lava flow

References

Images & Videos

Lost Jim Lava Flow, southeastern Bering Land Bridge National Preserve, western Alaska, U.S.

Lava flow with black crust and some areas of visible orange glow. Black areas look ropy or like bunched fabric.

Study how magma erupts as lava and turns into pumice or hardens to form a shield volcano

The stages of lava: From eruption to cooling

Observe how Pahoehoe and aa lava flows over the Hawaiian vegetation and into the ocean

Magma streaming down a volcano.

lava flow

geology

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July 23, 2026

Quick Summary

Lost Jim Lava Flow, southeastern Bering Land Bridge National Preserve, western Alaska, U.S.

Lava is molten rock, or magma, that emerges onto Earth's surface. Temperatures of lava range from 700 to 1,200 °C (1,300 to 2,200 °F). Lava flows can be very fluid, like syrup, or quite stiff, with higher silica content leading to greater viscosity.1

Two main types of mafic lava flows are known by their Hawaiian names: pahoehoe and aa. Pahoehoe flows have smooth, ropy surfaces, while aa flows are rough and covered in jagged fragments. Pillow lava, named for its rounded masses, forms underwater. Intermediate and siliceous lavas form block lava flows, which are more fragmental.12

It is important to distinguish lava flows from pyroclastic flows, which are fast-moving, fluidized mixtures of hot volcanic fragments and gas, and are far more dangerous.13

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volcano
Lava flows
The root zone of volcanoes is found some 70 to 200 km (40 to 120 miles) below the surface of Earth. There, in Earth’s upper mantle, temperatures are high enough to melt rock and form magma. At these depths, magma is generally less…
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The root zone of volcanoes is found some 70 to 200 km (40 to 120 miles) below the surface of Earth. There, in Earth’s upper mantle, temperatures are high enough to melt rock and form magma. At these depths, magma is generally less…
Read More

igneous rock
…in two forms: (1) as lava flows that flood the land surface much like a river and (2) as fragmented pieces of magma of various sizes (pyroclastic materials), which often are blown through the atmosphere and blanket Earth’s surface upon settling. The coarser pyroclastic materials accumulate around the erupting volcano,…
Read More
…in two forms: (1) as lava flows that flood the land surface much like a river and (2) as fragmented pieces of magma of various sizes (pyroclastic materials), which often are blown through the atmosphere and blanket Earth’s surface upon settling. The coarser pyroclastic materials accumulate around the erupting volcano,…
Read More

lava
…the cooling of a molten lava flow. The temperatures of molten lava range from about 700 to 1,200 °C (1,300 to 2,200 °F). The material can be very fluid, flowing almost like syrup, or it can be extremely stiff, scarcely flowing at all. The higher the lava’s silica content, the…
Read More
…the cooling of a molten lava flow. The temperatures of molten lava range from about 700 to 1,200 °C (1,300 to 2,200 °F). The material can be very fluid, flowing almost like syrup, or it can be extremely stiff, scarcely flowing at all. The higher the lava’s silica content, the…
Read More

volcano
Mauna Loa, Hawaii, 1984
…24 hours the river of lava flowed 12 km (7.5 miles) northeast toward the city of Hilo. The vents erupted steadily for the next 10 days. Even though the eruption rate remained high, the advance of the front of the lava flow slowed, traveling 6 km (3.7 miles) on the…
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…24 hours the river of lava flowed 12 km (7.5 miles) northeast toward the city of Hilo. The vents erupted steadily for the next 10 days. Even though the eruption rate remained high, the advance of the front of the lava flow slowed, traveling 6 km (3.7 miles) on the…
Read More

pyroclastic flow
…to pyroclastic flows as “lava flows.” Moving lava flows are composed of viscous molten rock. Unlike pyroclastic flows, lava flows move slowly and, on cooling, harden into solid rock.
Read More
…to pyroclastic flows as “lava flows.” Moving lava flows are composed of viscous molten rock. Unlike pyroclastic flows, lava flows move slowly and, on cooling, harden into solid rock.
Read More