282 F. OINOUYE 



which were broken and shattered. Many were blown out of the 

 ground by the explosion, while others were buried and broken by 

 the fall of bombs and ashes (Fig. 21). The bombs, however, were 

 not thrown more than 500 m. from the craters, but the sand and 

 ashes were driven to a distance of several kilometers. Often 

 heavy showers of sand and ashes were seen to fall in localized 

 areas, in many places forming long strips of debris on the land. 

 At one place in a field of barley the strip measured 3 m. wide and 

 was traced for a distance of 200 m. While in the air these masses 

 of ejectamenta looked like a jet of water issuing from a hose. 

 This effect was produced by air currents concentrating the material 

 into long lines. The damage done by falling ash, including injury 

 to farm land as well as destruction of houses, etc., was heavy 

 within a radius of 2 km. of the craters. The most severe damage 

 by ash and mud-flow amounted to 3 sq. km. of land covered. Five 

 houses were carried down to the lake by the mud-flow, and a few 

 houses were buried by the heavy ashes, while five other houses were 

 shattered as a result of the local undulation of the land. At Abuta, 

 a distance of 4 km. from the nearest crater toward the northwest, 

 a monument and a small house fell, together with three brick walls 

 (Figs. 1, 3, 4) and two plaster ones of a storehouse. In the same 

 village many cracks developed in the walls of the houses. 



V. CHANGE OP TOPOGRAPHY 



On July 28 the writer found the rise of the water of Lake Toya 

 on the north side to be about 30 cm. On August 6 Dr. Omori 

 found a lowering of the water-level on the south side of the lake. 

 From August 20 it was noticed that the north side of the second 

 group of craters began to rise. This elevation (155 m. high from 

 the lake-level, according to Professor F. Omori) continued till the 

 end of November. The slope of the southern shore of the lake was 

 about 5 degrees. It then gradually rose to a slope of 30 degrees at 

 the top of the elevation, and 22 degrees on its flank. A photograph 

 taken by the writer on September 4 shows a house which, originally 

 constructed upright, was then inclined 12 degrees from the vertical. 

 Two days later this house had collapsed (Fig. 22). Before the 



