Volcanic threat assessment helps prioritize risk reduction efforts at U.S. volcanoes

Since 1980, there have been 120 eruptions and 52 episodes of notable volcanic unrest at 44 U.S. volcanoes. When erupting, all volcanoes pose a degree of risk to people and infrastructure. However, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location.

The U.S. Geological Survey assesses active and potentially active volcanoes in the U.S., focusing on history, hazards and the exposure of people, property and infrastructure to harm during an eruption. The assessment uses 24 factors to obtain a score and threat ranking. The findings are in the newly published 2018 Update to the U.S. Geological Survey National Volcanic Threat Assessment.

The threat ranking is not an indication of which volcano will erupt next. Rather, it indicates how severe the impacts might be from future eruptions at any given volcano.

There are five ranked volcanoes in Hawaii. Kīlauea and Mauna Loa are ranked as very high threat, and Kīlauea is in the number one spot for the nation. Hualālai is high threat, and Haleakalā and Mauna Kea are moderate threat volcanoes. Lōʻihi is not ranked. Three low-threat volcanoes in American Samoa were added to the 2018 assessment and are part of the Hawaiian Volcano Observatory’s area of monitoring responsibility.

The volcanic threat assessment helps prioritize U.S. volcanoes for research, hazard assessment, emergency planning, and volcano monitoring. It is a way to help focus attention and resources where they can be most effective, guiding decision-making processes on where to build or strengthen volcano monitoring networks and where more work is needed on emergency preparedness and response.

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