Case study: volcanic eruption
Nyiragongo is a steep-sided, active volcano [active volcano: A volcano which erupts regularly.] . It is located in the Democratic Republic of Congo. Nyiragongo and the shield volcano [shield volcano: A volcano with gentle slopes that was made by runny, less explosive lava.] of Nyamuragira, 40 km away, are part of the East African Rift Valley [East African Rift Valley: A large scale fracture in the earth in East Africa.] . This is an area of many faults [fault: A fracture in the Earth's crust.] where the plates are being stretched as they move away from each other.
Cause of the eruption
The eruption happened on 17 January 2002. The volcano has a lava lake in its crater. Fissures [fissure: A crack in the land formed by tectonic activity such as earthquakes.] opened up to the south side of the volcano and three streams of lava from the lake drained through the fissures. The lava reached speeds of 60 km/h. There was little warning as the lava reached the city of Goma. The unrest in the country has made it difficult to monitor the volcano and put emergency responses in place.
Social impacts of the eruption (effects on people)
Homes were destroyed by ash and lava.
45 people died in the first 24 hours.
The lava flow made it difficult to travel around Goma as it filled the roads. Aid agencies were unable to access some areas of Goma.
The lava took a long time to cool and it burnt people as they tried to return to their homes.
Cholera [cholera: A disease spread via unclean water.] spread because of lack of sanitation [sanitation: Measures to help cleanliness and hygiene. ] in areas that people fled to.
Around 50 people were killed when fuel exploded while they were trying to siphon it off at a petrol station.
14 nearby villages were destroyed in the lava flow.
Economic impacts of the eruption (effects on money and jobs)
People returned to Goma hoping to find aid. One month after the eruption, 350,000 people were dependant on aid.
People lost their businesses and jobs.
Aviation fuel stores exploded as the lava flow damaged Goma airport.
Environmental impacts of the eruption
Lava covered 15 per cent of the city of Goma and destroyed 30 per cent of the city.
If the lava was to reach Lake Kivu, or seismic activity [seismic activity: Earthquakes that happen as a result of tectonic plate movements.] disrupted the lake, then dangerous gases of carbon dioxide and methane could be released from the floor of the lake.
Mount Nyiragongo is 3470m high and is an active stratovolcano in Eastern Democratic Republic of the Congo (an LDC). It is found on the Kivu part of the Albertine rift, the Western branch of the Great African rift valley. It is found 20 km north of the town of Goma and Lake Kivu and just west of the border with the country of Rwanda. Its crater is 2km wide and contains a lava lake.
The volcano has an extensive volcanic history, and has erupted at least 34 times since 1882. The volcano is active because it sits above the point where the African plate is moving apart. It is thought that a hot spot could be responsible for the great volcanic activity found Nyiragongo and nearby Nyamuragira.
The volcano has fluid eruptions of Basaltic lava. Lava flows at Nyiragongo have been known to move at up to 100 km/h because of the extremely low silica content. This is similar to the lava found at Hawaii but has resulted in a different volcanic shape.
The eruption of 2002
Date - January 17, 2002
Months of increased earthquake and steam/gas eruptions (fumaroles). This resulted in a 13 km fissure opening on the south flank of the volcano. Lava exited from 3 points on the fissure and moved in a stream 200 to 1000 m wide and up to 2 m deep through Goma. Warnings had been given and 400,000 people were evacuated from the city.
· Lava covered parts of the runway at Goma International Airport
· Lave also reached lake Kivu
· Scientists were worried about carbon dioxide and methane poisoning from the lake but it did not occur.
· Around 147 people died from suffocation by CO2 or buildings collapsing due to the lava and earthquakes
· Around 15% of Goma comprising 4,500 buildings were destroyed
· 120,000 people homeless.
· 400,000 people evacuated
· 2 of the city's four hospitals, three out of the 11 health centres and 80 out of Goma's 150 pharmacies were buried under two meters of lava.
Earthquakes followed the eruption and the volcano continues to be active.