106 EARTH FEATURES AND THEIR MEANING 



The two great active vents are Mokuaweoweo (on Mauna Loa) 

 and Kilauea, distinct volcanoes notwithstanding the fact that their 

 lava extravasations have been merged in a single mass. The rim 

 of the crater of Mauna Loa is at an elevation of 13,675 feet above 



the sea, whereas that of Kilauea 

 is less than 4000 feet and ap- 

 pears to rest upon the flank of 

 the larger mountain (Figs. 100 

 and 101). Although one crater 

 is but 20 miles distant from the 

 other and nearly 10,000 feet 

 lower, their eruptions have ap- 

 parently been unsympathetic. 

 Nowhere have still active lava 

 mountains been subjected to 

 such frequent observations ex- 

 tending throughout a long pe- 

 riod, and the dynamics of their 

 FIG. 100. Map of Hawaii and the lava eruptions are fairly well under- 



volcanoes of Mokuaweoweo (Mauna gtood. To put this before the 



reader, it will be best to con- 

 sider both mountains, for 

 though they have much in common, the observations from one are 

 strangely complementary to those of the other. The lower crater 



Loa) and Kilauea (after the government 

 map by Alexander). 



FIG. 101. Section through Mauna Loa and Kilauea. 



being easily accessible, Kilauea has been often visited, and there 

 exists a long series of more or less consecutive observations upon 

 it, which have been assembled and studied by Dana and Hitch- 

 cock. The place of outflow of the Kilauea lavas has not generally 

 been visible, whereas Mokuaweoweo has slopes rising nearly 14,000 

 feet above the sea and displays the records of outflow of many 

 eruptions, some of which were accompanied by the grandest of 

 volcanic phenomena. 



Lava movements within the caldron of Kilauea. The craters 

 of these mountains are the largest of active ones, each being in 



