquakes and explosions. In many areas of the world regional distance nuclear explosion data is lacking, but mine blast data is available. Mine explosions are often designed to fracture and/or move rock, giving them different frequency and amplitude behavior than contained chemical shots, which seismically look like nuclear tests. Here we explore discrimination performance differences between explosion types, the possible disparity in the optimization parameters that would be chosen if only chemical explosions were available and the corresponding effect of that disparity on nuclear explosion discrimination. There are a variety of additional techniques in the literature also having the potential to improve regional high frequency P/S discrimination. We explore two of these here: three-component averaging and maximum phase amplitude measures. Typical discrimination studies use only the vertical component measures and for some historic regional nuclear records these are all that are available. However S-waves are often better recorded on the horizontal components and some studies have shown that using a three-component average or a vertical-P/horizontal-S or other three-component measure can improve discrimination over using the vertical alone (e.g. Kim et al. 1997; Bowers et al 2001). Here we compare the performance of vertical and three-component measures on the western U.S. test set. A complication in regional discrimination is the variation in P and S-wave propagation with region. The dominantly observed regional high frequency S-wave can vary with path between Sn and Lg in a spatially complex way. Since the relative lack of high frequency S-waves is the signature of an explosion, failing to account for this could lead to misidentifying an earthquake as an explosion. The regional P phases Pn and Pg vary similarly with path and also with distance, with Pg sometimes being a strong phase at near regional distances but not far regional. One way to try and handle these issues is to correct for all four regional phases but choose the phase with the maximum amplitude. A variation on this strategy is to always use Pn but choose the maximum S phase (e.g. Bottone et al. 2002). Here we compare the discrimination performance of several different (max P)/(max S) measures to vertical, three-component and multivariate measures. Our preliminary results show that multivariate measures perform much better than single ratios, though transportability of the LDA weights between regions is an issue. Also in our preliminary results, we do not find large discrimination performance improvements with three-component averages and maximum phase amplitude measures compared to using the vertical component alone.
Book Synopsis Seismic Discrimination Between Earthquakes and Explosions in the Middle East and North Africa by :
Download or read book Seismic Discrimination Between Earthquakes and Explosions in the Middle East and North Africa written by and published by . This book was released on 1997 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recently signed Comprehensive Test Ban Treaty provides for an international network of primary and auxiliary seismic monitoring stations (IMS) to verify its compliance. Calibration is required to confidently use these stations to identify and discriminate between earthquakes, mine-related events and clandestine nuclear explosions, particularly for small to moderate seismic events recorded regionally at only a few stations. Given the lack of regional recordings of underground nuclear tests in most of the world, we are making use of mining and industrial explosions to test discriminants. For example we use the Multimax compiled dataset of small earthquakes and quarry explosions in Israel to test regional discriminants at local distances with mixed results. Further complicating calibration is the fact that many INK sites have not yet been installed and others have very short operating histories. When IMS data is available, there is often a lack of independent information (ground truth) on the seismic sources. Here we describe a procedure for calibrating stations with limited data and apply it to the IMS auxiliary station MDT in Morocco. Data was initially available for three months in 1990 when MDT was operated as part of MEDNET. An event detector was run over the continuous data and regional events identified and roughly located using S-P time and back azimuth. The procedure uses spatial and temporal clustering to identify ''known'' mine blasts. The spatial clustering is done using the waveform correlation technique of Harris (1991) to find events with similar sources and locations. Temporal clustering looks at the time of day and repetition in time of events with the mine blasts occurring during working hours and days repeatedly over a period of time. A set of ''known'' earthquakes is also determined using location, time of day, distribution in time and size criteria. With these independent libraries of identified seismic events, we evaluate promising regional discriminants such as high frequency P/Lg. We also examine distance and path effects on the discriminants. Preliminary results indicate high frequency P/Lg provides some separation between mine blasts and earthquakes at MDT.
Book Synopsis RMS Lg Studies of Underground Nuclear Explosions in the U.S.S.R. and the U.S. by : P. G. Richards
Download or read book RMS Lg Studies of Underground Nuclear Explosions in the U.S.S.R. and the U.S. written by P. G. Richards and published by . This book was released on 1993 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Seismic Discrimination of Earthquakes and Explosions, with Application to the Southwestern United States by : D. H. VON Seggern
Download or read book Seismic Discrimination of Earthquakes and Explosions, with Application to the Southwestern United States written by D. H. VON Seggern and published by . This book was released on 1979 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study examines seismic discrimination between underground nuclear explosions and earthquakes in the Southwestern United States. A thorough review of theoretical and applied research on this problem, especially as it relates to that region, is presented first, followed by a presentation of the seismic discrimination parameters computed for a suite of events in the Southwest and a series of experiments with multi-dimensional discrimination. Review of past work finds some theoretical support for successful discrimination based upon several distinct measurements on seismic recordings. Although negative first motion and presence of pP both indicate a natural earthquake source, they cannot be found confidently in many cases. The relative level of shear-wave and Love-wave phases should be a good classification parameter. The long-period P spectrum of explosions should be diminished due to the surface interaction and consequent cancellation by pP. The region under study extends from California to the southern Rocky Mountains and from roughly 40 degrees N to the Gulf of California. A region of high seismicity, it is also a complex region encompassing several tectonic provinces, including the Basin-Range Province where the Nevada Test Site is located. In general, seismic discriminant parameters obtained from the recordings reflected the theoretical expectations of earthquake-explosion differences. Path-station effects were large for every parameter, especially for short-period data.
Book Synopsis Chemical Explosions and the Discrimination Problem by :
Download or read book Chemical Explosions and the Discrimination Problem written by and published by . This book was released on 1991 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is in three sections: Section one describes empirical estimates of yield and tectonic release for 71 underground nuclear explosions conducted at the Shagan River Test Site, Kazakhstan, from 1977 to 1989. The method is based upon teleseismic observations of fundamental mode Love and Rayleigh waves at stations of the GDSN, CDSN, RSTN, and IRIS/USGS GSN. In 1977 as few as five stations were providing data, while in the late 1980's more than 25 stations were operational. Section two makes a case for generating lists of problems events - seismic sources whose signals cannot easily be discriminated - as a mechanism for achieving three goals: (1) encouraging seismologists to contribute data that may help to discriminate events listed; (2) training; and (3) helping to build consensus in the technical community, on what types of problem events are truly intractable with current data Section three describes spectral-temporal characteristics of regional seismograms and shows how they can be used to discriminate between different types of seismic sources. We analyze the high-frequency (1-40 hz) spectral of chemical explosions and earthquakes at local and regional distances to understand the seismic signal characteristics of different types of sources and to find stable discriminators. We evaluate the application of the spectrogram technique to regional seismograms in different geologic settings using data from single explosions, multiple-hole instantaneous explosions, ripple-fired quarry blasts, and earthquakes. The effects on high frequency spectra of local source and recorder site conditions and source to receiver path are also analyzed.
Book Synopsis Discrimination Underground Explosions from Earthquakes Using Seismic Coda Waves by :
Download or read book Discrimination Underground Explosions from Earthquakes Using Seismic Coda Waves written by and published by . This book was released on 1994 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study is to discriminate the explosions and earthquakes at regional distance by using the coda wave method. In an earlier study, Su and Aki (1991) found a significant difference in coda attenuation, Qc- 1, for quarry blasts and earthquakes at frequencies of 1.5 and 3 Hz for lapse time less than 30 seconds and they suggested that such a significant difference in Qc-1 may be attributed to the seismic surface wave's contributions. To interpret the observed seismic coda waves we need to consider the seismic surface wave scattering processes. Wu (1985) and Zeng et al. (1991, 1993) have shown that the energy transfer theory can successfully describe the seismic body waves scattering processes in a random scattering and absorption full-space medium. In this study, we shall first use the energy transfer equations to study the seismic surface waves scattering processes and the surface wave with body waves scattering processes in order to interpret the Su and Aki's observed results. We shall then extend this method to study the explosions and earthquakes at regional distance.
Book Synopsis Regional Discrimination Research and Methodology Implementation: Analyses of CDSN and Soviet IRIS Data by :
Download or read book Regional Discrimination Research and Methodology Implementation: Analyses of CDSN and Soviet IRIS Data written by and published by . This book was released on 1990 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research is to evaluate the capability of regional stations in discrimination of underground nuclear explosions from earthquakes and non-nuclear explosions. Efforts during the first year of this program have focused on studies of regional data from the Chinese Digital Seismic Network(CDSN) and Incorporated Research Institutions for Seismology(IRIS) stations in the Soviet Union. A previous report described observations from the CDSN station at WMQ which indicated differences in relative spectral content of Lg versus regional P for explosions and earthquakes. In the current research we used different spectral analyses to study the signals from a larger event sample including 27 East Kazakh explosions and 32 regional earthquakes. Lg/P ratios for regional earthquakes were found to be enriched at high frequencies compared to similar explosions. In comparing explosions from Shagan River and Degelen Mountain areas it was found that regional P signals are relatively stronger from SR than from DM explosions with similar Lg signals. Analysis of East Kazakh explosion signals recorded at Soviet IRIS stations indicates that regional signals are observable down to very low magnitudes. Lg magnitude residuals from these stations have been used to derive effective Q values for these paths.
Book Synopsis Estimating Characteristics of Chemical Explosions in New England and Eastern Kazakhstan Using Local and Regional Seismic Data by : A. L. Kafka
Download or read book Estimating Characteristics of Chemical Explosions in New England and Eastern Kazakhstan Using Local and Regional Seismic Data written by A. L. Kafka and published by . This book was released on 1989 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the problems associated with monitoring a comprehensive nuclear test ban treaty is that of discrimination between small explosions and earthquakes based on seismic data. Chemical explosions are used routinely in the mining and construction industries in both the United States and the Soviet Union. These chemical explosions usually occur at very shallow depths (a few tens of feet), and probably are all shallower than a few hundred meters. Most nuclear explosions are detonated at depths of less than about one kilometer, and the deepest underground nuclear explosions are a few kilimeters deep. On the other hand, most earthquakes occur deeper in the earth's crust. Thus, accurate estimation of the depths of seismic sources can be helpful in discriminating earthquakes from explosions. During the past several years, the Principal Investigator (PI) for this summer project has been studying the use of short-period Rayleigh waves (Rg) as a depth discriminant for seismic sources in New England.
Book Synopsis Investigations Into Seismic Discrimination Between Earthquakes, Chemical Explosions and Nuclear Explosions by :
Download or read book Investigations Into Seismic Discrimination Between Earthquakes, Chemical Explosions and Nuclear Explosions written by and published by . This book was released on 1995 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this report we describe some results of investigations on a problem of discrimination between nuclear explosions, chemical explosions and earthquakes, carried out in the Complex Seismological Expedition of the Joint Institute of Physics of the Earth of the Russian Academy of Sciences. Records of underground nuclear explosions from the Semipalatinsk test site, and from region the Pre-Caspian depression, and also records of nearby chemical explosions and earthquakes were processed. We analysed records of permanent and temporary stations, located mainly in the North Tien Shan, northern Kazakhstan and Urals regions. We studied the influence of regional conditions on the effectiveness of seismic monitoring of nuclear explosions. Various amplitude criteria of the discrimination between explosions and earthquakes are considered. We analyzed possibilities to discriminate different source types using spectral-temporal characteristics of seismograms. The nature of some wave types, recorded at region distances, is investigated. We consider possibilities of discrimination between nuclear and chemical explosions and earthquakes using analysis of characteristics of irregular waves. We outline future investigations, connected with the study of the unique set of seismograms kept in the CSE.
Book Synopsis A Discrimination Analysis of Regional Seismic Data Recorded at Tonto Forest Observatory from Nevada Test Site Explosions and Nearby Earthquakes by : J. R. Murphy
Download or read book A Discrimination Analysis of Regional Seismic Data Recorded at Tonto Forest Observatory from Nevada Test Site Explosions and Nearby Earthquakes written by J. R. Murphy and published by . This book was released on 1981 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The principal objectives of the research reported here are to identify any diagnostic differences between regional seismic phases produced by earthquakes and underground nuclear explosions and to assess their applicability to events occurring in various regions of the U.S.S.R. Two approaches are used: one employs traditional time-domain amplitude and period measurements to compare the relative excitation of various regional phases for earthquakes and explosions, while the second focuses on more sophisticated measurement or processing techniques such as spectral ratios or narrow-band filtering to extract information about frequency differences in the signals generated by the two types of events. The research reported here was directed at identification of discriminants based on measurements of seismic phases at regional distances from a well-controlled set of Western U.S. explosions and nearby earthquakes. The set includes more than 50 Nevada Test Site events (explosions and nearby earthquakes) recorded at the Tonto Forest Observatory in Arizona. The investigation included spectral analyses of the short-period regional phases, Pn, Pg, and Lg which follows-up a previously reported study of time-domain characteristics of these phases. In addition, the current study includes an analysis of the time-domain characteristics of the long-period data from the Nevada Test Site event set, with particular emphasis on the potential applicability of the Ms/mb discriminant to the identification of small events (mb
Book Synopsis Investigation of Regional Seismic Discrimination Issues for Small Or Decoupled Nuclear Explosions by :
Download or read book Investigation of Regional Seismic Discrimination Issues for Small Or Decoupled Nuclear Explosions written by and published by . This book was released on 1994 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goals of lowering the seismic threshold for underground nuclear explosions to magnitudes near 2.5 m sob o and extending the capability to other geographical regions will require utilization of regional stations for detection and identification. However, regional techniques have seldom been tested on small nuclear explosions. Therefore, S-CUBED is conducting a research program aimed at the identification problems associated with small or decoupled nuclear explosions near a low monitoring threshold (e.g. 1-kt fully decoupled or about 2.5 mb). Initial efforts have focused on using source scaling procedures to scale down records from larger explosions and produce representative seismograms at ARPA regional array stations. The scaled signals embedded in typical background noise at the station enable an assessment of capabilities for different regional signal analysis methods at the lower thresholds. Our preliminary findings are that useful far-regional signals from small or decoupled nuclear explosions may be constrained to very limited high-frequency bands, which may limit the capabilities of some regional detection and identification techniques.
Book Synopsis The Influence of Rock Material on Seismic Discrimination of Underground Nuclear Explosions by :
Download or read book The Influence of Rock Material on Seismic Discrimination of Underground Nuclear Explosions written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Cause of the Body-wave Surface-wave Discriminant Between Earthquakes and Underground Nuclear Explosions at Near-regional Distances by : William Alan Peppin
Download or read book The Cause of the Body-wave Surface-wave Discriminant Between Earthquakes and Underground Nuclear Explosions at Near-regional Distances written by William Alan Peppin and published by . This book was released on 1974 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Forensic Explosion Seismology by : So Gu Kim
Download or read book Forensic Explosion Seismology written by So Gu Kim and published by Cambridge Scholars Publishing. This book was released on 2020-03-02 with total page 531 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses three major physical phenomena for active source seismology, namely underwater explosions, underground nuclear explosions, and large-scale on-surface chemical explosions. In particular, contributors consider how to use the technologies and applications in active source seismology and seismo-acoustics, rather than the theoretical approach for the resolution of the forensic explosion seismology in the light of an application for defense sciences. The volume also presents seismological investigations of discrimination between earthquakes and man-made explosions.
