An Assessment of Volcanic Threat and Monitoring Capabilities in the United States: Framework for a National Volcano Early Warning System

A National Volcano Early Warning System NVEWS is being formulated by the
Consortium of U.S. Volcano Observatories (CUSVO) to establish a proactive,
fully integrated, national-scale monitoring effort that ensures the most
threatening volcanoes in the United States are properly monitored in advance of
the onset of unrest and at levels commensurate with the threats posed. Volcanic
threat is the combination of hazards (the destructive natural phenomena
produced by a volcano) and exposure (people and property at risk from the
hazards).

The United States has abundant volcanoes, and over the past 25 years the Nation
has experienced a diverse range of the destructive phenomena that volcanoes can
produce. Hazardous volcanic activity will continue to occur, and because of
increasing population, increasing development, and expanding national and
international air traffic over volcanic regions the exposure of human life
and enterprise to volcano hazards is increasing. Fortunately, volcanoes exhibit
precursory unrest that if detected and analyzed in time allows eruptions to be
anticipated and communities at risk to be forewarned with reliable information
in sufficient time to implement response plans and mitigation measures.

In the 25 years since the cataclysmic eruption of Mount St. Helens, scientific
and technological advances in volcanology have been used to develop and test
models of volcanic behavior and to make reliable forecasts of expected activity
a reality. Until now, these technologies and methods have been applied on an ad
hoc basis to volcanoes showing signs of activity. However, waiting to deploy a
robust, modern monitoring effort until a hazardous volcano awakens and an
unrest crisis begins is socially and scientifically unsatisfactory because it
forces scientists, civil authorities, citizens, and businesses into playing
catch up with the volcano, trying to get instruments and civil-defense
measures in place before the unrest escalates and the situation worsens.
Inevitably, this manner of response results in our missing crucial early stages
of the volcanic unrest and hampers our ability to accurately forecast events.
Restless volcanoes do not always progress to eruption; nevertheless, monitoring
is necessary in such cases to minimize either over-reacting, which costs money,
or under-reacting, which may cost lives.

[Summary provided by the USGS.]