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Science 20 September 1974:
Vol. 185. no. 4156, pp. 1047 - 1049
DOI: 10.1126/science.185.4156.1047
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Articles

Earthquake Prediction: Absence of a Precursive Change in Seismic Velocities before a Tremor of Magnitude 3frac34

A. McGarr 1

1 Bernard Price Institute of Geophysical Research, University of the Witwatersrand, Johannesburg, South Africa

P-wave velocities in the region near the source of a tremor of magnitude 3frac34 were constant to within 2 percent for 41 days before the event; no evidence of a precursive change in velocity was found. Observations of S-wave velocities and the ratio of P-wave to S-wave velocities also showed no precursive changes. In recent studies, premonitory changes in body-wave velocities of about 10 percent and having a duration of 2 to 3 weeks have been reported for crustal earthquakes of this size.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Precursors to a magnitude 4.8 earthquake in the Virgin Islands: Spatial clustering of small earthquakes, anomalous focal mechanisms, and earthquake doublets.
A. FRANKEL (1982)
Bulletin of the Seismological Society of America 72, 1277-1294
   Abstract »    PDF »
Strong ground motion of mine tremors: Some implications for near-source ground motion parameters.
A. MCGARR, R. W. E. GREEN, and S. M. SPOTTISWOODE (1981)
Bulletin of the Seismological Society of America 71, 295-319
   Abstract »    PDF »
Relationship of mine tremors to induced stresses and to rock properties in the focal region.
A. MCGARR, S. M. SPOTTISWOODE, and N. C. GAY (1975)
Bulletin of the Seismological Society of America 65, 981-993
   Abstract »    PDF »


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