ON THE EARTHQUAKE AND VOLCANIC PHENOMENA OF JAPAN. llo 



a line traced through these, as shown on a key map, is an outline of the 

 hind area which was disturbed. The object of this catalogue, which is 

 different from previous publications of the same description, was stated in 

 the last report. 



Investigation of the Earthquake and Volcanic Phenomena of Japan. — 

 Fifteenth li.eport of the Comviittee, consisting of the Right Hon. 

 Lord Kelvin, Professor W. G. Adams, Mr. J. T. Bottomley, 

 Professor A. H. Gkeen, Professor C. G. Knott, ctncl Professor John 

 Milne (Secretanj). (Drawn up hy the Secretary.) 



Contents. 



PAGE 



I. T?io Grai/-Mil/ie Seism o/jrajjJi . . .113 



IL Ohiii-rrations n-ith Horizontal Pendulmns ,. . . . . .115 



(a) The Listrumeiits, Installation, Character of Movements . . .115 



(i) Dail;/ Ware Records 122 



(^) Tremors, Microseismic Bistiirhances, or Earth Pulsations . . .12^ 



(d) The Slow Displacement of Pendulums . ...... 128 



(e) Periodic morements of several days' diiration, and n-anderiiifj of 129 



the pendulums, 



(^f) The dailij change in the position of the pendulums . . . , ]f!0 



C.//) The Biiirnal Wave 131 



(h) Tremors 139 



(iS Meteor oloflieal Tallies for ToMo 143 



(7) Earthquakes recorded h>j Horizontal Pendulums in Tohio . . . 147 



III. Description of a Catalogue of 8,331 Earthquakes recorded in Japan 149 



hetn-een January 1885 and Decemher 1892. 



(rt) History of the Catalogues 149 



(J) E-f.planation of the Catalogues 151 



(c) Ohjeet of the Catalogues 153 



(Ji) Besults already obtained or shon-n hy the Catalogue and Map of 155 



Centres. 



IV. On the Velocities rvith which Waves and Vibrations are 2^'>'opagated on 158 

 the Surface of and through Poch and Earth. {Compilation^. 



Introduction . . . . . . . . . . . . ] 53 



(a) Observations on Artificially Produced Disturbances. Experiments 159 



of Mallet, Abbot, Fouque and Levy, Gray and Milne. 

 (i) Observations on Earthquakes. Where the nave j^aths have been 163 



short: (Milne and Omoei). WJiere the n-ave paths have been 



long : (Newcomb and DuTTON, Agamennone, Eicco, Cancani, 



VON Rebkue-Paschwitz. Milne). 

 (<■) The Probable Nature and Vdocity of Propagation of Earthquake 170 



Motion. The suggestions of Dr. C. G. Knott, Loed Rayleiuh, 



Loed Kelvin. 

 (d) The Paths I'oUo)ved by Earthquake Motion. Hypotheses of KoPKi^s 173 



and Seebach, Scujiidt, and a suggcstio>i by the writer, 

 {e) Conclusions 178 



V. Miscellaneous Notes relating to Large Earthquakes, i^x 179 



Appendix. — On Causes producing Movements which may be Mistaken for 182 

 Earth Tremors. 



I. The Gray-Milne Seismograph. 



The first of the above seismographs, constructed in 1883, partly at the 

 expense of the British Association, still continues to be used as the 

 standard instrument at the Central Observatory in Tokio. 



I am indebted to Mr. K. Kobayashi, the Director of the Observatoiy 

 for the following table of its records : — 



1895. . I 



I 



