Mount Etna, one of the most active volcanoes in the world, has a complex history of eruptions that have followed vastly different paths. Some magma from the volcano has lingered near the surface for weeks, while other magma has surged upward from depths of nearly 30 kilometers in just hours. A research team led by Esteban Gazel from Cornell University has uncovered how these differences are influenced by volcanic gases, such as carbon dioxide and water. This discovery could provide a new tool for predicting and understanding explosive eruptions. The findings were published in the journal Geochemistry, Geophysics, Geosystems and highlight the importance of studying the movement and composition of magma beneath the Earth's surface. The research team studied two major historical eruptions at Mount Etna in Italy. Using a technique called Raman spectroscopy, they examined tiny gas bubbles trapped in crystals that formed within the magma. These bubbles are as small as 1 to 10% the thickness of a human hair, but they contain valuable information about the pressure and depth of the magma at the time of the eruption. By analyzing these bubbles, the scientists were able to reconstruct the paths that magma took to reach the surface. In one case, magma rose from a depth of about 22 kilometers, moved slowly, and then stalled at a shallower depth of 2 to 5 kilometers, releasing gas over several weeks before erupting. In another, magma traveled rapidly from depths of 24 to 30 kilometers and erupted within just a few hours. The study revealed that the balance between carbon dioxide and water in the magma plays a crucial role in determining how an eruption unfolds. Higher levels of carbon dioxide can drive magma upward quickly from deep within the Earth, while water becomes more influential when magma remains at shallower depths for longer periods. This distinction helps explain why some eruptions are more explosive than others. Mount Etna is unique because it has both types of volatile gases, making it an ideal location to study their effects. The findings could improve models used to predict volcanic behavior and assess risks for future eruptions. The research team has already begun applying their method to other volcanoes, including those in Chile and Hawaii, with the goal of studying all major volcanoes worldwide. Understanding the movement of magma and the gases that drive it is essential for building more accurate models of volcanic activity. Mount Etna, with its long and varied eruption history, also has deep cultural significance. In Greek mythology, it was believed to be the burial site of the giants Typhon and Enceladus. Gazel, who led the research, finds a fascinating connection between these ancient myths and the underground structures revealed by his team’s work. The study not only advances scientific knowledge but also highlights the enduring relationship between volcanoes and human history.