Correspondence — Professor Presticich, D.C.L. 191 



THE GREAT JAPANESE EARTHQUAKE. 



Sir, — In answer to some enquiries concerning the effects of the 

 great earthquake of 1891, Professor Koto, of Toky5, has just 

 favoured me with further interesting particulars that meet some 

 of the points mooted by the Rev. E. Hill, in this Month's Number 

 of the Magazine, and adds something to the Professor's previous 

 paper in the Japanese Journal of Science. In this letter he remarks : 

 " As to the qiiestions you put on my earthquake paper, I shall 

 attempt to answer you in a few particulars, though I may not satisfy 

 you, owing to my superficial geological knowledge. The uplift 

 in vertical direction, at its maximum point, is from 5\ to 6 metres. 

 This is, however, an exceptional one, found in Modori, in the Neo 

 Valley. This local uplift seems to me to have been caused by the 

 pushing up of the crust between two fault-lines by lateral pressure 

 of the neighbouring strata (see p. 340 of my paper). In all other 

 cases the vertical displacement is insignificant; in plains it may only 

 be seen by slight undulation of the ground. Along hill-sides it may 

 be seen in small landslips covered by soil, and in this case the fault 

 could not be distinguished from ordinary landslips accompanying 

 severe shocks. A very characteristic feature of the fault in question 

 is the horizontal displacement along the faulting plane, by which the 

 boundaries of field becomes discontinuous. From this displacement 

 I could measure the amount of shift of wing relative to the opposite 

 wing. Along the junction the soil is much disturbed and raised from 

 the surrounding field, appearing just like tracks of a mole. At the 

 spur of the hills this could not be well seen, as the junction is covered 

 by fallen talus. The displacement is, therefore, best studied in culti- 

 vated fields. I have traced the Neo fault for 112 km. by the marks 

 left in the fields by slight elevations, and by displacement of field 

 boundaries, and the regularity and constancy of these marks. Some- 

 times I have traced it in wooded hills where I often lost sight of the 

 marks, but by the help of the compass I caught the track again 

 beyond the hills on the other side. It was a very troublesome task 

 to keep my route right in this way. 



" You ask me whether the faulting plane is vertical or oblique ? I 

 am sorry I cannot tell you which it is. As may be understood 

 from the foregoing statement the vertical displacement, as a general 

 rule, amounts to very little. The best opportunity for study in this 

 direction may be that of Midori (photograph, PI. xxxiv.), but, 

 unfortunately, the faulting took place in alluvial ground, con- 

 sequently solid strata did not come into view at the surface. As 

 the raised mound in the fields is very narrow and sharply marked, 

 I surmise that the faulting plane is vertical, or nearly so ; if, on the 

 contrary, the faulting plane makes large angles, with normal upon 

 the surface, the head of shifting plane should not be so clearly 

 marked as in the Mino-Owari district, but the proximity of fault 

 must be much disturbed, which is not the case with ours. 



" Whether the hard rocks, as well as the drift-gravel and sand, 

 are affected by the fault is the next question you put to me, which 

 1 answer in the affirmative. As the line of fault goes through field 



