THE GREAT ERUPTION OF SAKURA-JIMA IN 1914. 127 



In the Bonin islands an afterglow of tlie sun, as in the 

 Krakatoa eruption of 1883, was observed and dust began to rain 

 from 5.30 a.m. of the 13tli. It was transported thither with a 

 velocity of 30 m. per second. Some doubts were entertained as to 

 the source of the Bonin ashfall, as a new volcanic island rose on 

 January 23rd from sea-level near South Iwô-jima, which lies to 

 the south of the above-mentioned group. 



The wi'iter abstains from calculating the amount of éjecta from 

 the Sakura-jima vents, because of the want of data for trustworthy 

 estimation in sucli loose volcanic products of various dimensions.^^ 



A 



According to F. Omoei, the volume is 0.62 cub. km., which is 

 equivalent to 4:0% of that of new lava, and 1/25 of the volcano 

 of Sakura-jima above sea-level. The ratio of the volume of éjecta 

 to new solid lava is 8:5. In the Krakatoa eruption of 1883 

 (loc. cit., p. 122, footnote 2) the total volume of pumice and dust 

 was estimated at 9^% of the whole éjecta, there being no lava 

 flows at that time.'^ The fine pumice of that event was roughly 

 calculated to be 3.5 times and the coarser sort 5.5 times lighter 

 than the compact lava. 



Yii. The Subsidence of the Sakura-jima Environs. — After the cat- 

 astrophe of Sakura-jima on January 12th, 1914, it was rumored 

 that the neighborhood was gradually subsiding. Unequivocal signs 

 were at hand : the overflow of bay waters into paddy fields and 

 salt gardens over and through embankments on shore, thereby 

 endangering both the rice culture and industry. Houses at Futa- 

 mata and Shirahama standing on the northern shore of the volcano 

 island became exposed to spray upon their w^ndow^s, where they 



1) In Kiigoshima it was estimated that the dry ash occupying a sq. m. with a thickness 

 of 2 mm. weighed 118 grammes. 



2) In the CotopaxL eruption of 1880, the quantity of ash was estimated as 2,000,000 tons ; 

 that of Katmai occupied 5 cub. miles. 



