Oct 26, 2018
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 newly published 2018 update to the USGS National Volcanic Threat Assessment helps guide decision-making and prioritization among the U.S.’ active and potentially active volcanoes.
So how do we make choices on where to build or strengthen volcano monitoring networks and where more work is needed on emergency preparedness and response?
This newly published 2018 update to the USGS National Volcanic Threat Assessment helps guide decision-making and prioritization.
Map showing locations of all U.S. volcanoes with threat category designated by color. NVEWS is the National Volcano Early Warning System. USGS graphic.
The assessment focuses on the active and potentially active volcanoes in the U.S., analyzing their histories, hazards and the exposure of people, property and infrastructure to harm during the next eruption. The assessment uses 24 hazard and exposure factors to derive a score and volcanoes are grouped into five threat categories.
Lava fountains and channelized flow erupting from the fissure 8 spatter cone on Kīlauea Volcano’s lower East Rift Zone. Kīlauea ranked as the U.S. volcano with the highest threat score. The eruptive activity in 2018 and the destruction of residential subdivisions on its flanks are clear examples of why Kīlauea is a very high threat volcano. USGS photo taken June 25, 2018, by Ben Gaddis.
The update names 18 very high threat, 39 high threat, 49 moderate threat, 34 low threat, and 21 very low threat volcanoes. The volcanoes are in Alaska, Arizona, California, Colorado, Hawaii, Idaho, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming, American Samoa and the Commonwealth of the Northern Mariana Islands. The threat ranking is not a list of which volcano will erupt next. Rather, it indicates how severe the impacts might be from future eruptions at any given volcano.
Washington State Highway 504 steel bridge structure carried about a quarter mile downstream and partly buried by the May 18, 1980 mudflow from Mount St. Helens. Mount St. Helens is #2 on the threat rankings. USGS image by R.L. Schuster
The updates makes several changes to the 2005 assessment based upon (1) new age dates for volcanic products, and (2) updates to the hazard and exposure factors. As a result, some volcanoes were added or removed, and the threat ranking changed for others.
Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula on April 21, 1990. An encounter with an eruption cloud from Redoubt nearly brought down a passenger jetliner in 1989. Redoubt Volcano is #4 on the threat ranking. USGS photo by R. Clucas.
The volcanic threat assessment helps prioritize U.S. volcanoes for research, hazard assessment, emergency planning, and volcano monitoring.
The next big eruption could happen around your corner. Be ready or get prepared!
Thanks to: http://strangesounds.org