Shield volcano

Definition

A shield volcano is a broad, domed volcano characterized by gentle slopes and primarily constructed by the eruption of low-viscosity basalt lava that can flow over great distances. This type of volcano is formed from repeated, non-explosive eruptions that build up layers of lava, leading to its unique shield-like shape. Shield volcanoes are significant because they offer insights into volcanic processes and can produce large amounts of lava with relatively low levels of explosiveness.

5 Must Know Facts For Your Next Test

1. Shield volcanoes typically have gentle slopes of less than 10 degrees due to their low-viscosity lava that spreads out in thin layers.
2. The largest shield volcano in the world is Mauna Loa in Hawaii, which covers an area of about 5,271 square kilometers (2,035 square miles).
3. Eruptions from shield volcanoes are generally less violent than those from stratovolcanoes, making them more predictable and safer for nearby communities.
4. Some shield volcanoes can create extensive lava plateaus as lava flows accumulate over time, significantly altering the landscape.
5. The eruptions from shield volcanoes can last for long periods, with some forming over thousands of years due to continuous lava outpouring.

Review Questions

• How do the characteristics of shield volcanoes differentiate them from other types of volcanoes?
  • Shield volcanoes are distinguished by their broad, gently sloping shapes and the type of lava they produce, which is low-viscosity basalt that flows easily over long distances. Unlike stratovolcanoes, which have steep profiles and are built from a combination of explosive eruptions and lava flows, shield volcanoes primarily form through non-explosive eruptions. This results in their characteristic shape and behavior, showcasing a different volcanic process that contributes to the diversity of volcanic landforms.
• Discuss the implications of shield volcano eruptions on surrounding ecosystems and communities compared to other volcanic types.
  • Eruptions from shield volcanoes generally pose less risk to surrounding ecosystems and communities due to their non-explosive nature. The predictable lava flows allow for better monitoring and evacuation plans compared to the sudden explosive eruptions associated with stratovolcanoes. However, while they may be less violent, large lava flows can still cover extensive areas, destroying habitats and altering landscapes significantly over time. Therefore, understanding shield volcanism is vital for assessing potential risks and impacts on human activities.
• Evaluate the role of shield volcanoes in understanding volcanic activity and their contribution to geological research.
  • Studying shield volcanoes provides crucial insights into volcanic processes because they exhibit consistent patterns of eruption and lava flow. Their long-term eruptions allow scientists to observe how lava interacts with the environment over time, informing models of magma movement and eruption forecasting. Moreover, because shield volcanoes often have well-preserved features due to their relatively gentle eruptions, they serve as natural laboratories for geological research. This contributes to a better understanding of not only volcanic activity but also broader Earth processes related to tectonics and landscape evolution.

Related terms

Basalt: A dark, fine-grained volcanic rock that is the primary material erupted from shield volcanoes, known for its low viscosity.

Lava flow: The movement of molten rock from a volcano, which can travel long distances, especially in the case of shield volcanoes.

Volcanic eruptions: The process by which magma from beneath the Earth's crust escapes to the surface, resulting in various forms of volcanic activity, including those seen in shield volcanoes.