280 T. Terada and T. jNIatuzawa 



The mechanism of occmTence is inferred, as a natural course, to be 

 akin to that assumed by T. Terada and stated below, though the 

 nature of the impulses is considered to be somewhat different. 



Nagaoka's theory of the nature of the phenomena of pulsation 

 will be referred to later. 



T. Terada and U. Nakaya'^^^ recently made an experiment on the 

 motion of a pendulum subjected to a rapid irregular succession of 

 impulses by the impinging stream of birdshot. The records of the 

 motion of the pendulum show an appearance very similar to the 

 seismograms of pulsations. Thence, Terada is inclined to suppose a 

 mechanism for the production of pulsations in which a discrete geo- 

 logical unit or block might play the role of the pendulum in the 

 above experiment upon which numerous irregular swarms of impacts 

 due to meteorological, oceanic, as well as terrestrial,, causes of distur- 

 bances, are acting as an assemblage of impulses.'^^^ 



Phenomena Accompanying Earthquakes. 



Among the phenomena accompanying earthquakes, one having 

 the most important significance is the deformation of the earth crust 

 as revealed by the formation of apparent fault lines, or by the 

 sensible upheaval or depression of the surface. The fault lines have 

 been traced and discussed by many geologists and seismologists on the 

 occasions of different destructive earthquakes. Among others, those in 

 the earthquakes of Mino-Owari,^"'^ Akita/'*' Anegawa,^^^ Oomati^^^ and 

 Simabara''^ may be especially mentioned. Remarkable fault lines have 

 been identified also in the cases of strono; Formosan earthquakes.'®^ 



(1) To be published shortly iu Scientific Papers of the Institute of Physical and 

 Chemical Research, T6kyo. 



(2) T.S.B.K., 9 (1917), 142. 



(3) Omori, Ho., 2 (1894) ; 32 (1900) ; Bull., 1, No. 2 (1907); T.S.B.K., 4 (1907), 30. 



(4) B. Koto, Ho., 8 (1896). Yamasaki, Ho., 11 (1897). Also Imamura, Ho., 77 

 (1913j. K. Aomi, Ho., 82 (1915). 



(5) B. Koto, Ho., 69 (1910). 



(6) S. Tuboi, 98(1922). Omori, Ho., 94 (1921); 98(1922); Bull., 10, No. 1 (1922). 

 Saem. Nakamura, J.M.S., 37 (1918), 390 ; 38 (1919), 41, 147. 



(7) Imamura, Ho., 99(1925). S. Nakamura, J.M.S., 42 (1923), 1. K. Suda, U.t.S., 

 3 (1923), 2, 14. T. Ogawa, Mem. Kyo., B. 1, No. 2, Art. 2 (1924). 



(8) Omori, Bull., 1, No. 2 (1907). 



