SYLLABUS: GENERAL STUDIES PAPER 1 (GEOGRAPHY)
Seismologists in the Democratic Republic of Congo (DRC) were still reporting earthquakes around the Mount Nyiragongo volcano a week after it erupted.
About Mount Nyiragongo
- It is an active volcano in the Virunga Mountains of east-central Africa.
- The Virunga Mountains are associated with the Albertine Rift.
- It lies in the volcano region of Virunga National Park, Congo (Kinshasa), near the border with Rwanda, 12 miles (19 km) north of Goma.
- Mount Nyiragongo is part of the Virunga volcanic chain and owes its existence to the activity of the African Great Rift.
- The rift is constantly extending and opening.
About Volcano Eruption
- A volcano can be active, dormant, or extinct.
- Mechanism of the volcanism:
- An eruption takes place when magma (a thick flowing substance), formed when the earth’s mantle melts, rises to the surface.
- Because magma is lighter than solid rock,it is able to rise through vents and fissures on the surface of the earth. After it has erupted, it is called lava.
Explosivity of volcanoes:
- Not all volcanic eruptions are explosive, since explosivity depends on the composition of the magma.
- When the magma is runny and thin, gases can easily escape it, in which case, the magma will flow out towards the surface.
- However, if the magma is thick and dense, gases cannot escape it, which builds up pressure inside until the gases escape in a violent explosion.
Threats due to volcanoes
- The most common cause of death from a volcano is suffocation, making people with respiratory conditions such as asthma and other chronic lung diseases more susceptible.
- People living in areas close to the volcano, or in low-lying areas downwind, are also at higher risk in case of an explosion since the ash may be gritty and abrasive and small ash particles can scratch the surface of the eyes.
- Also, volcanic eruptions can result in additional threats to health such as floods, mudslides, power outages, drinking water contamination and wildfires.
Dangers with rifting
- Other dangers associated with rifting, and volcano activity in the region, are:
- extreme fluidity of lava
- The earthquakes accompanying rifting episodes, which can themselves, cause significant damage.
- explosions when the hot lava reaches Lake Kivu waters causing its sudden boiling;
- the release of carbon-rich gases,particularly methane, during rifting and eruption, leading to explosions;
- The potential for carbon-rich gas accumulation at the bottom of Lake Kivu, which may cause surface water to sink, releasing lethal gases threatening Goma.
- Lake Kivuis one of the African Great Lakes.
- It lies on the border between the Democratic Republic of the Congo and Rwanda, and is in the Albertine Rift, the western branch of the East African Rift. Lake Kivu empties into the Ruzizi River,which flows southwards into Lake Tanganyika.