Bursting a bubble?
Understanding the processes that cause volcanic eruptions can help scientists predict how often and how violently a volcano will erupt. Although scientists have a general idea of how these processes work — the melting of magma below the volcano causes liquid magma and gases to force their way to Earth’s surface — eruptions happen so rarely, and often with little warning, that it can be difficult to study them in detail. One volcano that volcanologists believe they understand fairly well is Italy’s Stromboli, which has been erupting every five to 20 minutes for thousands of years, spewing fountains of ash and magma several meters into the sky. For several decades, scientists have pretty much used one theory to explain what is causing huge amounts of gas to erupt so frequently: swimming-pool-sized bubbles that travel through a few hundred meters of molten magma before popping at the surface. But they may...