ON THE EARTHQUAKE AND VOLCANIC PHENOMENA OF JAPAN. 93 



hour 47 minutes. These waves liad a submarine origin about 40 miles off 

 the N.E. corner of Yezo, in about 43^ N. lat. and 140° E long., and to reach 

 Tokio had travelled some 570 miles. I think that they have been recorded 

 in Rome, and I have written to Dr. E. von Rebeur-Paschwitz to learn 

 whether they were noted at Potsdam, Wilhelmshaven, and Strassburg. 

 They ought to have reached the Birmingham iiastrurnent about midday on 

 March 22. 



While I am writing in Sapporo (Yezo), on June 20, at 2.-32 p.m., a 

 terrible earthquake has happened in Yokohama and Tokio. As we are 

 9 hours E. of Greenwich this should be recorded at the above stations? 

 and those in Russia at about 6.30 a.m. on the same day. 



From the manner a pendulum behaves I infer that its movements are- 

 due to the fact that it is being tilted, and because the photographic records 

 are always less than the distances through which I have seen it move, the- 

 values given for the tilting are less than those which actually happened. 

 If a pendulum is set swinging, for example, by standing near its column, 

 thi'ough a distance of, say, 5 mm., it will come to rest in about 5 minutes. 

 In calculating the duration of a disturbance allowance has been made for 

 this factor. 



The point of greatest importance in connection with the foregoing 

 remarks is the inference that the catalogue of Kamakura earthquakes 

 represents a series of large disturbances which have travelled very great 

 distances. Had there been any local disturbances sufficiently great to 

 produce earth waves, then the pendulums must have recorded the same, 

 but no such disturbances occurred. As it is not likely that earthquakes 

 originating at a distance could in any way be connected Avith local tilting, 

 if earthquakes and tilting have any connection those which might be 

 compared with the curves already given are those of local origin which 

 have been recorded by seismographs in the vicinity, and not those which 

 are shown on the photographic films. Between January 24 and March 18 

 lifteen shocks were noted in Tokio, which cannot be seen on the photo- 

 graphic traces. Because nearly all these were of the nature of elastic 

 vibrations it is probable that they were for the most part of local origin. 

 This is a point which can only be definitely settled by analysing the reports 

 accumulated at the Meteorological Bureau, which for various reasons 

 cannot be done in time for the present report. These 1 5 shocks are indicated 

 on the curves as black dots, and it is certainly woi'th observing that they 

 chiefly occur during the seventh, eighth, and ninth weeks when tilting was- 

 marked. Because the observations are few and because I am not yet in a 

 po-sition to analyse all the materials which have been accumulated, too great 

 stress should not be laid upon this last observation. It only indicates the 

 nature of an inquiry that is being made. 



The last point to which attention must be called in connection with 

 the Kamakura disturbances is that the greatest motion has nearly always 

 been in the direction of the dip, that apparently being the direction of 

 least resistance to yielding. By reference to the catalogue it will be seen 

 that there are three instances where small disturbances have only been 

 recorded by C, but in all other cases the records are given by both instru- 

 ments, the dip record being much the larger, or the record has been given 

 by D alone. For example on February 8 D was tilted for 30 minutes 

 through an angle of nearly 7", while C did not show that any motion 

 had taken place. 



