1980年以前圣海伦火山的爆发历史 http://pubs.usgs.gov/fs/2005/3045/ Pre-1980 Eruptive History of Mount St. Helens, Washington Pre-1980 Eruptive History of Mount St. Helens, Washington Pre-1980 Eruptive History of Mount St. Helens, Washington pubs.usgs.gov Pre-1980 Eruptive History of Mount St. Helens, Washington USGS Index Page (html) http://pubs.usgs.gov/fs/2005/3045/