Revision History for U.S. Geological Survey Fact Sheet 2006-3139	

By Cynthia A. Gardner and Marianne C. Guffanti

U.S. Geological Survey’s Alert-Notification System for Volcanic Activity

---------------------------------------------------------
Version 1.0 posted online March 2, 2007, reprinted 2014

--------------------------------------------------------
Version 2.0 revised and reposted April 23, 2025

Text was updated to reflect current operations of the alert-notification system

Photographs updated to reflect more recent volcanic eruptions

Layout redesigned and modernized