220 Ja(jgar — Yolcanologic Investigations at Kilauea. 



yolcano."^ An exceedingly fascinating field of speculation is 

 here brought into view, containing the possibility that the great 

 aa^ or block-lava, flows of Manna Loa, emergent under high gas 

 pressure and sudden release, are of tlie normal magma. The 

 intense and distributive oxidation of the gases through such a 

 flow, when released to atmospheric attack, and the ill adjusted 

 solidification and expansion-cooling effects from within outward, 

 added to the fact of acquisition of pahoehoe, or fluent lava, 

 characters near the vent, when furnace conditions are estab- 

 lished there, lend color to this view, which, however, cannot be 

 advanced as anything more than a suggestion in the present 

 stage of inquiry. t 



The application of the principles developed by this study of 

 Kilauea to the m.echanism of other volcanoes, and the termin- 

 ology of less local limitation to be adopted when stiff bench 

 magma and reheated fluent magma are recognized elsewhere, 

 form, topics too far-reaching to be discussed in this paper. The 

 writer has in preparation a contribution on these subjects. 



The question of viscosity vs. gas reaction has been the key- 

 note of volcanology since the eruption of Pelee in 1902, and 

 the classification of volcanoes in genetic series is dependent on 

 discovering, in this relation, the meaning of volcano distribu- 

 tion. 



The crags of bench magma described in this paper are much 

 like the steep peaks rising from the floor of many lunar craters, 

 and the selenologists can surely help to solve the volcano prob- 

 lem. I am convinced from what I have seen of Kilauea that the 

 problem will never be solved by expeditions or closet theoriz- 

 ings. The record of volcano process, as I have tried to show 

 all too briefly, involves the registration of change and measure- 

 ment of dimension in relation to passage of time. The only 

 sound mode of attack is through permanent laboratories in the 

 actual volcano field. Such laboratories, adequately equipped, 

 have not yet been established. 



* Since tills was written an extraordinary confirmation of the hypothesis 

 here stated was afforded by the east island (fig. 86), the base of which proved 

 to be typical block-lava of the Mauna Loa variety. This prior to Feb. 17, 

 1917, had been the Kilcmea lake-bottom. See Jour. Wash. Acad., 1917. 



f This Journal, xliii, pp. 255-288, April, 1917. 



Hawaiian Volcano Observatory, March 7, 1917. 



