Fissure Eruption

Definition

A fissure eruption is a volcanic event where lava flows out from a linear fracture or crack in the Earth's surface rather than a central vent. These eruptions typically produce extensive lava fields and can lead to the formation of unique landforms, such as flood basalt plateaus. Fissure eruptions play a significant role in shaping volcanic landscapes and contribute to the diversity of volcanic products.

5 Must Know Facts For Your Next Test

1. Fissure eruptions are often characterized by relatively non-explosive outpourings of basaltic lava, creating wide expanses of land covered in lava flows.
2. These eruptions can last for days to years, contributing significantly to the volume of lava produced during a volcanic activity period.
3. The lava produced during fissure eruptions tends to have low viscosity, allowing it to flow easily over long distances, which can create vast plateaus.
4. Fissure eruptions are a common feature in hotspot volcanism, such as the Hawaiian Islands, where they create extensive lava fields.
5. The landscape created by fissure eruptions can include features like lava tubes and scoria cones, contributing to the diversity of volcanic landforms.

Review Questions

• How do fissure eruptions differ from traditional central vent eruptions in terms of lava production and landform creation?
  • Fissure eruptions differ from central vent eruptions primarily in their mode of lava release and resulting landforms. While central vent eruptions typically involve explosive activity that ejects ash and tephra, fissure eruptions release lava from cracks in the ground, leading to extensive flows. This results in unique landforms such as flood basalts rather than the steep-sided cones characteristic of central vent volcanoes. The difference in eruption style also influences the type and distribution of volcanic products created.
• Discuss the environmental impacts of fissure eruptions compared to explosive volcanic events.
  • Fissure eruptions generally have different environmental impacts than explosive volcanic events due to their lower explosivity and more extensive lava flows. While explosive eruptions can produce ash clouds that affect air quality and climate on a global scale, fissure eruptions tend to result in localized effects through the direct deposition of lava. However, large-scale fissure eruptions can still significantly alter landscapes, destroy habitats, and influence local ecosystems as they create new landforms and change drainage patterns.
• Evaluate the role of fissure eruptions in understanding volcanic processes and their contributions to Earth's geological history.
  • Fissure eruptions provide critical insights into volcanic processes and contribute significantly to Earth's geological history. By studying these events, geologists can learn about magma dynamics, the movement of tectonic plates, and how large volumes of basaltic lava interact with the environment. These eruptions help scientists understand the formation of extensive geological features like flood basalts and play a key role in reconstructing past volcanic activity and its effects on climate and biodiversity. Furthermore, they highlight the importance of non-explosive volcanic activity in shaping both landscapes and ecosystems.

Related terms

Lava Flow: The movement of molten rock (lava) that emerges from a volcano during an eruption, which can vary in viscosity and can travel varying distances.

Basalt:

A dark, fine-grained volcanic rock that forms from the rapid cooling of low-viscosity lava, commonly associated with fissure eruptions.

Shield Volcano:

A broad, gently sloping volcano formed by the eruption of low-viscosity basaltic lava, often associated with fissure eruptions and extensive lava flows.