About Volcanoes

photo of hikers on a trail walking down a steep sided canyon of volcanic rocks and cinders
Hikers enjoying the dramatic colors and craters in Haleakalã National Park, Hawaiʻi.

Photo by Jon Schmitz, Haleakalã National Park, 2014 Share the Experience photo contest.

Explore Volcanic Features and Processes

National parks contain many of the best known and most scenic volcanoes in the United States: Mount Rainier, Crater Lake, Lassen Peak, Kīlauea, Sunset Crater Volcano, Yellowstone. Nineteen parks were set aside for their volcanic resources and 69 more parks contain volcanoes or volcanic deposits. People can experience the majesty of these volcanoes and volcanic resources by visiting national parks, and learn more about them by visiting the following sections of the Volcanoes, Craters, and Lava Flows website:

Volcanic Processes

Volcanic processes are among the most awesome natural phenomena on the planet and are responsible for shaping the landscapes of many national parks. Volcanic processes consist of all natural volcano-related activity that happens on volcanic landforms. Volcanic eruptions range from effusive emissions of lava flows to highly explosive eruptions that can devastate large areas and send ash columns high into the stratosphere. Volcanic processes also include phenomena that occur before eruptions such as volcanic earthquakes, and other events such as landslides and lahars that may occur during eruptions or have other triggering events. Volcanoes in 17 units of the National Park System have experienced prehistoric or historic eruptions.

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Related Links

Volcanic Eruptions | Eruption Classifications | Magmatic Eruptions | Phreatomagmatic (Hydrovolcanic) Eruptions | Phreatic Eruptions | Hawaiian-style Eruptions | Strombolian Eruptions | Vulcanian Eruptions | Sub-Plinian Eruptions | Plinian Eruptions | Ultra-Plinian Eruptions | Volcanic Explosivity Index | Volcanic Blasts | Historic & Prehistoric Eruptions | Lahars | Landslides

Volcanoes & Volcanic Landforms

Volcanoes or volcanic landforms are found in 37 national park areas. National park volcanoes range from the majestic Mount Rainier to the active Kīlauea Volcano in Hawai’i Volcanoes National Park, and from the nearly-pristince Sunset Crater Volcano to the deeply-eroded volcanic center in Pinnacles National Park. Volcanoes are the both the vent where molten rock material is erupted and the mountains or cones (edifices) built by those eruptions. Some types of volcanoes are massive like the shield volcanoes in Hawai’i Volcanoes and Wrangell-St. Elias national parks, and others form only low hills but emit lava flows that cover large areas, like those in Craters of the Moon and El Malpais national monuments.

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Related Links

Types of Volcanoes | Cinder Cones | Composite Volcanoes (Stratovolcanoes) | Shield Volcanoes | Calderas | Explosive Calderas | Summit Calderas | Resurgent Calderas | Older Caldera Complexes | Nonexplosive Calderas | “Super Volcanoes” | Domes | Maars & Tuff Rings | Fissure Volcanoes | Volcanic Fields—Momogenetic | Volcanic Landscapes | Volcanic Resources Summary—Capulin Volcano National Monument | Volcanic Resources Summary—El Malpais National Monument | Volcanic Resources Summary—Lassen Volcanic National Park | Erosional Volcanic Landforms | Volcanic Necks and Plugs | Volcanic Inverted Topography

Craters & Other Volcanic Features

All volcanoes have at least one feature in common—one or more vents where molten rock material and volcanic gases are erupted. Beyond that, volcanoes are diverse and have a range of sizes, and shapes, features, and deposits. Many volcanoes have craters at their summits and sometimes at locations on their flanks. Some craters contain water lakes, and other craters may host lakes of lava. Many active volcanoes have fumaroles and other geothermal features.

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Related Links

Anatomy of a Volcano | Volcanic Craters | Vents | Crater Lakes | Lava Lakes | Fumaroles | Geothermal Features

Lava Flows & Other Volcanic Deposits

Volcanoes erupt lava flows that travel across landscapes and sometimes even build new islands. They also erupt explosively and send columns of ash and tephra high into the atmosphere or send gravity currents of ash and other pyroclastic debris and superheated gases roaring down their slopes. Different types of lava flows have characteristic features that provide information of how they erupted and how they flowed and reshaped the land. Pyroclastic deposits range from large volcanic bombs that fell on the slopes of a cinder cone, to ignimbrites deposited by pyroclastic flows, and to ash fall deposits that may be found great distances from the source of the eruption.

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Plate Tectonics

Plate tectonics provides “the big picture” of geology; it explains how mountain ranges, earthquakes, volcanoes, shorelines, and other features tend to form where the moving plates interact along their boundaries, and at hotspots.

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Related Links

Convergent Plate Boundaries—Subduction Zones | Divergent Plate Boundary—Continental Rift | Hotspots | Inner Earth Model | Evidence of Plate Motions

Park Articles and Stories

View a variety of articles and stories from around the NPS about volcanic features and processes, as well as volcano parks' science and management activities.

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Site Index and Credits

[Site Under Development]

Volcanoes, Craters & Lava Flows [Home Page]

  1. Volcanic Necks and Plugs (Article)

  2. Volcanic Inverted Topography (Article)


Volcanoes, Craters & Lava Flows (2022) [Site Under Development]

Text by Allyson C. Mathis (geologist / science writer). Contributors: Tom Casadevall (USGS), Tim Connors (GRD), Ed Robeck (AGI), Vincent Santucci (GRD), Trista Thornberry-Ehrlich (CSU). Project lead / web development: Jim Wood (GRD).

Produced under a Cooperative Agreement for earth science education between the National Park Service's Geologic Resources Division and the American Geosciences Institute.

Citing pages from NPS websites:

National Park Service (Year, Month date—from "last update" at the bottom of the webpage). Page title—from the top of the webpage, but in sentence-case and italics. NPS.GOV. Https://www.nps.gov/subjects/volcanoes/...—Use the full address of the webpage you're citing with no puncuation after the address


Last updated: December 14, 2022