ON THE EARTHQUAKE AND VOLCANIC PHENOMENA OF JAPAN. 115 



that might be written about at interminable length, and therefore in this 

 short Report no attempt is made to give detailed descriptions of all that 

 happened. 



Mr. F. Omori, who works with me in the Seismological Laboratory, 

 has spent several weeks in the shaken district, and ever since has been 

 busily engaged in analysing the materials he collected. Professor 

 Tanakadate, with a staff of assistants, devoted himself to observations 

 relating to the velocity of propagation of earth- waves, the curious sound 

 phenomena, and, lastly, to a redetermination of magnetic elements in the 

 devastated district. Dr. B. Koto has studied the phenomena from a 

 geological standpoint. 



Under the title of ' The Great Earthquake in Japan,' in conjunction 

 with Professor W. K. Burton, I have published a general account of the 

 more striking phenomena which were observed, illustrating the same by 

 a series of photographs. The questions to which greatest attention has 

 been given are those of importance to engineers and builders, but 

 inquiries and investigations have been made relating to everything 

 which was thought to be of interest. A few days after the disaster, at 

 the request of Professor D. Kikuchi, I drew up a circular containing 

 some fifty queries. Ten thousand of these documents were issued, and 

 now, here and at the Central Observatory, we are surrounded by boxes 

 filled with newsjDaper cuttings and replies. Five per cent, of the whole 

 may be of value, but yet it has all to be patiently examined. In addition 

 to this material, there is that of our own collecting, which, in addition to 

 what has already been mentioned, includes some hundreds of diagrams 

 taken by seismographs of what seemed to be at one time an unending- 

 series of shocks which followed the great disaster. This chaotic mass of 

 material is gradually being sifted, and assuming a form suitable for 

 systematic investigation. Although many of the results may be marked 

 by the magnitude of the phenomena they represent rather than by 

 their novelty, we have already gone sufficiently far to see that certain 

 observations can hardly fail in widening the circle of our present 

 knowledge. 



The first notice that I received of the earthquake was at 6h. 39m. lis. 

 on the morning of October 28, whilst I was in bed. From the manner in 

 which the house was creaking and the pictures swinging and flapping on 

 the wall I knew the motion was large. My first thoughts were to see 

 the seismographs at work ; so I went to the earthquake-room, where to 

 steady myself I leaned against the side of the stone table, and for about 

 two minutes watched the movements of the instruments. It was clear 

 that the heavy masses suspended as horizontal pendulums were not 

 behaving as steady points, but that they were being tilted, first to the 

 right, and then to the left. Horizontal displacements of the ground were 

 not being recorded, but angles of tilting were being measured. That 

 whenever vertical motion is recorded there must be tilting, and therefore 

 no form of horizontal pendulum is likely to record horizontal motion, is 

 a view I have often expressed. What I then saw convinced me that 

 such views were correct. Next I ran to a water-tank which is 80 feet 

 long, 28 feet wide, and 25 feet deep. Its sides are practically vertical. 

 At the time it was holding about 17 feet of water, which was running 

 across its breadth, rising first on one side and then on the other to a 

 height of about 2 feet. It splashed to a height of 4 feet. It seemed 

 clear that the tank was being tilted, first on one side, and then on the 



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