Shield volcanoes

La Cumbre volcano

One of the two most important types of volcanoes, shield volcanoes are large and broad and have relatively gentle slopes. Kilauea on the island of Hawaii is good example of a shield volcano.

Eruptions on shield volcanoes are far less explosive than those on composite volcanoes. That is because the basalt lava that erupts from shield volcanoes contains less silica, SiO2, and is therefore less sticky (less viscous) and doesn't "plug up" the volcano. Because the lava is runnier, it travels further from the crater before it cools, causing the shield-like shape of the volcano as many eruptions build up over time.

Olympus Mons on Mars, another famous shield volcano, is much larger than any volcano on the Earth.

Image: The summit of La Cumbre, a shield volcano on Fernandina Island, Galapagos Islands, as seen from Earth orbit (credit: NASA/SPL)


La Cumbre volcano Shield volcanoes

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Shield volcanoes

A shield volcano is a type of volcano usually built almost entirely of fluid lava flows. They are named for their low profile, resembling a warrior's shield lying on the ground. This is caused by the highly fluid lava they erupt, which travels farther than lava erupted from stratovolcanoes. This results in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form. The shape of shield volcanoes is due to the low viscosity of their mafic lava.

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