National Volcano Early Warning System - monitoring volcanoes according to their threat

The United States has about 170 young volcanoes. Roughly half of those are dangerous because of the manner in which they erupt and the communities within their reach. Currently, many of these volcanoes have insufficient monitoring systems, and others have obsolete equipment. The goal of the NVEWS plan is to ensure that the most hazardous volcanoes will be properly monitored well in advance of the onset of activity, making it possible for scientists to improve the timeliness and accuracy of hazard forecasts and for citizens to take proper and timely action to reduce risk.

In addition, the NVEWS plan seeks to improve a number of capabilities of the US volcanology community through the following elements: 1) increased partnerships with local governments and emergency responders, 2) grants to universities and other groups for cooperative research to advance volcano science, monitoring technologies, and mitigation strategies, 3) added staffing and automation to improve 24/7 monitoring of volcanoes, and 4) computer systems to distribute data to scientists, responding agencies, and the public, and to unify the systems currently used to monitor US volcanoes.

Volcanic threat potential helps to prioritize monitoring.

Volcanic threat is defined as the qualitative risk posed by a volcano to people and property. It combines volcanic hazards (the dangerous or destructive natural phenomena produced by a volcano) and exposure (the people and property at risk from the volcanic phenomena). To determine the overall threat ranking numerical values are assigned to the hazard and exposure factors at individual volcanoes. These factors are individually summed into a hazard score and an exposure score, which are then multiplied to generate the volcano's overall threat score. The resultant scores produce a relative ranking of U.S. volcanoes that can be grouped into five threat categories: Very High and High threat categories requiring the most robust monitoring coverage, a Moderate threat category requiring basic real-time monitoring coverage, and Low and Very Low threat categories requiring lesser degrees of monitoring.

The overall result of the 2005 NVEWS assessment was the identification of 57 priority volcanoes undermonitored for the threats posed and thus targets for improved monitoring networks. Priority targets in this table may have changed since the 2005 assessment as incremental monitoring improvements have been made.

Regional Volcano Monitoring Priority

Source: 2018 update to the U.S. Geological Survey national volcanic threat assessment