The Times of P up to 30� (Second Paper)

Summary A new set of earthquakes is studied to check the times of P in European earthquakes up to 30°, and especially the behaviour near 20°. The corrections to the author's table of 1939 agree closely with those found from an earlier set in 1935. Lehmann's observations of Pd are consistent with her interpretation if Pr overtakes Pd at about 14°, but in any case dt/dΔ for Pd is remarkably constant. It seems probable that there is triplication and that the observations refer to a neighbourhood of the more distant cusp on the time curve. No useful new data were available for the Japanese region. Several earthquakes in North and Central America showed that from 8° to 30° the 1939 table is correct to a fraction of a second apart from a possible additive constant. Additional information on the times at distances under 8° was given by a paper of Lehmann. The data in this indicate that the European velocity is nearly correct for North America, but that, relative to 5°, the times from 8° to 30° for American earthquakes are about 2 s shorter than for European ones.