Now, Williams is working with two companies to develop instruments that would allow him to collect critical gas-emissions data from an active volcano at a safe distance. Ill. Understanding the behavior of gases at a volcano could potentially lead to better eruption-forecasting techniques. The most dominant volcanic gases are water vapor, carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrofluoric acid. If you pull the cork out quickly, the champagne will explode as a big frothy, foamy eruption. The gases, mostly carbon dioxide that is dissolved in the champagne, are confined by the heavy, strong bottle and a cork.
Volcanic eruptions work in a similar fashion.
A magma body forms about a hundred miles beneath a volcano. Lighter than the surrounding rocks, the magma begins to rise. The pressure that keeps the gases dissolved drops, allowing them to boil off. Carbon dioxide boils first, then sulfur dioxide. That's ideal, a wonderful thing for forecasting an eruption.