Abstract
VARIATIONS in the ratio of compressional wave velocities and shear wave velocities, presage some earthquakes1. The ratio first decreases, but just before the earthquake it returns to, or rises above, the original value. An attractive model has been proposed by Nur2. Briefly, he suggested that anelastic expansion of the rock (dilatancy) reduced the velocities. With the subsequent rise of the pore pressure of water, the velocity increases again. The increased pore pressure also weakens the rock, resulting in an earthquake. All that effects the velocity of compressional waves more than the velocity of shear waves, giving the apparent variation in their ratio.
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References
Semenov, A. M., Bull. Acad. Sci. USSR, Phys. solid Earth, 3, 245 (1969); Nersesov, I. A., Semenov, A. N., and Simbireva, I. G., in Eksperimental' naia Seismologiia (edit. by Sadovskii, M. A.), 1 (Nauka, Moscow, 1971); Aggarwal, Y. P., Sykes, L. R., Armbruster, J., and Sbar, M. L., Nature, 241, 101 (1973); Whitcomb, J. H., Garmany, J. D., and Anderson, D. L., Science, 130, 632 (1973).
Nur, A., Bull. seism. Soc. Am., 62, 1217 (1972).
Aggarwal, Y. P., Simpson, D. W., and Sykes, L. R., EOS Trans. Am. geophys. Un., 55, 355 (1974).
McEvilly, T., and Johnson, L., Science, 132, 588 (1973); Bull. Seism. Soc. Am., 64, 343 (1974).
Robinson, R., Wesson, R. L., and Ellsworth, W. L., Science, 184, 1281 (1974).
Nur, A., Bell, M. L., and Talwani, P., Proc. Conf. Tectonic Problems of the San Andreas Fault System (edit. by Kovach, R. L., and Nur, A.), (Stanford University Publications, Stanford, 1973).
Gupta, I. N., J. geophys. Res., 78, 6936 (1973).
Anderson, D. L., Minster, B., and Cole, D., J. geophys. Res. (in the press).
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WANG, CY. Earthquake prediction and oriented microcracks in rocks. Nature 251, 405–406 (1974). https://doi.org/10.1038/251405a0
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DOI: https://doi.org/10.1038/251405a0
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