Lava Flows

photo of lava flow with molten rock
Visitors on an active lava flow at Kīlauea Volcano in Hawai’i Volcanoes National Park in 2016.

USGS Photo


Red-hot lava oozing from a volcanic vent during an eruption and slowly, but unstoppably, spreading across the landscape is one of the most awe-inspiring natural phenomena on our active Earth. Visitors to Hawai’i Volcanoes National Park may be able to witness flowing lava first-hand depending on the current activity of Kīlauea and appropriate safety considerations.

Young lava flows (typically less than a few thousand years old depending on the climate in the region where they are present) create inhospitable landscapes (badlands or malpais) where the rough rumbly terrain may have little vegetation and consist of a hazardous irregular topography of rough rock surfaces with loose boulders, fissures, clefts, and mounds. Sunset Crater Volcano, Craters of the Moon, and El Malpais national monuments contain young lava flows with these characteristics.

Older lava flows are subject to the same agents of weathering and erosion as other rock types. Since they are resistant to erosion, older lava flows may hold up cliffs like in Petroglyph National Monument, although they may have lost many of the features, such as pāhoehoe ropes or brecciated flow-top surfaces. But these older flows may still contain other features such as vesicles, columnar jointing, and lava tubes that preserve details of their emplacement during eruptions. And even ancient lava flows such as in Isle Royale and Shenandoah national parks still retain some volcanic features.


Lava flow: An outpouring of molten rock from a vent onto Earth's surface during an effusive volcanic eruption; also, the resulting solidified body of rock.

Composition and Viscosity

Together, composition and viscosity are two of most important characteristics of molten rock that determine the length and other characteristics of lava flows.

Basaltic lavas have low silica (45-52 weight %), are hot (2200°F; 1200°C), and have low viscosity, meaning that they flow easily. Basaltic lava flows may travel many miles (kms) from their vents, and up to hundreds of miles (kms) in the case of extremely large lava flows known as flood basalts.

Lavas that contain more silica are more viscous than basaltic ones. Lava flows with intermediate compositions do not travel as far as basaltic ones, and generally have flow surfaces consisting of large blocks of lava ripped apart by shearing during flowage.

Silicic lavas are extremely viscous. Most silicic lava flows are short and stubby, and many effusive eruptions of silicic lavas form domes instead of lava flows. Silicic lava flows are also not as nearly as hot as basaltic ones (1300–1600°F; 700–900°C).

Basaltic Lava Flows

Basaltic lava flows are by far the most common type of lava flows on Earth. In fact, approximately 90% of all lava flows have basaltic compositions. Most, if not all, of the 60 national parks that contain lava flows include basaltic ones.

Basaltic lava flows are so predominant that most of the features and characteristics typically associated with lava flows are restricted to only basaltic ones. Pāhoehoe and ʻa‘ā, which are lava flow morphological forms, are only present in basaltic lava flows. Likewise, lava tubes only form in basaltic flows.

Basaltic lava flows are erupted from shield volcanoes, fissure volcanoes, in monogenetic volcanic fields, and from vents at the base of cinder cone volcanoes. They may also be erupted from some composite volcanoes.

photo of a lava flow with molten rock and a rainbow
A double rainbow over an active pāhoehoe flow from Kīlauea Volcano in Hawai’i Volcanoes National Park in 2016.

USGS photo.

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Block Lava Flows

Intermediate (52–66 weight % SiO2; mostly basaltic andesite and andesite) lavas usually make block lava flows, where the surface of the flows are composed of large angular blocks. These lava flows are thicker than basaltic ones and have very steep flow fronts.

Lavas with intermediate compositions may be erupted from composite volcanoes, and sometimes other types of volcanoes.

photo of a lava flow, lake, forest and volcanic cone
The Fantastic Lava Beds are a block lava flow in Lassen Volcano National Park.

NPS photo.

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Silicic Lava Flows

Silicic (>66% weight % SiO2; dacite to rhyolite) lavas are relatively rare, but where they appear they tend to be very thick. Large volume lava flows are found in Yellowstone National Park.

photo of a rocky hillside viewed from above, a river flows in a valley below
The West Yellowstone lava flow was erupted about 114,000 years ago. This rhyolite lava flow is thick (1150 ft; 470 m) as is typical of viscous flows.

NPS photo by Jim Peaco.

Volcanic Domes

Because of their extremely high viscosity, many silicic lavas form volcanic domes in which erupted lava mounds up above a vent instead of spreading out in a flow. Lava domes commonly form in summit craters of composite volcanoes, and may also form volcanic edifices of their own.

photo of a rocky dome-shaped feature with steam venting from the top and sides
The active lava dome in the summit crater of Redoubt Volcano in June 2009.

USGS AVO photo by R. G. McGimsey.

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Columnar Jointing

Columnar jointing (e.g., regular sets of fractures) form during cooling of lava flows. The joints form while the flows are still hot, but have solidified. It is found in lava flows of all compositions.

Columnar jointed lava flow of the volcanic rocks of the Barrier Range on Takli Island in Amalik Bay. Katmai National Park & Preserve, Alaska.
Columnar jointed lava flow of the volcanic rocks of the Barrier Range on Takli Island in Amalik Bay. Katmai National Park & Preserve, Alaska.

NOAA photo.

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Lava Flows in National Parks

Lava flows are the most common volcanic resource found in national parks. Lava flows are present in at least 60 of the 89 volcanic parks (units of the National Park System containing volcanoes or volcanic deposits). Just over half of these parks contain the volcano or volcanic center where the lava flows were erupted. The rest of these parks either contain lava flows erupted from vents outside of the park area or older lava flows.

Some units like Isle Royale and Voyageurs national parks contain ancient lava flows that are more than a billion years old, and others contain lava flows that were erupted in historic times. Depending on the eruption status of Kīlauea and Mauna Loa in Hawai’i Volcanoes National Park, they may be emitting lava flows at any given time. Aniakchak National Monument and Lassen Volcanic, Lake Clark, and Katmai national parks contain lava flows that were erupted in historic times.

Lava flows found in national parks include some of the most voluminous flows in Earth’s history. The Keweenaw Basalts in Keweenaw National Historic Park are flood basalts that were erupted 1.1 billion years ago. Nez Perce National Historic Park, John Day Fossil Beds National Monument, Lake Roosevelt National Recreation Area and other units on the Columbia Plateau contain exposures of the Columbia River Basalts, flood basalts that were erupted mostly between 16.7 and 15.5 million years ago.

Aniakchak National Monument

Numerous eruptions of lava flows occurred before and after Aniakchak’s caldera-forming eruption 3,660 ± 70 years ago. The most recent eruption occurred in 1931 and produced a small lava flow as well as tephra and ash fall.

photo of a valley floor covered by lava
Post-caldera lava flow on the floor of Aniakchak Caldera.

USGS AVO photo by Wyatt Mayo.

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Bering Land Bridge National Preserve

Bering Land Bridge National Preserve contains two volcanic fields that contain young basaltic lava flows.

Aerial view of a large lava flow
Aerial view of the Lost Jim lava flow, the youngest lava flow in the Imuruk Lake Volcanic Field. This basaltic lava flow was erupted between 1,000 and 2,000 years ago.

USGS AVO photo by Jessica Larsen, University of Alaska Fairbanks, Geophysical Institute.

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Craters of the Moon National Monument

Craters of the Moon consists of three lava fields of mostly basaltic pāhoehoe lava flows, although some block and ʻa‘ā morphologies are present. Volcanic activity in the park occurred between about 15,000 and 2,100 years ago.

detail photo of ropy lava surface within a lava flow
Ropy pāhoehoe in Craters of the Moon National Monument, Idaho.

Photo by John St. James on Flickr.

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El Malpais National Monument

El Malpais National Monument is located within the Zuni-Bandera Volcanic Field, and contains five young basaltic lava flows that are notable for their length and diversity of surface features. The youngest of these is the McCartys Flow, erupted 3,900 years ago. It is the youngest in the state of New Mexico and has the site of important research that has produced significant insights into the emplacement mechanisms of basaltic lava flows.

Photo of a volcanic landscape with arid region vegetation
The McCartys lava flow. El Malpais National Monument, New Mexico.

NPS photo by John Kuehnert.

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Grand Canyon National Park and Grand Canyon-Parashant National Monument

Some of the lava erupted in the Uinkaret Volcanic Field between 75,000 and 725,000 years ago flowed down canyon walls to reach the Colorado River. The dams that blocked the Colorado River were short short lived dams, but today these lava cascades are some of the most dramatic scenery in the western Grand Canyon.

photo of a river canyon with steep rocky cliffs
One of the lava flows cascading into western Grand Canyon, Arizona

Photo by Allyson Mathis.

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Hawai’i Volcanoes National Park

Kīlauea and Mauna Loa are two of the most active volcanoes on Earth. As shield volcanoes, they are predominately made of lava flows. Kīlauea has had many historic periods of activity, including from 1983 to 2018, and a more recent eruption beginning in 2021. Mauna Loa’s most recent eruption was in 1984.

Aerial photo of molten lava flowing across a landscape
A channelized lava flow erupted from the Lower East Rift Zone in 2018. Hawaiʻi Volcanoes National Park, Hawai'i.

USGS photo.

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Isle Royale National Park

Isle Royale NP (and other parks in the Upper Midwest including Keweenaw National Historical Park, Voyageurs National Park, and Saint Croix National Scenic Riverway) contain voluminous basaltic lava flows that were erupted in the Midcontinent Rift approximately 1.1 billion years ago during pulling apart of the supercontinent Rodinia. More than 200 individual flows have been identified on the Keweenaw Peninsula where native copper was mined, predominately from mineralization in the flow tops. One of these lava flows, the Greenstone Flow is one of the largest lava flows recognized on Earth and has an aerial extent of more than 1,930 square miles (5,000 square km).

photo of the rocky shoreline of an island
Precambrian lava flows at Isle Royale National Park.

NPS photo.

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Katmai National Park

Katmai NP in southeastern Alaska is located on the Aleutian Peninsula, which is the most volcanologically active area in North America. Fourteen volcanoes in the park have experienced historic or prehistoric activity. Many of these volcanoes are composite cones which are composed of lava flows, and pyroclastic and lahar deposits.

Trident Volcano erupted from 1953-1974 and emitted a series of block lava flows. These andesitic flows are each about 1.5-2.5 mi (2.5-4 km) long and 80-200 ft (25-60 m) thick.

photo of a mountainous landscape with dark lava flows on the slopes
Dark-colored lava flows erupted between 1953 and 1960 during Trident’s eruption. Katmai
National Park & Preserve, Alaska.

USGS AVO photo by Cyrus Read.

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Lassen Volcanic National Park

Lassen Volcanic National Park has experienced a great variety of volcanic activity in the last few million years, with numerous lava flows and lava domes erupted.

Photo of a large lava flow
The Fantastic Lava Beds, a block lava flow, as viewed from Cinder Cone in Lassen Volcanic National Park. The Fantastic Lava Beds were erupted from a vent at the base of Cinder Cone near the end of its eruption in 1666 CE (Common Era).

NPS photo.

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Mount Rainier National Park

Mount Rainier is a large composite volcano made primarily of andesitic lava flows as well as lahar deposits.

photo of a cliff of layered rocks
Andesite lava flows near the summit of Mount Rainier.

USGS photo by Tom Sisson.

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Sunset Crater Volcano National Monument

The Bonita lava flow was erupted near the end of the Sunset Crater Volcano eruption in 1085 CE. It shows both pāhoehoe and ʻa‘ā forms, but is primarily ʻa‘ā.

photo of a rubbly slope of lava rock
Slabby ʻa‘ā in the Bonito Lava Flow.

Photo by John St. James on Flickr.

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Yellowstone National Park

Volcanic activity has occurred in the Yellowstone region during the last 50 million years. The largest eruptions were the three caldera-forming ones between 2,100,000 and 640,000 years ago. Large-volume rhyolite lava flows were erupted in Yellowstone following the most recent caldera-forming super-eruption, mostly between 160,000 and 70,000 years ago.

photo of a steep rocky cliff with columnar jointing
Obsidian Cliff in Yellowstone National Park is made of a 59,000 year old rhyolitic lava flow. This site was quarried for obsidian (volcanic glass) for 11,000 years and was designated as a National Historic Landmark by the NPS in 1996.

Photo by J. Schmidt.

National Parks Containing Lava Flows

Last updated: April 18, 2023