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Volcanoes pose many hazards to their surroundings, from ashfall, mudflows, lava flows, landslides, and associated earthquakes.  At least 54 of the United States' 169 active volcanoes pose major threats to public health and safety and to major industries such as agriculture, aviation, and transportation.


Ash from Mt. Redoubt, a remote volcano in Alaska, can threaten many aviation routes.Image Credit: U.S. Geological Survey/Photo by R.G. McGinsey

An explosive volcano can devastate its local area with mudflows, lava flows, and avalanches of hot rock and gas. Mudflows from ice-clad volcanoes like Mt. Rainier can travel tens of miles from the volcano. Some volcanic hazards, such as ash fall, can even impact areas hundreds of miles away. While it is not possible to forecast the exact time and place of an eruption, volcano monitoring is important in order to detect changes in a volcano's activity and provide warning of potential eruptions.   Read more

Frequently Asked Questions

Latest News

April 6, 2017 The Hazards Caucus Alliance, a network that supports the Congressional Hazards Caucus, hosted a briefing on April 6 about how geologic and hazards mapping and monitoring are used to prepare and protect communities from natural hazards. The Hazards Caucus provides congressional staff...
Paricutín Volcano
February 8, 2017 Senators Lisa Murkowski (R-AK), Maria Cantwell (D-WA), and Mazie Hirono (D-HI) introduced a bill to establish a National Volcano Early Warning and Monitoring System (S.346) on February 8. Lava flows, toxic gasses, mudslides, and large ash plumes from volcanoes pose a significant...
#MapOfTheDay! Interactive map of #volcanoes and current volcanic activity alerts from @USGS: http://bit.ly/1Fr07sC
#MapOfTheDay! Today the Critical Issues Program (@AGI_GeoIssues) shared an interactive map of volcanoes and current volcanic activity alerts across the United States from the Volcano Hazards Program at the U.S. Geological Survey (@USGS), which you can find at http://bit.ly/1Fr07sC. For over 300...
Paricutín Volcano
September 17, 2016 On September 17, Senate Committee on Energy & Natural Resources Chairman Senator Lisa Murkowski (R-AK) and Ranking Member Senator Maria Cantwell (D-WA) introduced their National Volcano Early Warning and Monitoring System Act (S.2056). On September 22, they discussed the bill...
Mount St. Helens
July 12, 2016 The Hazards Caucus Alliance, a network of organizations that promotes nationwide natural disaster resilience, held a briefing to highlight the role that science plays in protecting communities that are vulnerable to lahars. Introductory remarks from Senator Lisa Murkowski (R-AK) were...
Dynamic Planet glyph
November 19, 2014 On November 19, the House Natural Resources Committee Energy and Mineral Resources Subcommittee held an oversight hearing on U.S. preparedness for and response to volcanic hazards. The hearing was particularly timely because of the ongoing Kilauea eruption in Hawaii that threatens...

Case Studies & Factsheets


More than just volcanic eruptions Volcanic eruptions are a serious hazard. But at many stratovolcanoes in Washington, Oregon, Northern California, and Alaska, landslides and debris flows can be just as dangerous. Some of these - especially volcanic mudflows (lahars) - are directly triggered by...

Fig. 1. Although Glacier Peak normally can not be seen from any urban areas, this active volcano periodically erupts in an explosive catastrophic manner that could affect the lower part of the populated Skagit River Valley. Credit: D. Mullineaux, USGS

Defining the Problem Active volcanoes, such as Glacier Peak (Fig. 1), pose a variety of potential hazards. Like Mount Rainier (Fig. 2) and Mount St. Helens, the history of Glacier Peak includes explosive eruptions and lahars. Eruptions, earthquakes, or precipitation can trigger landslides that...

Research Database Publications

Cover of Volcanoes factsheet; Image credit: The Geological Society
2016, The Geological Society of London (GSL)
What is a volcano? Where are they and why are they there? This fact sheet, produced for a broad general audience, gives an overview of significant eruptions and the volcanic products that can cause such devastation.
Cover of RI2014-5; Source: Alaska Division of Geological & Geophysical Surveys
2014, Alaska Division of Geological & Geophysical Surveys (AK DGGS)
Fisher volcano, containing the largest Holocene caldera in the Aleutian volcanic arc, is an active volcano near the center of Unimak Island, about 120 kilometers southwest of Cold Bay and about 175 kilometers northeast of Dutch Harbor. The volcano is composed of numerous small volcanic centers...
Cover of sir20165164; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
Hawai'i's aquifers have limited capacity to store fresh groundwater because each island is small and surrounded by saltwater. Saltwater also underlies much of the fresh groundwater. Fresh groundwater resources are, therefore, particularly vulnerable to human activity, short-term climate cycles, and...
Cover of ofr-15-11; Source: Arizona Geological Survey
2015, Arizona Geological Survey (AZGS)
Approximately 60,000 years ago SP Crater, situated in the north- central part of the San Francisco volcanic field between Flagstaff and Grand Canyon, Arizona, erupted and flowed into a structural graben bound by late Quaternary faults. SP Crater is one of about 610 cinder cone volcanoes and 8 large...
Cover of b2185; Source: USGS
2002, U.S. Geological Survey (USGS)
Persistent unrest in Long Valley Caldera—characterized by recurring earthquake swarms, inflation of the resurgent dome in the central sections of the caldera, and emissions of magmatic carbon dioxide around Mammoth Mountain—during the last two decades and continuing into the 21st century emphasize...
Cover of Alaska Division of Geological & Geophysical Surveys Annual Report, 2014; Source: Alaska Division of Geological & Geophysical Surveys
2014, Alaska Division of Geological & Geophysical Surveys (AK DGGS)
Recently falling commodity prices have brought the state’s reliance on revenue from natural resources to the forefront. Alaska is not immune to national and world events and market changes. Many global commodity prices have fallen from peak values in the recent past to multi-year lows. Recent...
Cover of fs2016-3040; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
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...
Ash from Mt. Redoubt, a remote volcano in Alaska, can threaten many aviation routes.Image Credit: U.S. Geological Survey/Photo by R.G. McGinsey
2009, American Geosciences Institute (AGI)
After a series of five explosive eruptions from Sunday night through Monday morning, Alaska's Redoubt volcano quieted for about 15 hours Monday afternoon — long enough for scientists from the U.S. Geological Survey's Alaska Volcano Observatory to travel to the volcano to make observations and...
Cover for USGS FS 2014-3119 ; Source: USGS
2014, U.S. Geological Survey (USGS)
On May 22, 1915, a large explosive eruption at the summit of Lassen Peak, California, the southernmost active volcano in the Cascade Range, devastated nearby areas and rained volcanic ash as far away as 280 miles to the east. This explosion was the most powerful in a series of eruptions during 1914...
Cover of factsheet; Image credit: Hazards Caucus Alliance
2014, Hazards Caucus Alliance (HCA)
Approximately 170 active volcanoes lie within the borders of the United States and its territories. At least 54 of these volcanoes pose major and foreseeable threats to their surroundings and to industries that contribute to the national economy, such as agriculture, aviation, and transportation....