Shield volcano

Definition

A shield volcano is a broad, dome-shaped volcano characterized by gentle slopes and primarily built up by the flow of low-viscosity basaltic lava. These volcanoes are typically formed by frequent, non-explosive eruptions that produce lava flows that can travel over long distances, creating a shield-like appearance when viewed from above. Their eruptions tend to be less hazardous than those of other types of volcanoes, but they can still pose risks to nearby areas through lava flows and gas emissions.

5 Must Know Facts For Your Next Test

1. Shield volcanoes are primarily composed of basalt lava, which is low in viscosity and allows for the formation of wide, gently sloping structures.
2. These volcanoes usually erupt non-explosively, resulting in relatively predictable lava flows that can cover large areas.
3. Although shield volcanoes are generally less dangerous than stratovolcanoes or composite volcanoes, they can still produce significant hazards such as lava flows, which can destroy property and alter landscapes.
4. Famous examples of shield volcanoes include Mauna Loa and Kilauea in Hawaii, both of which have frequent eruptions that contribute to their large size.
5. Monitoring shield volcanoes involves tracking seismic activity, gas emissions, and ground deformation to anticipate potential eruptions and assess their impacts.

Review Questions

• How do shield volcanoes differ from other types of volcanoes in terms of eruption style and physical structure?
  • Shield volcanoes differ from other types such as stratovolcanoes due to their low-viscosity basalt lava that results in gentle slopes and broad bases. While stratovolcanoes tend to have steep profiles and explosive eruptions, shield volcanoes erupt more frequently but less violently. This creates wide, dome-shaped structures with extensive lava flows rather than explosive ash clouds.
• What role does basalt lava play in the formation and eruption dynamics of shield volcanoes?
  • Basalt lava is crucial to the formation and eruption dynamics of shield volcanoes because it has a low viscosity that allows it to flow easily over long distances. This characteristic contributes to the gentle slopes typical of shield volcanism. As the lava spreads out in thin layers during eruptions, it builds up the broad profile of the volcano while minimizing explosive activity.
• Evaluate the potential hazards associated with shield volcano eruptions and how monitoring techniques can mitigate these risks.
  • The potential hazards associated with shield volcano eruptions primarily include destructive lava flows and gas emissions. Although these eruptions are often non-explosive, they can still lead to significant damage to infrastructure and ecosystems if not anticipated. Monitoring techniques such as seismology, gas emission analysis, and satellite imaging play an essential role in hazard assessment by providing data on volcanic activity, helping to inform communities about evacuation plans and risk management strategies.

Related terms

Basalt: A type of dark, fine-grained volcanic rock that is the primary material erupted from shield volcanoes.

Lava flow: The movement of molten rock (lava) that flows out of a volcano during an eruption, which is a key feature in the formation of shield volcanoes.

Mauna Loa: One of the largest shield volcanoes in the world, located in Hawaii, known for its extensive lava flows and gentle slopes.