Figure showing major air traffic routes (blue lines) Novarupta, and Novarupta's 1912 ash plume area (tan section.) Figure from Fierstein, Judy, and Hildreth, Wes, 2001, Preliminary volcano-hazard assessment for the Katmai volcanic cluster, Alaska: U.S. Geological Survey Open-File Report OF 00-0489, 50 p., 1 plate.