jaggar: thermal gradient at kilauea 



403 



on the side of the sinkholes, and relatively remote from the 

 conduit wells. The conduit gradient, to the writer's thinking, 

 should be different. 



As indicated in the figure, four heat zones are present, from 

 the hottest flame blast of burning gas in a high " blowing-cone" 

 on the border benches, downward to the lava lake bottom. 



The upper atmospheric zone shows a steep gradient of in- 

 creasing temperature from 1000°C. at the " bright lines" of 



TABLE 3 

 Group 3. Lower Lake Gradient (dots) 



the lava surface through the fountains, the confined grottoes 

 on the lake shore, and still more confined cupolas of driblet cones, 

 to the puffing vents where banners of flame play above these 

 cones as natural blow-pipes of burning sulphur and hydrogen. 

 These vents will fuse steel and hence reach a temperature of at 

 least 1350°. 



The zone of surface heating is a somewhat paradoxical region 

 at the lava surface where hot fountaining and hot "bright lines" 



