Context:
An active volcano in Congo, Mount Nyaragongo, erupted again.
The Indian Army contingent under the United Nations peace keeping mission (MONUSCO) assisted in protecting civilians and U.N. officials as well as assets during the evacuation.
Relevance:
GS-I: Geography (Physical geography, Volcanoes, Important Geophysical phenomena), GS-III: Disaster Management
Dimensions of the Article:
- Mount Nyiragongo
- Stratovolcano
- Albertine Rift
Mount Nyiragongo
- Mount Nyiragongo is an active stratovolcano in the Virunga Mountains associated with the Albertine Rift.
- It is located inside Virunga National Park, in the Democratic Republic of the Congo just west of the border with Rwanda.
- The crater presently has two distinct cooled lava benches within the crater walls and Nyiragongo’s lava lake has at times been the most voluminous known lava lake in recent history.
- Nyiragongo and nearby Nyamuragira are together responsible for 40 per cent of Africa’s historical volcanic eruptions.
- The volcano partly overlaps with two older volcanoes, Baratu and Shaheru, and is also surrounded by hundreds of small volcanic cinder cones from flank eruptions.
Stratovolcano
- A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra.
- Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas.
- The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity.
- The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma.
- Stratovolcanoes are sometimes called “composite volcanoes” because of their composite stratified structure built up from sequential outpourings of erupted materials.
- They are among the most common types of volcanoes, in contrast to the less common shield volcanoes.
- Two famous examples of stratovolcanoes are Krakatoa in Indonesia, known for its catastrophic eruption in 1883, and Vesuvius in Italy, whose catastrophic eruption in AD 79 buried the Roman cities of Pompeii and Herculaneum.
- In modern times, Mount St. Helens in Washington State, USA and Mount Pinatubo in the Philippines have erupted catastrophically, but with fewer deaths.
Albertine Rift
- The Albertine Rift is the western branch of the East African Rift, covering parts of Uganda, the Democratic Republic of the Congo (DRC), Rwanda, Burundi and Tanzania.
- It extends from the northern end of Lake Albert to the southern end of Lake Tanganyika. The geographical term includes the valley and the surrounding mountains.
- The Albertine Rift and the mountains are the result of tectonic movements that are gradually splitting the Somali Plate away from the rest of the African continent.
- The mountains surrounding the rift are composed of uplifted Pre-Cambrian basement rocks, overlaid in parts by recent volcanic rocks.
-Source: The Hindu
