"More than 40 active volcanoes occur in Alaska. This report summarizes historical data on those volcanoes, using information drawn from the more thorough and comprehensive U.S. Geological Survey (USGS) Open-File Report 98-582, Catalog of the Historically Active Volcanoes of Alaska. In Alaska, written historical records began about 1760, when Russian sailors and fur traders first explored the southern mainland coast and the Aleutian Islands. Many early accounts of volcanic eruptions are brief and incomplete, and numerous eruptions likely went unreported. Undoubtedly, some accounts mistakenly reported eruptions or misidentified the active volcano. Reports of low-level emission of steam and gas have been omitted."
USGS Fact Sheet 118-00
U.S. Geological Survey: http://www.usgs.gov/