1887
Volume 5 Number 3
  • E-ISSN: 1365-2478

Abstract

A

Amplitude measurements have been made of the height of the first peak of an arrival refracted from a shallow refractor. If the amplitude is assumed to decay as the inverse mth power of the distance, the least squares value for is found to be 2.16 ± .04. Because of this value and because of the character of the recorded event it is concluded that the arrival is a simple critical refraction. After applying the theoretical ‘spread’ factor for critical refraction there remains a residual attenuation of 1.96 ± 0.28 decibels per 1000 feet. The predominant frequency in the pulse is about 20 c.p.s. and this attenuation agrees with the losses found for such a frequency by extrapolation of the published results of other workers. Although no evidence could be seen on the records for a change of pulse frequency with distance, the quoted result would be consistent with a dependence of residual attenuation on the first power of the frequency, and would be inconsistent with a dependence on the second power of the frequency.

It is concluded that studies of the amplitudes of refracted events will give useful estimates of the attenuation factors of rocks.

Loading

Article metrics loading...

/content/journals/10.1111/j.1365-2478.1957.tb01435.x
2006-04-27
2020-08-06
Loading full text...

Full text loading...

References

  1. Birch, F. & Bancroft, D., 1938, Elasticity and Internal Friction in a Long Column of Granite, Bull. Seism. Soc. Am., 28, pp. 243–254.
    [Google Scholar]
  2. Born, W. T., 1941, The Attenuation Constant of Earth Materials, Geophysics, 1, pp. 6–132.
    [Google Scholar]
  3. Bruckshaw, J. & Mahanta, P., 1954, The Variation of the Elastic Constants of Rocks with Frequency, Petroleum, 17, pp. 14–18.
    [Google Scholar]
  4. Cagniard, L., 1939, Reflexion et Refraction des Ondes Seismiques Progressives, Gauthier‐Villars, Paris .
    [Google Scholar]
  5. Collins, F. & Lee, C, 1956, Seismic Wave Attenuation Characteristics from Pulse Experiments, Geophysica, 21, pp. 16–40.
    [Google Scholar]
  6. Ewing, M. & Press, F., 1954, An Investigation of Mantle Rayleigh Waves, Bull. Seism. Soc. Am., 44, pp. 127–149.
    [Google Scholar]
  7. Heelan, P. A., 1953, On the Theory of Head Waves, Geophysics, 1, pp. 18–871.
    [Google Scholar]
  8. Kendall, J. M., 1941, The Range of Amplitudes in Seismic Reflection Records, Geophysics, 1, pp. 6–149.
    [Google Scholar]
  9. Knopoff, L., 1956, The Attenuation of Compression Waves in Lossy Media, Bull. Seism. Soc, Am., 46, pp. 47–56.
    [Google Scholar]
  10. O'Brien, P., 1955, Model Seismology; the Critical Refraction of Elastic Waves, Geophysics, 20, 227–242.
    [Google Scholar]
  11. Officer, C, Jr., 1953, The Refraction Arrival in Water Covered Areas, Geophysics, 4, pp. 18–805.
    [Google Scholar]
  12. Pekeris, C., 1948, Theory of Propagation of Explosive Sound in Shallow Water, Geol. Soc. Am., Memoir 27.
    [Google Scholar]
  13. Pickett, G., 1955, Seismic Wave Propagation and Pressure Measurements near Explosions, Quarterly of the Colorado School of Mines, Vol. 50, No. 4.
    [Google Scholar]
  14. Ricker, N., 1949, Attenuation and Amplitudes of Seismic Waves, Trans. A.G.U., 30, pp. 184–186.
    [Google Scholar]
  15. A list of Ricker's earlier publications on seismic amplitudes is given in this paper.
  16. Sokoloff, P. & Skriabin, V., 1937, Experimental and Theoretical Investigations on Dispersion and Absorption of Elastic Waves. Gerlands B. zur Geophysik, 49, 165–198.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/j.1365-2478.1957.tb01435.x
Loading
  • Article Type: Research Article
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error