Anatomy of Nyiragongo

Vent
Vents are openings in the Earth's crust from which magma and volcanic gases escape onto the ground or into the atmosphere. Vents may consist of a single, circular-shaped structure, a large elongated fissure or fracture (as seen on the diagram above) or a tiny ground crack. Nyiragongo is notorious for releasing large amounts of sulfur dioxide through its many vents. At 54,000 tons or more each day, this is more than any other active volcano, and it presents a serious health hazard to people and animals living in close proximity.