VOLCANOES AND IGNEOUS INTRUSIONS 



307 



volcanoes are known in which the lava 

 forced out of craters near the close of 

 eruptions assumed the form of steep- 

 sided cones. 



(5) Bandai-san. — An eruption in 

 which, so far as known, no lava was 

 discharged took place in 1888 in Japan. 

 For 1000 years Bandai-san, a volcanic 

 cone 2000 feet high, had been dormant, 

 when suddenly a terrific explosion blew 

 away the greater part of the mountain 

 (Fig. 301). Since this one explosion, 

 the volcano has shown no signs of 

 activity. The catastrophe was due to 

 the heating of water which had perco- 

 lated from the surface, and was in fact 

 a steam explosion. A priest living on 

 the mountain reported that the gases 

 surrounding him were respirable. 



Fig. 300. — The spu.e of Mt. Puee, 

 Martinique, French West Indies, 1902. 



In all of the eruptions of the 

 explosive type, dust, cinders, (After E. O. Hovey.) 

 and usually bombs are thrown 



out; earthquakes are prevalent previous to and accompanying the 



eruptions; sometimes lava is poured out from the crater or from 



...... fissures in the mountain side. 



The greatest eruptions often occur 

 after long periods of inactivity. 



77. The Quiet or Hawaiian Type 



lwUe 



Fig. 301. -Volcano Bandai-san. The . The Hawaiian type of volcano 

 portion enclosed by the dotted line was IS in marked contrast to the ex- 

 blown off during an eruption lasting less plosive or Vesuvian type, since in 

 than two hours. The height of the cliff 1 r 



is about 1500 feet. (After Hobbs.) the former e ™ptlons are not ac- 



companied by severe explosions, 

 but consist largely in the gentle welling-out of lava from the crater 

 or from mouths in the sides of the mountain. In general, the 

 features most characteristic of volcanoes of this type are: (1) their 

 gentle slopes which do not average more than 7 degrees, (2) the 

 large size of their craters or calderas, 1 (3) the quietness of the erup- 

 tions, (4) the fusibility of the (basic) lava which they discharge, and 

 (5) the absence of severe earthquakes during and preceding eruptions. 



See footnote on p. 309 for restricted use of term colder a. 



