Suggested citation and version history for: Diefenbach, A.K., Guffanti, Marianne, and Ewert, J.W., 2009, Chronology and references of volcanic eruptions and selected unrest in the United States, 1980-2008: U.S. Geological Survey Open-File Report 2009-1118, 85 p. [http://pubs.usgs.gov/of/2009/1118/]. Version 1.0, July 1, 2009 Initial release online at http://pubs.usgs.gov/of/2009/1118/