Syllabus:
GS1: Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc., geographical features and their location-changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.
Context:
Recently, Italy’s Mount Etna erupted explosively, sending a huge cloud of ash, smoke, and rock fragments several kilometres into the sky.
More on the News
- The eruption was accompanied by volcanic tremors, widely felt in nearby towns and villages.
- Despite the dramatic spectacle, there were no reported injuries or damages.
- Experts suggest that the eruption began with an increase in pressure inside the volcano due to expanding gases, which led to the collapse of the southeast crater, resulting in hot lava flows.
- According to Italy’s National Institute of Geophysics and Volcanology (INGV) Etna Observatory, the volcano was witnessing a “Strombolian” eruption.
Mount Etna
- Mount Etna is located on the east coast of Sicily, the largest island in the Mediterranean Sea.
- Etna is the highest peak in Italy south of the Alps.
- It is the largest active volcano in Europe.
- This mountain is designated a UNESCO World Heritage Site in 2013 due to its extensive eruptive history.
- Mount Etna is also known as the “Lady of the Rings” for its ability to emit rings of water vapour during eruptions.
Geological Features
- Etna has five summit craters, which are typically responsible for most eruptions.
- It also has around 300 flank vents of varying sizes on its slopes, which can also erupt.
- The volcano is in near-constant activity.
Eruption History of Mount Etna
Since 1600, Etna has witnessed:
- At least 60 flank eruptions
- Numerous summit eruptions
Recent summit eruptions occurred in:
- 2006, 2007–08, 2012 (twice), 2018, and 2021
Flank eruptions occurred in:
- 2001, 2002–03, 2004–05, and 2008–09
Etna’s activity is documented for at least 2,700 years, and can be traced back 500,000 years according to UNESCO.
Type of Eruption – Strombolian vs. Plinian
- Eruption types help classify volcanoes by explosiveness and potential danger.
- More explosive eruptions cover larger areas and pose higher risks due to speed and reach.
Strombolian Eruption
- It is characterised by moderately explosive bursts, ejecting rock and cinders.
- It is caused by gas buildup in the magma chamber.
- When the gas bubbles reach the surface, they can burst suddenly, throwing material skywards.
- It is named after Italy’s Stromboli volcano, which erupts every 10–20 minutes.
Possible Plinian Eruption
- Some volcanologists argue it was a Plinian eruption, not Strombolian.
- Plinian eruptions are highly explosive, launching gas, ash, and rock into the stratosphere.
- The height of the ash plume in this case suggests a more intense eruption.
UPSC PYQ:
Q. Mention the global occurrence of volcanic eruptions in 2021 and their impact on regional environment. (2021)
Mains Practice Question
Q. What are the geological features and eruptive characteristics of Mount Etna? Discuss how its recent activity reflects the nature of volcanic hazards in tectonically active zones.