U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2016–3040

July 2016 Printed on recycled paper

Cemetery Rd.

transfer station

destroyed house

U.S. Geological Survey 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 have 

the potential to erupt again. 

Consequences of eruptions from 

U.S. volcanoes can extend far 

beyond the volcano’s immediate 

area. Many aspects of our daily life 

are vulnerable to volcano hazards, 

including air travel, regional 

power generation and transmission 

infrastructure, interstate 

transportation, port facilities, 

communications infrastructure, and 

public health. The U.S. Geological 

Survey has the Federal responsibility 

to issue timely warnings of potential 

volcanic activity to the affected 

populace and civil authorities. The 

Volcano Hazards Program (VHP) 

is funded to carry out that mission 

and does so through a combination 

of volcano monitoring, shortterm warnings, research on how 

volcanoes work, and community 

education and outreach. 

(Above) Pavlof volcano, on the southwestern end of the Alaska Peninsula, erupted in 2016. 

Impacts in March and May from volcanic ash hazards required cancellation of more than 100 

commercial and passenger flights. Photograph taken at 20,000 feet on March 28, 2016, from 

Coast Guard 1713, a HC-130 H Hercules based at Air Station Kodiak, courtesy of Lieutenant 

Commander Nahshon Almandmoss. (Below) Lava flows from Kīlauea Volcano encroached 

on the town of Pāhoa in November 2014, threatening infrastructure, businesses, and homes. 

Every day, VHP scientists work to 

enhance public safety and minimize social 

and economic disruption from volcanic 

unrest across thousands of miles in the 

United States. We monitor the progress of 

lava flows and persistent gas issuing from 

Kīlauea volcano, which poses hazards to 

communities across the Hawaiian Islands. 

We provide forecasts of ashfall from 

dozens of persistently active volcanoes 

in Alaska’s Aleutian Arc and work in 

coordination with the National Weather 

Service Volcanic Ash Advisory Centers to 

track ash clouds that threaten communities 

and trans-Pacific aviation. We monitor 

activity to detect the earliest signs of 

reawakening at dangerous volcanoes such 

as Mount St. Helens, Mount Rainier, and 

Mount Hood, which directly threaten 

more than 300,000 people in the Pacific 

Northwest. We conduct fundamental 

research to better understand some of 

the largest eruptions on Earth, such as 

those that occurred at Yellowstone—a 

still-active geothermal spectacle in the 

mid-Continent. We ensure hazards are 

known and communicated for Mount 

Shasta, Long Valley Caldera, and a dozen 

other volcanoes in California that pose 

threats to populations, agriculture, and 

utility and transportation corridors.
Hayes

Okmok

Griggs Katmai Mageik

Martin

Pavlof

Dutton

Seguam

Kanaga

Iliamna

Kaguyak

Trident

Gareloi

Wrangell

Westdahl

Churchill

Aniakchak

Veniaminof

Shishaldin

Great Sitkin

Pavlof Sister

Atka

Ugashik-Peulik

Semisopochnoi

Spurr

Akutan

Redoubt

Makushin

Augustine

0 500 1,000 Miles

0 500 1,000 Kilometers

Pagan

Agrigan

Anatahan

Alamagan

0 50 Miles

0 50 Kilometers

Very High

High

Moderate

Low

Very Low

NVEWS Volcano Threat Ranking

Explanation

California (CalVO)

Cascades (CVO)

Yellowstone (YVO)

Hawaiian (HVO)

Alaska (AVO)

Volcano Observatory

Area of Responsibility

Yellowstone

Salton Buttes

Medicine Lake

Mono-Inyo Chain

Mount Adams

Clear Lake Volcanic Field

Crater Lake

Glacier Peak

Newberry

Long Valley Caldera

Lassen Volcanic Center

Mount Hood

Mount Baker

Mount Shasta

Three Sisters

Mount Rainier

Mount St. Helens

Hualalai

Mauna Loa Kilauea

0 250 Miles

0 250 Kilometers

USGS Volcano Hazards 

Program operates five Volcano 

Observatories in assigned 

geographic areas. Volcanoes 

are found throughout the Pacific 

Ocean basin and the western half 

of the United States. Staff at the 

Volcano Observatories monitor and 

study these volcanoes, conduct 

research on how volcanoes 

work, and assess long- and 

short-term hazards in the United 

States and Commonwealth of 

the Northern Mariana Islands. 

Volcano Observatory scientists 

work with Federal, State, local, and 

academic partner organizations 

to better understand and prepare 

communities for volcanic unrest 

and eruption. Observatories are 

responsible for communicating 

scientific findings to emergencymanagement professionals and the 

public via volcanic activity alerts 

and “timely warnings” of potential 

volcanic hazards. 
National Volcano Early Warning 

System Ensures Volcanoes are 

Appropriately Monitored

The National Volcano Early Warning 

System (NVEWS) is an ongoing 

national effort by the VHP and its 

affiliated partners to ensure that all 

U.S. volcanoes are monitored at levels 

matching the threats that they pose.

VHP scientists recognize that roughly 

one-half of the nation’s 170 young 

volcanoes are potentially hazardous 

because of the manner in which 

they erupt and the presence of large 

at-risk communities and infrastructure 

downwind and downstream. Many 

of these volcanoes have insufficient 

monitoring systems or outdated 

equipment. The NVEWS plan ranks the 

volcanoes by threat level and prioritizes 

needs for upgraded monitoring networks 

so that hazardous volcanoes can be well 

understood in advance of reawakening. 

Adequate monitoring ensures that if 

communities and infrastructure are in 

harm’s way, we will be able to deliver 

early and accurate notifications of 

developing hazards so that proper actions 

can be taken to save lives and property.

Decision-makers Receive Rapid 

Notifications and Information 

Based on Research and 

Monitoring

Active volcanoes are complex natural 

systems that operate at extremely 

high temperatures and pressures. 

They originate deep within the Earth 

and dynamically evolve as magma 

migrates to the surface. Understanding 

volcanic behavior requires the focus of 

multiple scientific disciplines. Scientists 

scrutinize signals such as small 

magnitude earthquakes, swelling of the 

ground, and rates and compositions of 

gas and water discharge. They interpret 

these signals while considering current 

knowledge about how volcanoes behave, 

the history of volcanic activity, and the 

geologic structure of nearby mountains 

and tectonic plates.

Fundamental Research Helps Forecast 

Future Hazard Potential

Fundamental research of volcanic 

processes before, during, and after 

eruptions allows scientists to understand 

volcano behavior and to forecast how 

eruptions might impact communities 

and ecosystems. VHP scientists conduct 

extensive field investigations, perform 

laboratory analyses, and develop 

physics-based process models. Together, 

these fundamental research activities 

help us understand events in past 

eruptions and develop new hypotheses 

about the inner workings of volcanoes. 

Research results improve eruption 

forecast accuracy and our predictions 

of the paths taken by destructive lava 

flows, landslides, lahars, and ash. They 

also form the basis for formal volcanic 

hazard assessments, guidance provided 

to emergency officials, and prioritization 

of volcano monitoring needs. VHP 

research is published in more than 100 

scientific articles annually, and it is 

recognized and applied globally.

Monitoring Networks Deliver Critical 

Information

VHP scientists track volcanic activity 

by installing networks of sensitive 

instruments that continuously record 

the earthquakes, ground motion, and 

chemical changes that herald the onset 

of volcanic unrest. When deployed in 

periods of volcanic quiet, we learn a 

volcano’s normal behavior. Therefore, 

when signals shift away from normal, 

we are able to more accurately detect 

signs of reawakening. Monitoring 

data also help us to evaluate whether 

a volcanic eruption is building up or 

calming down and to identify how 

explosive or hazardous an eruption 

might be. By relaying this information 

to authorities, VHP scientists provide 

guidance and important lead-time for 

successful evacuations, closures, and 

other mitigation actions.

Hazard Assessments Inform Planning, 

Preparedness, and Mitigation Decisions 

Volcanic eruption hazards are numerous 

and widespread. Wind-blown ash and 

volcanic gases can paralyze National 

airspace, disrupt power grids, and 

trouble population centers thousands 

of miles downwind for days or more. 

Lahars (volcanic mudflows), floods, 

and high sedimentation rates can 

inundate communities and sever critical 

transportation corridors downstream. 

Lava and pyroclastic flows (avalanches 

of hot rock and gases) can devastate 

nearby areas downslope from volcanic 

vents. 

To mitigate volcanic hazards, VHP 

scientists develop long- and short-term 

volcano hazards assessments. Long-term 

assessments combine known eruptive 

histories with computational models of 

hazards to identify areas at risk. These 

assessments are released as highresolution hazards-zonation maps with 

accompanying explanations. Long-term 

assessments form the basis for designing 

effective monitoring networks and guide 

local authorities in developing land-use 

and emergency preparedness plans. 

During an eruption, VHP scientists 

use long-term hazards assessments 

as a foundation for building day-today scenarios of potential eruption 

progress called short-term assessments. 

These products incorporate real-time 

monitoring data with hazards models 

based on current conditions

Practicing Preparedness and Eruption 

Response Promotes Community Resilience

The VHP works with Federal, State, and 

local officials to increase awareness of 

volcanic hazards and to help mitigate 

their effects. It is impossible to prevent 

a volcanic eruption from occurring, but 

impacts to communities are dramatically 

reduced when people know how to 

prepare for eruptions and where to get 

guidance during volcanic unrest. VHP 

personnel prepare educational materials 

and organize in-person training events 

specifically tailored to the needs of 

people at risk, emergency managers, and 

first responders.
ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

http://dx.doi.org/10.3133/fs20163040

Authors: 

Wendy K. Stovall, Aleeza M. Wilkins, 

Charles W. Mandeville, and Carolyn L. Driedger

For more information:

U.S. Geological Survey, 

12201 Sunrise Valley Dr., MS 905 

Reston, VA 20192

http://volcanoes.usgs.gov/

Publishing support provided by the 

U.S. Geological Survey, 

Science Publishing Network, 

Tacoma Publishing Service Center

In the last 50 years, impacts from 

eruptions and persistent degassing 

of volcanoes in Alaska, Washington, 

Hawaii, and the Commonwealth of 

the Northern Mariana Islands have 

cost billions of dollars. Because of 

population growth and development 

near volcanoes, the next eruption 

in the United States could affect 

millions of people. The economic 

sectors that have been affected by 

volcanic unrest in the last 50 years 

include:

• Agriculture

• Aviation/Airports

• Energy production

• Fishing

• Housing 

• Human health

• Port facilities

• Refineries

• Transportation/Rail and Road

• Water supply and quality

Where to Find U.S. Volcano Information

Volcano Hazards Program Website: 

volcanoes.usgs.gov

Volcano Notification Service: 

volcanoes.usgs.gov/vns

U.S. Geological Survey Volcanoes 

Facebook: www.facebook.com/

USGSvolcanoes

Volcano Hazards Program 

Communications Support National 

Disaster Preparedness 

During a volcanic event, volcanohazard information must be 

communicated quickly and accurately. 

The VHP promotes situational 

awareness through specific objectives: 

• Issues authoritative forecasts and 

status updates of volcanic activity via 

structured messages to the Federal 

Aviation Administration, National 

Weather Service, and state and local 

emergency management authorities.

• Investigates and rectifies reports of 

unrest and eruption that are false or 

misleading.

• Provides access to volcanic 

information and real-time data to the 

public via websites, social media, and 

subscription services. 

• Participates in targeted volcanohazard education and planning 

activities. With this information, 

officials and the public can make 

informed decisions and take 

appropriate actions during a crisis.

Partnerships between VHP staff and 

emergency response professionals 

strengthen coordination and 

communication during a volcanic 

crisis. Inter-agency groups develop and 

exercise emergency coordination plans 

together, well ahead of volcanic unrest. 

Under the guidance of the Department 

of Homeland Security’s National 

Incident Management System, VHP 

staff work regularly with emergency 

managers to identify and to practice the 

roles they will assume during a crisis.

Volcano Disaster Assistance 

Program Aims to Avert Volcanic 

Disasters and Advance Science 

Diplomacy

The Volcano Disaster Assistance 

Program (VDAP) is a cooperative 

partnership between the U.S. Geological 

Survey and the U.S. Agency for 

International Development Office of 

Foreign Disaster Assistance. VDAP staff 

work to reduce volcanic risk, primarily 

in developing nations with substantial 

volcano hazards, by invitation of the 

host country. They assist through three 

main activities: eruption response, 

training and technology transfer, and 

long-term assessment of in-country 

hazards. Since its formation in 1986, 

VDAP eruption responses have also 

helped protect U.S. strategic assets and 

critical infrastructure deployed overseas.

Scientific exchanges between the VDAP 

foreign and VHP domestic programs 

provide mutual benefits. VHP scientists 

assist with VDAP activities in foreign 

locations, including installation of 

monitoring systems, scientific research 

exchange, outreach, and interpretation of 

monitoring data to improve forecasting. 

Because VDAP is persistently engaged 

with active volcanic unrest and eruptions 

around the world, when domestic crises 

occur, VDAP staff members are able to 

provide global perspective and a breadth 

of eruption-response experience. The 

experience gained by VHP staff at active 

volcanoes overseas is invaluable for the 

interpretation of volcanic unrest and to 

aid domestic response activities. 

U.S. Geological Survey Volcano 

Hazards Program Keeps Watch 

to Ensure Safety

Most of the 170 volcanoes within the 

borders of the United States and its 

territories will erupt again. For many 

people, the concern about future 

eruptions from their local volcanoes 

is diminished by a sense of everyday 

normalcy, the volcano’s natural beauty, 

and uncertainties surrounding when the 

next eruption could occur. Yet, it is the 

duty of the VHP to remain vigilant–

learning about past eruption histories 

and connecting them to potential 

hazards, working with authorities, 

and issuing necessary warnings in the 

interest of public safety.