Phenomenon at Lake Kivu happens when CO2 from volcanic activity leaks through cracks in the ground
The Swahili word mazuku means roughly “evil wind” and refers to a lethal phenomenon around Lake Kivu on the border between the Democratic Republic of the Congo and Rwanda.
Carbon dioxide from volcanic activity leaks from cracks in the ground. The gas is heavier than air and collects in hollows, cellars, and low-lying areas, forming invisible and sometimes deadly pools, especially on windless nights. High concentrations of CO2 produce dizziness, nausea, confusion and weakness. Unwary victims who do not leave immediately tend to collapse then die in the high concentration of gas close to the ground.