A'a lava

Definition

A'a lava is a type of basaltic lava flow characterized by its rough, jagged surface formed from the cooling and solidification of lava as it moves down a slope. This type of lava is typically more viscous than pahoehoe lava, which results in its blocky appearance and sharp edges. A'a lava flows are significant in understanding volcanic landforms and products, as they can create diverse landscapes and contribute to the formation of volcanic features such as lava tubes and ridges.

5 Must Know Facts For Your Next Test

1. A'a lava flows typically occur at higher temperatures and lower gas content compared to other types of lava, making them more viscous.
2. The rough texture of a'a lava can create hazardous conditions for movement, as its sharp edges can be dangerous for people and animals.
3. A'a flows can travel at slower speeds compared to pahoehoe flows due to their higher viscosity, leading to different rates of landscape alteration.
4. A'a lava can form large clumps or blocks that pile up as they cool, contributing to the rugged terrain seen in areas with active volcanic activity.
5. The study of a'a lava is important for understanding volcanic eruptions and assessing potential hazards in regions prone to volcanic activity.

Review Questions

• How does the viscosity of a'a lava influence its movement and the formation of volcanic landforms?
  • The viscosity of a'a lava affects its movement by causing it to flow more slowly and create a rough, blocky surface as it cools. This high viscosity results in the formation of rugged terrains, such as steep slopes and piles of jagged blocks, which contrast with smoother pahoehoe flows. The way a'a lava spreads can lead to unique landforms like lava ridges and cooling structures, impacting the surrounding environment significantly.
• Compare and contrast a'a lava with pahoehoe lava in terms of their physical characteristics and how they contribute to volcanic landscapes.
  • A'a lava is characterized by its rough, jagged surface due to higher viscosity, while pahoehoe has a smooth, ropy texture caused by lower viscosity. These differences lead to varied contributions to volcanic landscapes: a'a flows tend to create steep, broken terrains, while pahoehoe forms gentle slopes and expansive fields. Understanding these characteristics helps geologists assess past volcanic activity and predict future eruptions based on the types of lava present.
• Evaluate the impact of a'a lava flows on human activities and safety in regions prone to volcanic eruptions.
  • A'a lava flows pose significant challenges for human activities due to their slow movement and hazardous surfaces that can injure individuals or disrupt transportation routes. The sharp edges and blocky nature of a'a lava make these areas dangerous for construction and outdoor activities. Awareness of these risks is crucial for emergency management and urban planning in volcanic regions, allowing communities to better prepare for potential eruptions and minimize damage.

Related terms

Pahoehoe: A type of basaltic lava flow known for its smooth, ropy surface, formed from less viscous lava that flows more easily compared to a'a lava.

Basalt: A dark, fine-grained volcanic rock that is commonly formed from the rapid cooling of basaltic lava at or near the Earth's surface.

Lava tube: A natural conduit through which lava travels beneath the surface of a lava flow, often created by the outer layer of lava cooling while the hotter interior continues to flow.