On the Travel Time of the P₁' Wave Observed near the Antipodes

Abstract

It is well-known that the focal depth of an earthquake can be precisely estimated by the travel time of earthquake waves observed near the antipodes, if the time of occurrence at the focus be known. For this object, we attempted to get a table of accurate travel times of the P₁' wave near the antipodes (>145°) from the observational data of the New Zealand earthquake (1929, VI 16) which was precisely investigated by Miss Lehmann (Gerl. Beit. z. Geo. Bd. 26, S. 402.) The result obtained is shown in Table III, which can be used for normal as well as deep-focus earthquakes. The values in this table are in a good coincidence with the results obtained by the observation of the deep-focus earthquake (1931, II 20) occurred in the North Japan Sea.