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SCIENCE PROGRESS 



area occupied by the northern part of Kagoshima Bay and the 

 surrounding land, where the depression of the ground was 

 more or less marked, an irregular circle about 28 miles in 

 diameter. It would seem, he adds, that the particular portion 

 of the lava reservoir which supplies magma to the active 

 volcanoes of Sakura-jima and Kirishima is situated, not under 

 the volcanoes themselves, but under the region between them. 

 The volume of the basin formed by this subsidence is of some 



-2m. 



Fig. 4. — Vertical crust-displacements in Sakura-jima. 



interest. Prof. Omori estimates the volume of depression 

 within the 300 mm. curve as one-fifth of a cubic mile, and of 

 that within the 100 mm. curve as one-eighth of a cubic mile, the 

 total being in any case not less than one-half the combined 

 volumes of lava and ashes ejected. 



Within Sakura-jima itself, the triangulation surveys of 

 1898 and 1 9 14 reveal results of no less importance, as regards 

 both vertical and horizontal movements. The former are 

 represented graphically in fig. 4. In the coast districts, the 



