ScienceDaily (Dec. 7, 2011) — Yellowstone National Park sits on top of a vast, ancient, and still active volcano. Heat pours off its underground magma chamber, and is the fuel for Yellowstone's famous features -- more than 10,000 hot springs, mud pots, terraces and geysers, including Old Faithful. But expected development by energy companies right outside Yellowstone's borders have some fearing that Old Faithful could be cheated out of its energy.
http://www.sciencedaily.com/releases/2011/12/111207175738.htm