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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

Mount St. Helens
May 20, 2018 On May 17, the Senate unanimously passed the National Volcano Early Warning and Monitoring System Act (S.346), sponsored by Senator Lisa Murkowski (R-AK). The bill establishes the National Volcano Early Warning and Monitoring System, under the authority of the U.S. Geological Survey (...
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

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
Surface and subsurface mapping of lahar and lahar runout deposits from Glacier Peak volcano has contributed important geologic information for land-management planning and emergency preparedness in the lower Skagit Valley. Defining the Problem Active volcanoes, such as Glacier Peak (Fig. 1), pose a...
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...

Geological Surveys Database Publications

2014, United States Geological Survey
Volcanic eruptions happen in the State of California about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have taken place in California in the past 1,000 yearsâEuro "most recently at Lassen Peak in Lassen Volcanic National Park (1914 to 1917) in...
2003, Alaska Division of Geological & Geophysical Surveys

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2000, Alaska Division of Geological & Geophysical Surveys

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1995, Alaska Division of Geological & Geophysical Surveys

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2004, Alaska Division of Geological & Geophysical Surveys

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2004, United States Geological Survey
Recent explosive eruptions at some of Alaska's 52 historically active volcanoes have significantly affected air traffic over the North Pacific, as well as Alaska's oil, power, and fishing industries and local communities. Since its founding in the late 1980s, the Alaska Volcano...
2014, Alaska Division of Geological & Geophysical Surveys

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1997, United States Geological Survey

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1964, Oklahoma Geological Survey
Irazu is an active volcano in Costa Rica, about 20 miles east of San Jose. The mountain is a caldera in which are a main crater and 4 volcanic cones. An eruption lasted from February 1723 to December 1726, after which the volcano was dormant for 191 years. There was further activity from 1917 until...
2011, United States Geological Survey
KÄ(lauea Volcano on the Island of HawaiâEuro ~i, though best known for its frequent quiet eruptions of lava flows, has erupted explosively many times in its history - most recently in 2011. At least six such eruptions in the past 1,500 years sent ash into the jet stream, at the cruising altitudes...