http://gallery.usgs.gov/videos/114

USGS ScientistinCharge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions to explain volcanic eruptions at Yellowstone: When was the last supereruption at Yellowstone?", "Have any eruptions occurred since the last supereruption?", "Is Yellowstone overdue for an eruption?", "What does the magma below indicate about a possible eruption?", "What else is possible?", and "Why didn't you think the Yellowstone Lake earthquake swarm would lead to an eruption?"