Lava fountaining

Definition

Lava fountaining is a volcanic activity characterized by the explosive ejection of molten rock (lava) into the air, forming spectacular jets and fountains. This phenomenon is primarily associated with basaltic magma, which has low viscosity, allowing gases to escape easily and create vigorous eruptions. Lava fountaining can significantly shape volcanic landforms and contribute to the formation of cinder cones and spatter cones.

5 Must Know Facts For Your Next Test

1. Lava fountaining typically occurs when gas pressure builds up within the magma, leading to explosive eruptions that can shoot lava hundreds of meters into the air.
2. The height and intensity of lava fountaining can vary widely, depending on factors such as the volume of gas present in the magma and the eruption's duration.
3. Lava fountains are often observed in shield volcanoes, where basaltic lava eruptions produce large volumes of fluid lava that can flow over long distances.
4. Cinder cones commonly form around the vent of a lava fountain, accumulating volcanic material as it falls back to the ground after being ejected.
5. Spatter cones can also develop from lava fountaining, where blobs of lava are thrown out and then solidify upon landing to create a cone-shaped structure.

Review Questions

• How does lava fountaining contribute to the formation of cinder cones?
  • Lava fountaining contributes to the formation of cinder cones by ejecting fragments of molten rock that accumulate around the vent during explosive eruptions. As lava is expelled high into the air, it cools and solidifies before falling back to the ground, creating a mound of volcanic debris. Over time, repeated fountaining events build up this material, resulting in the steep slopes characteristic of cinder cones.
• Discuss the relationship between magma viscosity and the intensity of lava fountaining during an eruption.
  • The intensity of lava fountaining is closely linked to the viscosity of the magma involved. Basaltic magma, which is low in viscosity, allows gases to escape easily, resulting in more vigorous eruptions and higher fountains. In contrast, more viscous magmas trap gases, leading to more explosive eruptions that can produce pyroclastic flows rather than sustained fountaining. This relationship highlights how magma composition affects volcanic behavior.
• Evaluate the ecological impacts of lava fountaining events on surrounding environments and their recovery processes.
  • Lava fountaining events can have significant ecological impacts on surrounding environments by altering landscapes and destroying habitats. The ejected lava can bury vegetation and soil, making recovery challenging. However, over time, ecosystems can regenerate as new soil forms from weathered volcanic material and species adapt to the altered landscape. This process may take decades or even centuries but ultimately contributes to biodiversity as new niches are created in the aftermath of such eruptions.

Related terms

Volcanic Ash: Tiny fragments of rock and glass created during explosive volcanic eruptions that can be carried by wind and affect air quality and aviation.

Magma Viscosity: A measure of a magma's resistance to flow, influenced by its temperature, composition, and gas content, affecting the style of volcanic eruptions.

Cinder Cone:

A type of volcano formed from the accumulation of volcanic debris, primarily composed of ash and small fragments of lava ejected during explosive eruptions.