Lake Nyos, Cameroon

Question 1

Description and features

Answer 1

• One of a number of deep lakes that occupy volcanic craters in Cameroon in West Agra
• 2km wide and 200m deep

Question 2

What happened in August 1986?

Answer 2

• 1700 people and all animal life in the area around the volcano were asphyxiated
• Cause was a leak of CO2 from a volcanic crater lake, the gas had built up at the bottom of the lake after being emitted from the underlying magma chamber
• CO2 is a dense gas and when it escaped it flowed down the volcano slopes as a 50m thick ground-hugging layer traveling at about 70km/hour

Question 3

Possible explanations

Answer 3

• Not known for certain what caused the CO2 to escape the lack
• Could have been a deep movement of magma, an earthquake, a change in water temperature in the lake or strong winds stirring up the lake waters