著者

和達 清夫

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.10, no.9, pp.540-551, 1932

被引用文献数

1

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The velocity ratio of P and S waves is obtained by many authors to be nearly constant everywhere in the earth's crust. In the present investigatio_??_, is treated this problem by a method of <i>t_p-T_p-s</i> diagram which gives the relation between the arrival time of P and duration of (P-S). Examining in many cases of large earthquakes of both shallow and deep origins occurred in our country, the relation is obtained to be approximately linear as is expected, especially in the cases of deep-seated earthquakes. From these investigations, the velocity ratio of P and S waves is obtained as about 1.73 in the upper part, it may be probably the so-called Mohorovicic layer, but its value seems to differ in different localities; while, in the deeper part nearly a constant value of 1.79 is obtained. Thus, using the result we are able to obtain the depth of seismic focus by a simple method, especially in case of deep-seated earthquakes.