ON SEISMOLOGICAL INVESTIGATIONS. 



43 



Table VI. — continued, 

 1914 March W 6^ 17™ 86' : 54° N. 156° E. {Pulkovo). 



In these two cases it looks as though the time-determinatioa at 

 Zi-ka-wei were faulty. [Fuller particulars are given in the Shide 

 Bulletin for March.] Let us omit Zi-ka-wei from consideration for 

 the moment. The 0-C in the fifth column is that given in the Shide 

 Bulletins. The suggested corrections in the next column are from 

 the above table. Wlien these are appUed, it is seen that the stations 

 near the origin agree better among themselves, but still differ systemati- 

 cally from those further away, especially Pulkovo; but at the same 

 time it may be seen that the azimuth of the nearer stations is quite 

 different. We can displace the epicentres at right angles to the 

 direction of Pulkovo without disturbing its A or error. The effect 

 of thus moving the epicentre 2O'0 in the first case and 4°'0 in the 

 second is shown in the column ' epicentre correction. ' It will be seen 

 that all are brought into fair accord, with the above-noted exception 

 of Zi-ka-wei; further, that the suggested corrections to the tables are 

 in the case of Zi-ka-wei - 15' and + 17^ in opposite directions in the 

 two earthquakes, and both tending to assimilate the en'ors for this 

 station to an error in time-determination. 



In the following example the suggested correction has the appear- 

 ance of being in the right direction, but excessive in amount. Osaka 

 and Batavia especially, which differed by -1-8^ before correction, now 

 differ by — 23'. This mny be due to error in epicentre ; if again we accept 

 Pulkovo as correct in distance, but wrong in azimuth, and accordingly 

 move the epicentre 1°'2 in the direction at right angles to Pulkovo, 

 we get the ' epicentre corrections ' shown in the 8th column. 



Table VII. 

 1914 July 6^ &^ QT^ 24* : 24°-0 N. 121°-5 E. {Shide Determination). 



