350 The Ohio Journal of Science [Vol. XX, No. 8, 



THE GOHNA LANDSLIDE. 



On September 6, 1893, an enormous mass of rock fell 4000 

 feet from Mount Maithana, in the Himalayas, into the Bhirai 

 Gunga, at its foot. The violence of the fall is attested by the 

 formation of great clouds of dust which darkened the neighbor- 

 hood for miles around and on falling covered the ground like 

 snow. The falls lasted for three days and continued in rainy 

 weather for many months. The fallen material formed a 

 great dam stretching along the river for two miles, filling the 

 channel to a depth of 900 feet; the length across the gorge was 

 600 feet in the bottom and 3000 feet at the top, the thickness of 

 the dam up and down stream was 11000 feet at the bottom and 

 2000 feet at the top. Above the dam a great lake, with a max- 

 imum depth of 777 feet, accumulated, and was later released in 

 one of the greatest floods of record. Although the surface 

 covered by the debris was only 423 acres, it is evident that the 

 amount of material far exceeds any of the slides discussed above. 



THE GREAT SLIDE AT BANDAI SAN. 



What appears to be the greatest landslide of which I have 

 been able to find a record is a phenomenon not previously 

 considered in connection with landslides at all, but as a peculiar 

 sort of volcanic explosion — the eruption of Bandai San, in 

 the province of Iwashiro, Japan, July 15, 1888, which covered 

 an area of some 27 square miles with its detritus. Although 

 this disturbance as described by Sekiya and Kikuchi* admittedly 

 involved no magmatic extrusion, there seems no good reason 

 to doubt the belief of the Japanese authors that it originated in 

 a series of steam explosions in rock affected by some subter- 

 ranean source of heat, i. e., was a phreatic explosion as defined 

 by Daly. 



Once set in motion, however, the mass behaved as a land- 

 slide and manifested all the characteristics of the Mageik Slide. 

 It was this aspect of the phenomena, rather than the explosion, 

 that caused the loss of life and damage to property, and hence 

 it was this that occupies a major share of the account of the 

 catastrophe. The following excerpts from the account are of 

 more than usual interest in connection with our problem: 



*Sekiva, S., and Kikuchi, Y. The Eruption of Bandai San. Jour. Col. Sci. 

 Imp. Univ. Tokyo. 3:91-172. 1889. 



