National Geographic : 2003 Jan
Quicksilver to ASh A serpentineflow barely six inches wide and 50feet long (above) meanders throughformations of smooth pahoehoe lava and rough aa lava, the same forms common in basalt lavas. 01 Doinyo Lengai's lavas break down so quickly that their age can be judged by theircolor. Black as oil when they emerge, they quickly shift to muddy browns, grays, andfinally frosty white within a few days. Looking like a spotted sala manderfrozen in stone, apahoehoeflow (right) reveals the lava'sfragility: Even raindropsaccelerateits decomposition. The interiorof a collapsedhornito hides a lava lake (below). Carbondioxide in the lava creates bubbles the size of basket balls that slowly expand, then burst,plasteringthe rim with spray. This splatter builds thefoundation of a new cone.