The USGS Volcano Hazards Program

Overview
Goals of the program
Role of the Volcano Observatories
References
The information presented above is derived from USGS Circular1073 Living with Volcanoes: The U.S. Geological Survey's Volcano Hazards Program authored by T.L. Wright and T.C. Pierson. This publication is free on application from: 
    Books and Open-File Reports Section
    U.S. Geological Survey
    Federal Center, Box 25425
    Denver, CO.  80225
Information about and from the other USGS volcano observatories