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  • 1
    Electronic Resource
    Electronic Resource
    MEASUREMENTS OF EARTH ATTENUATION FROM DOWNHOLE AND SURFACE SEISMIC RECORDINGS (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 32 (1984), S. 0 
    Details
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Frequency-dependent attenuation of compressional waves within the earth has been estimated in the vicinity of wells from〈list xml:id="l1" style="custom"〉1spectral power ratios of the coherent events in separate time gates on the seismic section2matching a broadband synthetic trace with seismic data at the well, and3determining the operator that transforms one down(up) going pulse recorded in the well into another recorded at a deeper (shallower) level.The accuracy of estimation of all three methods was insufficient to estimate attenuation over small depth intervals, and it was not possible to distinguish between the contribution due to internal multiples and that of genuine absorption with much confidence. Spectral ratios from (1) showed a smoother variation with frequency—and one more consistent with other estimates—when they were compensated for the spectra of the reflectivities over the time gates employed, but they did not provide more than a broad indication of attenuation over a substantial depth interval. Approach (2) was hampered by the restricted durations over which synthetic trace and seismic data can be reliably matched; approach (3) gave the best results. Here matching is a much more powerful tool than the spectral-ratio techniques that are commonly applied since it can yield the form of the attenuation operator, i.e., both its amplitude and phase response, together with properly defined measures of its accuracy, while at the same time it minimizes the influence of noise and local interference effects at each recording level.For seismic target depths where internal multiple activity was low the logarithms of the amplitude responses of the estimated attenuation operators decreased approximately linearly with frequency and the phase responses showed no significant dispersion. Application of approach (3) to downgoing and upgoing waves estimated from a vertical seismic profile revealed the importance of changes in frequency-dependent geophone coupling and their effect on values of Q determined from downgoing pulses only.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2478.1984.tb00745.x
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    Paper (German National Licenses)
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  • 2
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    MEASUREMENTS OF EARTH ATTENUATION FROM DOWNHOLE AND SURFACE SEISMIC RECORDINGS* (1984)
    Wiley
    Details
    Publication Date: 1984-10-01
    Print ISSN: 0016-8025
    Electronic ISSN: 1365-2478
    Topics: Geosciences , Physics
    Published by Wiley
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  • 3
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    Post-shock temperatures in minerals (1979)
    Oxford University Press
    Details
    Publication Date: 1979-09-01
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Royal Astronomical Society.
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  • 4
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    Post-shock temperatures in minerals (1979)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: An experimental technique for the measurement of post-shock temperatures in minerals is presented, and silicate post-shock temperature measurements are compared with theoretical calculations. The technique involves the use of infrared detectors to determine the brightness temperatures at 4.5 to 5.75 microns and 7 to 14 microns of samples shocked to between 5 and 30 GPa. Results obtained for aluminum 2024 and stainless steel 304, as well as for Bamble bronzite and synthetic crystal forsterite are found at low pressures to be considerably in excess of the temperatures predicted assuming a hydrodynamic rheology and isentropic release parallel to the Hugoniot. The results are shown to be in better agreement, however, with values calculated assuming elastoplastic behavior, and the post-shock temperatures of crystalline quartz are found to be in good agreement with those calculated by Mashimo et al. (1979) from release adiabat data.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Geophysical Journal; 58; 1979
    Format: text
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  • 5
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    Post-shock temperatures in minerals (1978)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Post-shock temperatures were measured in a wide variety of materials, including those of geophysical interest such as silicates by using an infrared detector to determine the brightness temperature of samples shocked to pressures in the range 5 to approximately 30 GPa. Measurements were made in the 4.5 to 5.75 micron and in the 7 to 14 micron wavelength ranges. Reproducible results, withe the temperatures in the two wavelength bands generally in excellent agreement, were obtained for aluminum-2024 (10.5 to 33 GPa; 125 to 260 C), stainless steel-304 (11.5 to 50 GPa; 80 to 350 C), crystalline quartz (5.0 to 21.5 GPa; 80 to 250 C) forsterite (7.5 to 28.0 GPa; approximately 30 to 160 C) and Bamble bronzite (6.0 to 26.0 GPa; approximately 30 to 225 C). Results are generally much higher at low pressures than the values calculated assuming a hydrodynamic rheology and isentropic release parallel to the Hugoniot but tend towards them at higher pressures.
    Keywords: SOLID-STATE PHYSICS
    Type: NASA-CR-157738
    Format: application/pdf
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  • 6
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    Regional variations in upper mantle compressional velocities beneath southern California 1. Post-shock temperatures: Their experimental determination, calculation, and implications, 2. (1978)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The compressional velocity within the upper mantle beneath Southern California is investigated through observations of the dependence of teleseismic P-delays at all stations of the array on the distance and azimuth to the event. The variation of residuals with azimuth was found to be as large as 1.3 sec at a single station; the delays were stable as a function of time, and no evidence was found for temporal velocity variations related to seismic activity in the area. These delays were used in the construction of models for the upper mantle P-velocity structure to depths of 150 km, both by ray tracing and inversion techniques. The models exhibit considerable lateral heterogeneity including a region of low velocity beneath the Imperial Valley, and regions of increased velocity beneath the Sierra Nevada and much of the Transverse Ranges. The development is described of a technique for the experimental determination of post-shock temperatures, and its application to several metals and silicates shocked to pressures in the range 5 to 30 GPa. The technique utilizes an infra-red radiation detector to determine the brightness temperature of the free surface of the sample after the shock wave has passed through it.
    Keywords: GEOPHYSICS
    Format: application/pdf
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  • 7
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    Post-shock temperatures in minerals (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental technique was developed for measuring post-shock temperatures in a wide variety of materials, including those of geophysical interest such as silicates. The technique uses an infrared radiation detector to determine the brightness temperature of samples shocked to pressures in the range 5 to approximately 30 GPa; in these experiments measurements were made in two wavelength ranges (4.5 to 5.75 microns and 7 to 14 microns). Reproducible results, with the temperatures in the two wavelength bands generally in excellent agreement, were obtained for aluminum-2024 (10.5 to 33 GPa, 125 to 260 C), stainless steel-304 (11.5 to 50 GPa, 80 to 350 C), crystalline quartz (5.0 to 21.5 GPa, 80 to 250 C), forsterite (7.5 to 28.0 GPa, approximately 30 to 160 C) and Bamble bronzite (6.0 to 26.0 GPa, approximately 30 to 225 C). It is concluded that release adiabat data should be used, wherever available, for calculations of residual temperature, and that adequate descriptions of the shock and release processes in minerals are more complex than generally assumed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-CR-158118 , CONTRIB-3143
    Format: application/pdf
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  • 8
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    Measurement of post-shock temperatures in aluminum and stainless steel (1979)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Until recently experimental measurements of post-impact temperatures have been obtained only for metals at high pressures. Our aim has been to develop a technique for measuring post-shock temperatures in a variety of materials, including metals and silicates, at pressures in the range of 5 to 50 GPa, providing further insight into the shock process in these substances and additional constraints to available equation of state data. This paper describes the method we have developed, and its application to the determination of post-shock temperatures in aluminum-2024 and stainless steel-304.
    Keywords: METALLIC MATERIALS
    Type: High-pressure science and technology; Sixth International Conference; Jul 25, 1977 - Jul 29, 1977; Boulder, CO
    Format: text
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    NASA TECHNICAL REPORTS
  • 9
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    Regional variations in upper mantle structure beneath Southern California (1980)
    Oxford University Press
    Details
    Publication Date: 1980-10-01
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Royal Astronomical Society.
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