Abstract
FEW readers, and even few authors, of papers on periodicities in the occurrence of earthquakes have taken the trouble to compare the amplitudes they obtain with those that would be expected to arise from the harmonic analysis of a purely random set of observations. Piof. Conrad has done a great service in collecting the results and testing them in all cases by means of the Schuster criterion. Most of the suggested periodicities turn out to be probably not significant, on the ground that they would be just as striking if the observations were arranged in any other order in time instead of the actual one; Turner's 21-minute period is among these. The possible survivors are the diurnal and annual periods, and perhaps a 14-monthly one. The curious thing about the first two is that they are conspicuous in felt shocks, but not in instrumental ones. This suggests that they may be the result of differences between the conditions of observing by day and by night; but then why should the phase vary conspicuously from place to place? Why should it be opposite in some parts of Japan from others?
Handbuch der Geophysik.
Herausgegeben von Prof. Dr. B. Gutenberg. Band 2, Lief. 3: Die Erdoberfläche, von Erwin Kossinna; Petrographischer Aufbau der Erdkruste, von Dr. S. Rösch; Chemie der Meteoriten, von Prof. G. von Hevesy. Pp. 8691-119 + xv. 42 gold marks. Band 4, Lief. 4: Die zeitlichen Folge der Erdbeben und bebenauslösende Ursachen. Von Prof. Dr. V. Conrad. Pp. 10071202+xii. 39 gold marks. Band 7, Lief. 1: Das Eis der Erde, von Prof. Dr. H. Hess; Seen, von Prof. Dr. W. Halbfass; Das unterirdische Wasser, von Prof. Dr. W. Koehne. Pp. v+252. 42 gold marks. (Berlin: Gebrüder Borntraeger, 1932.)
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J., H. Handbuch der Geophysik. Nature 133, 84 (1934). https://doi.org/10.1038/133084a0
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DOI: https://doi.org/10.1038/133084a0