Strombolian eruption

Definition

A strombolian eruption is characterized by moderate explosive activity that results in the ejection of volcanic material, typically including small blobs of lava, ash, and gas, into the air at intervals. These eruptions often create a distinct rhythmic pattern and are primarily associated with basaltic magma, which allows for the formation of cinder cones and spatter cones as well as influencing the flow behavior of lava.

5 Must Know Facts For Your Next Test

1. Strombolian eruptions occur when gas bubbles in the magma rise and burst, causing small explosions that propel lava fragments into the air.
2. These eruptions are typically characterized by the gentle emission of lava that can flow relatively easily compared to more explosive eruption styles.
3. Strombolian eruptions can create prominent landforms like cinder cones due to the accumulation of ejecta around the vent over time.
4. The frequency and intensity of strombolian eruptions can vary significantly based on changes in magma supply and gas content within the volcanic system.
5. One of the most famous strombolian volcanoes is Stromboli itself, located in Italy, which has been erupting continuously for centuries and is often referred to as the 'Lighthouse of the Mediterranean.'

Review Questions

• What factors contribute to the characteristic explosiveness of strombolian eruptions compared to other eruption types?
  • Strombolian eruptions are influenced by the low viscosity of basaltic magma, which allows gas bubbles to rise relatively easily. The gas content within the magma is crucial; when these bubbles reach a critical size and burst, they create moderate explosions that eject lava fragments. This contrasts with more explosive eruption types where higher viscosity or different magma compositions can trap gas longer, leading to more violent eruptions.
• How do strombolian eruptions contribute to the formation and evolution of cinder cones?
  • Strombolian eruptions play a significant role in building cinder cones due to their rhythmic ejection of lava fragments that accumulate around the vent. As each explosion sends material into the air, it falls back to Earth, creating a steep-sided cone-shaped hill. Over time, repeated eruptions build up this structure as more layers of volcanic debris are added, making cinder cones a common feature associated with these types of eruptions.
• Evaluate the role of volcanic gas in determining the behavior and style of strombolian eruptions compared to other eruption styles.
  • Volcanic gas is a key factor in determining eruption behavior across various styles. In strombolian eruptions, a balance exists where sufficient gas pressure builds up without leading to catastrophic failure. This moderate pressure allows for periodic explosions that produce characteristic lava fountains. In contrast, other styles like Plinian eruptions have much higher gas content leading to explosive fragmentation due to rapid decompression. Thus, understanding gas dynamics not only helps predict strombolian activity but also contrasts it against more explosive eruption types.

Related terms

Basalt:

A dark, fine-grained volcanic rock that is typically rich in iron and magnesium, commonly associated with effusive eruptions and is the primary type of magma involved in strombolian eruptions.

Cinder Cone:

A type of steep, conical hill formed by the accumulation of volcanic debris such as ash and small rocks ejected during explosive eruptions, commonly found at strombolian eruption sites.

Volcanic Gas: Gases emitted from a volcano, including water vapor, carbon dioxide, and sulfur dioxide, which play a crucial role in the dynamics of eruptions and can influence the explosiveness of volcanic activity.