The USGS Volcano Hazards Program: Assess, Forecast, Prepare, Engage

At least 170 volcanoes in 12 states and 2 territories have erupted in the past 12,000 years and could erupt again. Their effects can reach far beyond the mountain: air travel, power generation and transmission, interstate transportation, ports, communications and public health are all vulnerable.

The U.S. Geological Survey has the federal responsibility to warn the public and civil authorities of possible volcanic activity. Its Volcano Hazards Program (VHP) does so through monitoring, short-term warnings, research into how volcanoes work, and education and outreach.

Pavlof volcano, Alaska Peninsula, erupting on March 28, 2016, seen at 20,000 feet from a Coast Guard HC-130; its ash forced cancellation of more than 100 flights that spring. U.S. Coast Guard.

Across the country

• Hawaii: tracking lava flows and gas from Kīlauea, which threaten communities across the islands.
• Alaska: forecasting ashfall from dozens of persistently active Aleutian volcanoes and, with the National Weather Service's Volcanic Ash Advisory Centers, tracking ash clouds that threaten communities and trans-Pacific aviation.
• Pacific Northwest: watching for the first signs of reawakening at Mount St. Helens, Mount Rainier and Mount Hood, which directly threaten more than 300,000 people.
• Yellowstone: researching some of the largest eruptions on Earth at a still-active geothermal system.
• California: making sure hazards are known at Mount Shasta, Long Valley Caldera and a dozen others near people, farms and utility and transportation corridors.

The five USGS volcano observatories — Alaska, California, Cascades, Hawaiian and Yellowstone — and U.S. volcanoes ranked from very low to very high threat. USGS.

Monitoring matched to the threat

The National Volcano Early Warning System (NVEWS) is a national effort to monitor every U.S. volcano at a level matching its threat.

• Instruments: networks record earthquakes, ground motion and chemical changes continuously. Deployed during quiet times, they reveal a volcano's normal behavior, so departures stand out.
• During unrest: data show whether an eruption is building or calming, and how explosive it may be — giving authorities lead time for evacuations and closures.

Research behind the forecasts

Volcanoes are complex systems of extreme heat and pressure, evolving as magma rises. Scientists read signals — small earthquakes, ground swelling, changes in gas and water discharge — against each volcano's history and geology. Through fieldwork, laboratory analyses and physics-based models, VHP research improves forecasts of eruptions and the paths of lava flows, landslides, lahars and ash. It underpins hazard assessments, guidance to officials and monitoring priorities, and appears in more than 100 scientific articles a year.

The hazards are many and widespread:

• ash and gas can paralyze airspace, disrupt power grids and affect cities thousands of miles downwind for days;
• lahars (volcanic mudflows), floods and heavy sedimentation can bury communities and cut transportation corridors downstream;
• lava and pyroclastic flows — avalanches of hot rock and gas — can devastate areas below the vent.

Lava from Kīlauea approaching Pāhoa, Hawaii, in November 2014. USGS.

Hazard assessments

• Long-term: eruptive histories combined with computer models of hazards, published as high-resolution hazard-zone maps. They guide monitoring design and local land-use and emergency planning.
• Short-term: during an eruption, day-to-day scenarios that combine the long-term assessment with real-time data.

Preparing communities

Eruptions can't be prevented, but their impact drops sharply when people know how to prepare and where to get guidance. VHP staff make educational materials and run training for people at risk, emergency managers and first responders, and plan and rehearse crisis roles with them under the Department of Homeland Security's National Incident Management System.

In a crisis, the VHP:

• sends authoritative forecasts and status updates to the Federal Aviation Administration, the National Weather Service, and state and local emergency managers;
• checks and corrects false or misleading reports;
• shares information and real-time data through websites, social media and subscription alerts;
• joins targeted education and planning.

The stakes: in the last 50 years, eruptions and gas in Alaska, Washington, Hawaii and the Northern Mariana Islands have cost billions of dollars, hitting agriculture, aviation, energy, fishing, housing, health, ports, refineries, road and rail, and water supply. With growth near volcanoes, the next U.S. eruption could affect millions.

Helping abroad

The Volcano Disaster Assistance Program (VDAP), a partnership of USGS and the U.S. Agency for International Development's Office of Foreign Disaster Assistance, works — by invitation — to reduce volcanic risk, mostly in developing nations, through eruption response, training and technology transfer, and hazard assessment. Since 1986 its responses have also protected U.S. strategic assets overseas. VDAP's constant experience with eruptions worldwide gives domestic crises a global perspective, and VHP scientists help abroad in turn.

Keeping watch

Most of the 170 U.S. volcanoes will erupt again. Everyday normalcy, scenic beauty and uncertain timing can dull people's concern — which is why the VHP stays vigilant: learning from past eruptions, working with authorities, and warning the public. More: USGS Volcano Hazards Program.

Sources

Based on U.S. Geological Survey Volcano Hazards Program—Assess, Forecast, Prepare, Engage, by Wendy K. Stovall, Aleeza M. Wilkins, Charles W. Mandeville and Carolyn L. Driedger, U.S. Geological Survey Fact Sheet 2016–3040 (DOI; publication page). Its lists and the photographs and map are restored from the fact sheet's PDF; the Pavlof photograph is courtesy of Lieutenant Commander Nahshon Almandmoss, U.S. Coast Guard. A work of the United States government in the public domain.