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The Distribution of Deep-focus Earthquakes

Published online by Cambridge University Press:  01 May 2009

Charles Davison
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Extract

During the years 1918–1931, there were 270 earthquakes with unusually deep foci, 167 in the Northern Hemisphere, 101 in the Southern, and two with epicentres on the equator. The normal depth of focus is assumed to be about 50 km. or ·008 of the earth's radius. The focal depths of the above earthquakes range from ·005 to ·090 of the earth's radius below the normal depth, or from 50 to 380 miles beneath the surface. Throughout this paper, the depth, when given in terms of the earth's radius, is referred to the normal depth; when given in miles, to the surface of the earth.

Type
Original Articles
Information
Geological Magazine , Volume 74 , Issue 7 , July 1937 , pp. 316 - 324
Copyright
Copyright © Cambridge University Press 1937

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References

1 Intern. Seis. Sum., 1918–1931;Google Scholar Turner, H. H., “Catalogue of Earthquakes 1918–1924” (Brit. Ass. Rep., 1928, pp. 241–304)Google Scholar; and Miss Bellamy, E. F., “Catalogue of Earthquakes, 1925–1930” (Brit. Ass. Rep., 1935, pp. 230–304);Google Scholar and Index catalogue of epicentres for 1913–1930 (County Press Office, Newport, I.W.).Google Scholar