‘Volcanic Ash’ Isn’t Actually Ash
“Every few months, a volcanic eruption occurs on Earth, with lava flows and enormous plumes of volcanic ash. These small eruptions might produce only ~0.01 cubic kilometers of ash, while large, rare ones can produce thousands. Unlike the result of combustion, however, what we call volcanic ash isn’t ash at all.”
When you burn something like wood, coal, oil, or gas, the ash you produce is whatever’s left after the combustion reaction, combining the fuel with oxygen in the presence of heat, is complete. That type of ash can easily be washed away and, although it has a number of reuses, is fairly easy to clean up. But volcanic ash is fundamentally different. Instead of a product of combustion, it’s made of very small, often microscopic particles of rock, glass, or minerals. It’s produced when magma or the gases trapped within it reach the atmosphere and rapidly expand. When ashfall occurs, the consequences are not only extraordinary, but the hazards and cleanup are extraordinarily different from when combustive ashfall occurs.