24 C. Davison — Great Japanese Earthquake, 1891. 



I have made use of Professor Milne's great catalogues of Japanese 

 earthquakes during the eight years 1885-92.^ 



In the first ^ of the accompanying maps, the district in which the 

 Mino-Owari earthquake and its after-shocks originated, is enclosed 

 between the undulating dotted lines. The neighbouring regions 

 whose seismic activity is to be investigated, are bounded by straight 

 dotted lines, and denoted by the letters A, B, C, D, E, F. The 



curves represent the distributioa of epicentres within and near these 

 areas. In constructing these curves, the map is divided into rect- 

 angles whose sides are respectively one-sixth of a degree of latitude 

 and longitude in length, so that sixteen of these rectangles adjoin 

 the north-south side of the map, and twenty-one adjoin the east- west 

 side, the whole map containing, therefore, 336 rectangles. The number 

 of epicentres lying within each rectangle during the eight years 

 mentioned being counted, curves are drawn through the centres of 

 the rectangles in which five and ten epicentres respectively are found ; 

 or, when the numbers are not exactly five or ten, through points 

 which divide the lines joining the centres of adjacent rectangles in 



1 Seismol. Journ. of Japan, vol. iv, 1895. 



2 This map is bounded by the parallels 34° 40' and 37° 20' of north latitude, and 

 by the meridians 1° 0' and 4° 30' west of Tokio. 



