Volcanic Gas Magma is molten rock containing dissolved gases that are released to the atmosphere during an eruption and while the magma lies close to the surface from hydrothermal systems. The gases are transported away from vents as acid aerosols, as compounds adsorbed on tephra and as microscopic salt particles. Sulfur compounds, chlorine and fluorine react with water to form poisonous acids damaging to the eyes, skin and repiratory systems of animals even in very small concentrations. The acids can destroy vegetation, fabrics and metals. Atmospheric veils of dust or acid aerosols caused by large-volume explosive eruptions can effect regional or global climate.
Most volcanic gases are noxious and smell bad, but they can cause mass fatalities.
An rare case of mass deaths by volcanic gases in 1986 at Lake Nyos, in Cameroon, West Africa. Tons of carbon dioxide spilled out of Lake Nyos, and flowed silently down a canyon and through 3 village occupied by 1700 people. They and 3000 cattle died instantly from lack of oxygen. Carbon dioxide emissions are now being monitored at Mammoth Mountain, California. Tsunamis A tsunami is a long-period sea wave or wave train generated by a sudden displacement of water.