Collaborative international volcano-response work has significantly strengthened the ability of the USGS to respond to future volcano crises within the United States. Participation in volcano emergencyies abroad has provided critical field tests for newly developed or modified monitoring instruments, led to the development of data-acquisition and data-analysis systems that run on widely available personal computers, and given USGS scientists additional experience in monitoring active volcanoes and communicating volcano-hazard information to emergency management officials and people living in hazardous areas. In the event of a crisis at a volcano in the United States, we now have the ability to supplement an existing network or install an entriely new one in a matter of days. This capabiltiy did not exist when Mount St. Helens became active in 1980 or during the 1985 crisis at Nevado del Ruiz volcano in Colombia.