Abstract
IN the Philosophical Transactions of the Royal Society, Series A, vol. 222, pp. 45–56 (1921), Mr. G. W. Walker, relying on certain observations of the emergence-angle of P waves at Pulkovo, makes the somewhat startling suggestion that the depth of focus is of the order one-fifth of the earth's radius, or about 1250 km. This is a much larger estimate of depth than that hitherto suggested, viz. of order less than 100 km. Mr. Walker's estimate of depth is a consequence of accepting the Pulkovo numbers as correct. It appears that the values of the apparent angle of emergence calculated from Zöppritz's curve do not agree with its value directly measured at Pulkovo. This discrepancy is so marked that either the time-curve or the Pulkovo values must be seriously in error, and Mr. Walker proceeds on the assumption that within the limits of possible error in the time-curve we can modify it so as to agree with the direct measure of the apparent angle of emergence.
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BANERJI, S. The Depth of Earthquake Focus. Nature 109, 108 (1922). https://doi.org/10.1038/109108c0
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DOI: https://doi.org/10.1038/109108c0
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