Depending on the context, volcanic eruptions are either terrifying or transfixing—sometimes both, but rarely neither. The opportunity to safely view the otherworldly spectacle of lava rarely fails to ignite a child-like, giddy wonder. The damage currently being done by a lava flows in the Cape Verde Islands, on the other hand, is heart-breaking.
We study these things because they are both lovely and terrible. We want to see a lava flow spill across a snowfield out of curiosity, and we want to better understand the hazards surrounding snow-capped volcanoes out of caution. Benjamin Edwards of Dickinson College and Alexander Belousov and Marina Belousova of Russia’s Institute of Volcanology and Seismology got the opportunity to witness one of these events last year in Russia’s Kamchatka Peninsula. For nine months, Tolbachik spewed basaltic lava flows that ultimately covered 40 square kilometers, reaching as far as 17 kilometers from their source.
The lava flows came in two flavors, known to geologists by Hawaiian names. (While frozen Kamchatka doesn’t exactly evoke coconuts and grass skirts, these lavas are similar to those of the Hawaiian volcanoes.) First there’s ‘a’a (pronounced as a staccato “AH-ah”), which ends up a chunky, blocky crumble of basalt. The other is pahoehoe (roughly “puh-HOY-hoy”, which is how volcanologists answer the phone), which flows more like thick batter and can solidify into a surface resembling a pile of ropes.