Shield volcano

Definition

A shield volcano is a type of volcano characterized by its broad, gently sloping sides formed primarily from the eruption of low-viscosity basalt lava. These volcanoes typically produce large volumes of fluid lava flows that can travel great distances, resulting in their shield-like shape. They are commonly found at hotspots and divergent tectonic boundaries across the solar system.

5 Must Know Facts For Your Next Test

1. Shield volcanoes typically have a gentle slope of less than 10 degrees, which distinguishes them from more steeply sloped stratovolcanoes.
2. The largest volcano in the solar system is Olympus Mons on Mars, a shield volcano that reaches about 13.6 miles (22 kilometers) high and spans roughly 370 miles (600 kilometers) across.
3. Mauna Loa in Hawaii is one of the most studied shield volcanoes on Earth and is notable for its massive size and frequent eruptions.
4. Eruptions from shield volcanoes are usually non-explosive due to the low viscosity of basaltic lava, leading to lava flows rather than explosive ash clouds.
5. Other celestial bodies, like Io (one of Jupiter's moons), also exhibit features similar to shield volcanoes, showcasing volcanism beyond Earth.

Review Questions

• How does the shape and structure of a shield volcano relate to the types of eruptions it produces?
  • The shape and structure of a shield volcano are closely related to its eruptive style. The broad, gentle slopes result from the flow of low-viscosity basalt lava that can travel far from the eruption site before cooling. This contrasts with steeper volcanoes, where thicker lava tends to build up around the vent due to explosive eruptions. Thus, the unique shape of shield volcanoes reflects their tendency for non-explosive eruptions that create extensive lava flows rather than ash clouds.
• Discuss how shield volcanoes contribute to our understanding of volcanic activity on other celestial bodies in the solar system.
  • Studying shield volcanoes on Earth enhances our understanding of similar geological processes on other celestial bodies like Mars and Io. For instance, features resembling shield volcanoes on Mars suggest that ancient volcanic activity may have occurred under conditions similar to those on Earth. By comparing these extraterrestrial formations with Earth's shield volcanoes, scientists can infer past volcanic behaviors and tectonic movements, helping us understand the geological history and evolution of other planets.
• Evaluate the implications of studying shield volcanoes on Earth for predicting volcanic activity on planets like Mars or moons like Io.
  • Studying shield volcanoes on Earth provides valuable insights into predicting volcanic activity on other planets such as Mars or moons like Io by identifying patterns in eruption styles and lava flow dynamics. By understanding how these volcanoes behave under different conditions, scientists can develop models that estimate potential eruption risks and volcanic landscapes elsewhere in the solar system. Additionally, these models assist in interpreting geological features observed by missions exploring these celestial bodies, contributing to our broader understanding of planetary geology and volcanism.

Related terms

Basalt: A dark, fine-grained volcanic rock that forms from the rapid cooling of low-viscosity lava, which is the primary material erupted by shield volcanoes.

Hotspot: An area in the mantle where a plume of hot material rises, creating volcanic activity independent of tectonic plate boundaries, often leading to the formation of shield volcanoes.

Lava flow: The movement of molten rock (lava) from a volcano, which can vary in speed and distance depending on the viscosity and composition of the lava.