Dave talks to Dave Hill, emeritus scientist for the United States Geological Survey and Margaret Mangan, director of the California Volcano Observatory . They talk about the history of volcanic unrest at Long Valley Caldera near Mammoth Lakes in the eastern Sierra Nevada. A series of earthquakes in the late '70s and 1980, coupled with the eruption of Mt. Saint Helens in May of 1980, led USGS scientists to issue volcanic hazard warnings. When picked up by the LA Times, the story caused social and