June, 1920] 



The Great Mageik Landslide 



351 



"While darkness as aforesaid shrouded the region, a mighty 

 avalanche of earth and rock rushed at terrific speed down the 

 mountain slopes, buried the Nagase Valley with its villages and 

 people, and devastated an area of more than 70 square kilo- 

 meters."* 



Recognizing that the main phenomenon of the eruption 

 was not properly volcanic, the authors go on, (p. 106): "The 

 main feature in the whole of this eruption was the deluge of 

 rock and earth. Notwithstanding the violence of the phenome- 



Photograph by Robert F. Griggs 



CHUNKS OF PEAT IN THE SLIDE DEBRIS. 



Near the terminus of the slide are great masses of peaty soil. In some cases the 

 chunks were thrown into rude windrows by the motion of the mass. 



non, and the completeness with which the mountain was 

 destroyed, the nature of the eruption was comparatively simple. 

 The destructive agency was merely the sudden expansion of 

 imprisoned steam unaccompanied by lava flows or pumice 

 ejection. * * * by far the greater mass of Kobandai was 

 just split into mighty fragments, which were thrown down 

 much after the manner of a landslide. * * * If we suppose 



*0p. cit. p. 104. 



