Definition of Volcanic Fissures in Geography: Examples and Formation

🌍 Quick Study Guide

• 🌋 Volcanic fissures are linear cracks or fractures in the Earth's crust through which lava erupts.
• 🔥 Unlike central vent volcanoes, fissures produce lava flows that can spread over large areas, creating flood basalts.
• 🧭 Fissure eruptions are commonly associated with areas undergoing crustal extension, such as rift valleys and mid-ocean ridges.
• ⏱️ Eruptions can be short-lived or persist for extended periods, depending on the magma supply and tectonic setting.
• 🗺️ Examples include the Laki fissure in Iceland and the East African Rift System.
• 🧪 The composition of lava erupted from fissures can vary from basaltic to rhyolitic, influencing the eruption style and landforms created.
• 📈 Monitoring fissure activity is crucial for assessing volcanic hazards and mitigating potential risks to nearby communities.

🌋 Practice Quiz

1. What is a volcanic fissure?
   1. A circular vent on a volcano
   2. A linear crack in the Earth's crust through which lava erupts
   3. A type of volcanic bomb
   4. A mountain formed by volcanic activity
2. Which geological feature is commonly associated with fissure eruptions?
   1. Subduction zones
   2. Transform faults
   3. Rift valleys
   4. Fold mountains
3. The Laki fissure is located in which country?
   1. Italy
   2. Iceland
   3. Hawaii
   4. Japan
4. What type of lava flow can fissure eruptions produce over large areas?
   1. Pahoehoe
   2. Aa
   3. Flood basalts
   4. Pillow lava
5. What tectonic setting is most conducive to fissure eruptions?
   1. Crustal compression
   2. Crustal extension
   3. Strike-slip movement
   4. Convergent boundaries
6. The composition of lava from fissures can vary from:
   1. Andesitic to dacitic
   2. Basaltic to rhyolitic
   3. Granitic to dioritic
   4. Peridotitic to komatiitic
7. Why is monitoring fissure activity important?
   1. To predict earthquakes
   2. To assess volcanic hazards
   3. To study the Earth's magnetic field
   4. To locate mineral deposits