j 76 A. Imamura. 



restoration of the ground to the original level was perceptible in some 

 ])laccs during a few days soon after tlie great earthquake. 



3. The survey of the base lines in Sagami Province, The net- 

 work of these base lines is indicated in Map II by a c|nadrilateral and 

 its diagonals, the former occupying an area to the west of Yokohama. 

 One of the diagonals, which joins Simomizo to Zama and is nearly 5210 

 metres long, was found to have increased its lengtli as much as 245 

 mm., while its north and south ends rose as much as 283 and 4,30 mm. 

 respectively. This result also agrees with the general phenomena relat- 

 ing to the topographical changes due to the great earthquake. 



4. Observations at trigonometrical points of the first class- 



Thirty-seven stations lying in the most disturbed area (PI. XL VI) were 

 examined ; but no definite results have 5^et been obtained. 



5. Observations at trigonometrical points of the second and 

 third classes. This work was begun in 1925 and is still in i)rogress. 

 The areas in Avhich the survey has already been finished or is to be 

 done this jenr, are shown in PI. XLVI. For the position of the stations 

 and the results of the observations, the readers are referred to Map. II. 



In that map, the position of each station is indicated by a 

 dot, and the vertical component of topographical change at that point 

 by figures attached to it. The latter was in each case estimated from 

 the results of triangulation at the different stations, taking the results 

 of the bench-mark survey as the standard. It will be seen that the 

 present observations give us some definite knowledge as to the areal 

 distribution of the topogra])hical changes on land, which the foregoing 

 ones did not give. Among the characteristic changes thus found to 

 have taken place, there are two noteworthy ones ; first, a belt of eleva- 

 tion traversing the southern part of the Boso peninsula in the direction 

 ENE— SSW, and second, a depressed area covering the NW part of 

 Pagami Province. Perhaps we can now picture roughly the actual 

 change in that part of the earth's crust lying in the NE side of the 

 assumed dislocation line across Sagami Bay, namely, a wavy flexure 

 with the southeastern side convex and the northwestern side concave, 

 both areas being bounded by a nodal line passing through Hakone in 

 the southwest and Atugi in the northeast. 



