Regional Surface Wave Magnitude and Moment Determination Methods Applied to Nuclear Explosions at the Nevada Test Site PDF Download

Author: Bradley B. Woods
Publisher:
ISBN:
Category : Earthquake hazard analysis
Languages : en
Pages : 214

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Author: Bradley B. Woods
Publisher:
ISBN:
Category :
Languages : en
Pages : 8

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Seismic moments of Nevada Test Site (NTS) explosions were determined from regional surface wave spectra. Two methods were used. In one the moment is solved for assuming only an explosive source, or average scalar moment; in the other a joint inversion for an isotropic (explosive) source plus a constrained double couple moment component representing tectonic strain release (TSR). Although the general moment tensor solution to this joint inversion problem is non-unique, if some assumptions are made concerning the non-isotropic moment components, then the remaining source parameters can be solved by a linear least-squares inversion scheme. We examined the errors in determining the isotropic moment component (M sub I) by this latter method of constrained linear inversion solutions in a canonical study using a theoretical network of long-period (6-60 sec.) surface wave data. The network azimuthal coverage was chosen to represent that of a long-period North American super-network of 55 stations used for the actual NTS events. We compared these errors in moment estimate to those obtained from surface wave magnitude (M sub s) and spectral scalar moment (M sub 0) measurements for the same surface wave observations. For a ratio of M sub expl/M sub eq less than 1.0 we found that the inverted M sub I solution is a much better estimate of the actual isotropic moment than either M sub s or M sub O, and the standard deviation in this estimate is substantially less than that using the other two methods for the great majority of isotropic source + double couple sources. Even when the inversion constraints are off in dip and rake each by 30 deg, the mis-estimate of the isotropic moment is less than 35 percent of the actual value.

Author:
Publisher:
ISBN:
Category : Nuclear arms control
Languages : en
Pages : 156

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Author: Norman A. Haskell
Publisher:
ISBN:
Category : Atomic bomb
Languages : en
Pages : 42

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Author:
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ISBN:
Category :
Languages : en
Pages : 24

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Regional seismic explosion monitoring requires the discrimination of small clandestine nuclear explosions from background earthquakes. most successful teleseismic discriminant, the so-called Ms:mb, discriminant, compares the long-period surface waves magnitude (Ms) with the period P-based body wave magnitude (mb). There are many studies underway to try and extend surface wave magnitude (Ms) estimation to re distances and smaller magnitudes. Another problem that is encountered is how to estimate mb so that the Ms:mb discriminant is meaningful a consistent with teleseismic measures. For small-to-moderate sized events, the teleseismic body wave magnitude, mb(P), cannot be effectively measured due to low signal-to-noise ratio. We develop a stable regional alternative based on the P-coda that scales 1-to-1 with the teleseismic mb(P), but with the advantage of lower variance. Though mb(Lg) and mb(Lg-coda) can be tied to mb(P) for explosions, they overpredict earth magnitudes by ~0.5-1 magnitude units and degrade the performance of the Ms:mb discriminant. In contrast, mb(P-coda) does not exhibit this and can be used to extend Ms:mb to smaller regional events.

Author: National Research Council
Publisher: National Academies Press
ISBN: 0309174503
Category : Political Science
Languages : en
Pages : 150

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On September 24, 1996, President Clinton signed the Comprehensive Nuclear Test Ban Treaty at the United Nations Headquarters. Over the next five months, 141 nations, including the four other nuclear weapon statesâ€"Russia, China, France, and the United Kingdomâ€"added their signatures to this total ban on nuclear explosions. To help achieve verification of compliance with its provisions, the treaty specifies an extensive International Monitoring System of seismic, hydroacoustic, infrasonic, and radionuclide sensors. This volume identifies specific research activities that will be needed if the United States is to effectively monitor compliance with the treaty provisions.

Author: Anatoli L. Levshin
Publisher: Springer
ISBN: 3034882645
Category : Science
Languages : en
Pages : 260

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On September 1996, the United Nations General Assembly adopted the Comprehensive Nuclear-Test-Ban Treaty (CTBT), prohibiting nuclear explosions worldwide, in all environments. The treaty calls for a global verification system, including a network of 321 monitoring stations distributed around the globe, a data communications network, an international data center (IDC), and on-site inspections to verify compliance. Seismic methods play the lead role in monitoring the CTBT. This volume concentrates on the measurement and use of surface waves in monitoring the CTBT. Surface waves have three principal applications in CTBT monitoring: to help discriminate nuclear explosions from other sources of seismic energy, to provide mathematical characterizations of the seismic energy that emanates from seismic sources, and to be used as data in inversion for the seismic velocity structure of the crust and uppermost mantle for locating small seismic events regionally. The papers in this volume fall into two general categories: the development and/or application of methods to summarize information in surface waves, and the use of these summaries to advance the art of surface-wave identification, measurement, and source characterization. These papers cut across essentially all of the major applications of surface waves to monitoring the CTBT. This volume therefore provides a general introduction to the state of research in this area and should be useful as a guide for further exploration.

Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 912

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Author: Haruo Sato
Publisher: Springer Science & Business Media
ISBN: 3540896236
Category : Science
Languages : en
Pages : 308

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Seismic waves – generated both by natural earthquakes and by man-made sources – have produced an enormous amount of information about the Earth's interior. In classical seismology, the Earth is modeled as a sequence of uniform horizontal layers (or sperical shells) having different elastic properties and one determines these properties from travel times and dispersion of seismic waves. The Earth, however, is not made of horizontally uniform layers, and classic seismic methods can take large-scale inhomogeneities into account. Smaller-scale irregularities, on the other hand, require other methods. Observations of continuous wave trains that follow classic direct S waves, known as coda waves, have shown that there are heterogeneities of random size scattered randomly throughout the layers of the classic seismic model. This book focuses on recent developments in the area of seismic wave propagation and scattering through the randomly heterogeneous structure of the Earth, with emphasis on the lithosphere. The presentation combines information from many sources to present a coherent introduction to the theory of scattering in acoustic and elastic materials and includes analyses of observations using the theoretical methods developed.

Author:
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ISBN:
Category :
Languages : en
Pages :

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We have estimated the seismic moment for two Nevada Test Site (NTS) explosions (Nebbiolo, 6/24/82; Atrisco, 8/5/82) at the Regional Seismic Test Network (RSTN) station in South Dakota (RSSD; distance from NTS approx. 1280 km). The moments are calculated from the vertical component mid-period channel for the Rayleigh waves and the merged mid- and short-period band for the P waves. The moment estimates from surface waves give values of 1.0 x 1023 and 2.0 x 1023 dyn-cm for Nebbiolo and Atrisco, respectively. The body-wave moments obtained at 0.5 Hz are approximately five times greater than those from surface waves and give values of 4.8 x 1023 and 1.0 x 1024 dyn-cm for Nebbiolo and Atrisco, respectively. The apparent discrepancy between the body and surface-wave moments can be resolved if there is overshoot (of 5:1) in the explosion source spectrum. As a check on the absolute value of the surface-wave moments, we compared them to moment values predicted from empirical moment-yield relationships for different emplacement media at NTS (Patton, 1983). We found that the agreement between observed and predicted values is satisfactory, within the measurement error on the moments at the one sigma level.