Download or read book Lg Excitation Attenuation and Source Spectral Scaling in Central and Eastern North America written by B. J. Mitchell and published by Nuclear Regulatory Commission. This book was released on 1998-01-01 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lg Excitation Attenuation and Source Spectral Scaling in Central and Eastern North America written by B. J. Mitchell and published by . This book was released on 1997 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lg Excitation Attenuation and Source Spectral Scaling in Central and Eastern North America written by and published by . This book was released on 1997 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic moments and corner frequencies were obtained for many earthquakes in the central and eastern United States, and for a few events in the western United States, using the Lg phase and a recently developed inversion algorithm. Additionally, Q values for the Lg phase along paths to individual stations were obtained simultaneously with the source parameters. Both corner frequencies and magnitudes were found to vary systematically with moment. For moments between 0.15 and 400 x 1015 N-m corner frequencies vary between about 4 and 0.2 Hz while body-wave magnitude varies between about 3.5 and 5.8. A map of Lg Q values displays a systematic decrease from east and west. Maximum and minimum values are 989 and 160, respectively. Lg coda Q values were obtained for the entire United States with excellent coverage in the eastern and western portions of the country and somewhat poorer coverage in the central portion. Lg coda Q is highest (700-750) in a region of the northeastern United States that includes portions of New York and Pennsylvania and lowest (>200) in California. Lg coda Q is lower (250-450) everywhere west of Rocky Mountains than in the rest of the country (450-750). Q determinations for both the direct Lg phase and Lg coda indicate that, for an earthquake of a given magnitude, Lg and its coda will propagate much more efficiently, and cause damage over a wider area, in the eastern and central United States than it will in the United States.

Download or read book Lg Excitation Attenuation and Source Spectral Scaling In Central Asia and China written by and published by . This book was released on 1996 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nonlinear inverse method of Xie (1993) is applied to analyze Lg spectra from 21 underground nuclear explosions and 52 shallow (5-33 km) earthquakes in central Eurasia where, for numerous paths, Lg Q and Lg coda Q at 1 Hz are found to be very similar. The logarithm of Lg seismic moment (Mo) values correlate linearly with body wave magnitude (Mb), with slopes of slightly greater than 1.0. For the same Mo values, the Mb values for earthquakes tend to be systematically lower than those for explosions. For both explosions and earthquakes, Mo scale with fcaa, with fc being Lg corner frequency and a being closer to 4 than to 3. For explosions, the estimated Mo, fc values are dependent on whether the explosion or earthquake source model is used. At any given Mo level, the fc value estimated for an explosion with the earthquake source model tends to be higher than that for an earthquake. This tendency appears to be opposite to that observed at the NTS, and maybe used as an explosion discriminant for central Eurasia.

Download or read book An Introduction to Seismology Earthquakes and Earth Structure written by Seth Stein and published by John Wiley & Sons. This book was released on 2013-05-30 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Introduction to Seismology, Earthquakes and Earth Structures is an introduction to seismology and its role in the earth sciences, and is written for advanced undergraduate and beginning graduate students. The fundamentals of seismic wave propagation are developed using a physical approach and then applied to show how refraction, reflection, and teleseismic techniques are used to study the structure and thus the composition and evolution of the earth. The book shows how seismic waves are used to study earthquakes and are integrated with other data to investigate the plate tectonic processes that cause earthquakes. Figures, examples, problems, and computer exercises teach students about seismology in a creative and intuitive manner. Necessary mathematical tools including vector and tensor analysis, matrix algebra, Fourier analysis, statistics of errors, signal processing, and data inversion are introduced with many relevant examples. The text also addresses the fundamentals of seismometry and applications of seismology to societal issues. Special attention is paid to help students visualize connections between different topics and view seismology as an integrated science. An Introduction to Seismology, Earthquakes, and Earth Structure gives an excellent overview for students of geophysics and tectonics, and provides a strong foundation for further studies in seismology. Multidisciplinary examples throughout the text - catering to students in varied disciplines (geology, mineralogy, petrology, physics, etc.). Most up to date book on the market - includes recent seismic events such as the 1999 Earthquakes in Turkey, Greece, and Taiwan). Chapter outlines - each chapter begins with an outline and a list of learning objectives to help students focus and study. Essential math review - an entire section reviews the essential math needed to understand seismology. This can be covered in class or left to students to review as needed. End of chapter problem sets - homework problems that cover the material presented in the chapter. Solutions to all odd numbered problem sets are listed in the back so that students can track their progress. Extensive References - classic references and more current references are listed at the end of each chapter. A set of instructor's resources containing downloadable versions of all the figures in the book, errata and answers to homework problems is available at: http://levee.wustl.edu/seismology/book/. Also available on this website are PowerPoint lecture slides corresponding to the first 5 chapters of the book.

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1999-07 with total page 1154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Excitation and Propagation of Lg in Central Eurasia written by Lianli Cong and published by . This book was released on 1995 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lg spectra from 20 underground nuclear explosions and 52 shallow earthquakes in central Eurasia have been collected at 21 broad band IRIS, CDSN and KNET stations. Using the non-linear method of Xie (1993), we simultaneously invert for Lg source spectral parameters and path-variable Lg Q sub 0 and eta values (Lg Q at 1 Hz and its power-law frequency dependence, respectively). The inversions yield Lg seismic moments (M sub 0), corner frequencies (f sub c) for the events, as well as Lg Q sub 0 and eta values for numerous paths in central Eurasia. Grossly speaking, Lg Q and Lg coda Q are similar in central Eurasia, although minor discrepancies exist between (a) Lg eta and Lg coda eta at large (>about 2700 km) distances, and (b) Lg Q sub 0 and Lg coda Q sub 0 values in a sub-region northeast of the Lop Nor test site. For both explosions and earthquakes Lg Mo values correlate linearly with the ISC M sub b values, both having slopes slightly greater than 1.0. For the same Lg M sub 0 values, Mb values from explosions tend to be larger than those from earthquakes. Lg M sub 0 tend to scale with f (exp -alpha) sub c, with a closer to 4 than to 3. Regression analysis over M0 and f sub c values suggest that for the same M sub 0 values, explosions tend to have higher f sub c values. This may form a basis of an explosion discriminant, but the fact the there is a slight overlap among M sub 0 and f sub c values from explosions and those from earthquakes suggests that the use of this discriminant should be used with caution. Applications of the methodology used in this study to other regional phases, such as Pn, may contribute to our understanding of regional wave excitation/propagation by various types of seismic source, and to the evaluation of various discriminants using regional waves.

Download or read book U S National Report to International Union of Geodesy and Geophysics 1987 1990 written by and published by . This book was released on 1991 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monitoring the Comprehensive Nuclear Test Ban Treaty Seismic Event Discrimination and Identification written by William R. Walter and published by Springer. This book was released on 2013-04-18 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 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, and onsite inspections, to verify compliance. The problem of identifying small-magnitude banned nuclear tests and discriminating between such tests and the background of earthquakes and mining-related seismic events, is a challenging research problem. Because they emphasize CTBT verification research, the 12 papers in this special volume primarily addresses regional data recorded by a variety of arrays, broadband stations, and temporarily deployed stations. Nuclear explosions, earthquakes, mining-related explosions, mine collapses, single-charge and ripple-fired chemical explosions from Europe, Asia, North Africa, and North America are all studied. While the primary emphasis is on short-period, body-wave discriminants and associated source and path corrections, research that focuses on long-period data recorded at regional and teleseismic distances is also presented Hence, these papers demonstrate how event identification research in support of CTBT monitoring has expanded in recent years to include a wide variety of event types, data types, geographic regions and statistical techniques.

Download or read book Abstract Journal in Earthquake Engineering written by and published by . This book was released on 1993 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Geophysics written by Haruo Sato and published by Academic Press. This book was released on 2009-02-26 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic waves generated by earthquakes have been interpreted to provide us information about the Earth’s structure across a variety of scales. For short periods of less than 1 second, the envelope of seismograms changes significantly with increased travel distance and coda waves are excited by scattering due to randomly distributed heterogeneities in the Earth. Deterministic structures such as horizontally uniform velocity layer models in traditional seismology cannot explain these phenomena. This book focuses on the Earth heterogeneity and scattering effects on seismic waves. Topics covered are recent developments in wave theory and observation including: coda wave analysis for mapping medium heterogeneity and monitoring temporal variation of physical properties, radiation of short-period seismic waves from an earthquake fault, weak localization of seismic waves, attenuation of seismic waves in randomly porous media, synthesis of seismic wave envelopes in short periods, and laboratory investigations of ultrasonic wave propagation in rock samples. Understanding new methods for the analysis of short-period seismic waves to characterize the random heterogeneity of the Earth on many scales Observations of seismic wave scattering Discussion of techniques for mapping medium heterogeneity and for monitoring temporal change in medium characteristics Up-to-date techniques for the synthesis of wave envelopes in random media

Download or read book Seismological Research Letters written by and published by . This book was released on 1998 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monitoring the Comprehensive Nuclear Test Ban Treaty Seismic Event Discrimination and Identification written by William Walter and published by Springer Science & Business Media. This book was released on 2002-03-01 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 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, and onsite inspections, to verify compliance. The problem of identifying small-magnitude banned nuclear tests and discriminating between such tests and the background of earthquakes and mining-related seismic events, is a challenging research problem. Because they emphasize CTBT verification research, the 12 papers in this special volume primarily addresses regional data recorded by a variety of arrays, broadband stations, and temporarily deployed stations. Nuclear explosions, earthquakes, mining-related explosions, mine collapses, single-charge and ripple-fired chemical explosions from Europe, Asia, North Africa, and North America are all studied. While the primary emphasis is on short-period, body-wave discriminants and associated source and path corrections, research that focuses on long-period data recorded at regional and teleseismic distances is also presented Hence, these papers demonstrate how event identification research in support of CTBT monitoring has expanded in recent years to include a wide variety of event types, data types, geographic regions and statistical techniques.

Download or read book U S National Report 1987 1990 written by and published by . This book was released on 1991 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Earthquake Notes written by Seismological Society of America. Eastern Section and published by . This book was released on 1984 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: No. 1/2 of each vol., 1930- form the Proceedings or abstracts of proceedings of the section's annual meetings, some of which were held jointly with the Section of Seismology of the American Geophysical Union. No. for 1953-62 include Minutes of the Eastern Section meetings 25th-34th.