Can a towns water supply become contaminated when a volcano is restless?
Yes, but probably not as quickly as shown in the movie. If a town’s water supply originates directly from a volcano’s groundwater system or from a stream that has been covered with volcanic ash, the water could become contaminated with foul-smelling gases or fine ash and other sediment. Some volcanic gases such as sulfur dioxide dissolve in groundwater, making the water acidic. Sulfurous odors, however, are caused by hydrogen sulfide gas, which smells like rotten eggs.