This Christmas break my family decided to trek down to Pompeii to visit the ruins and Mount Vesuvius, something that I have wanted to do for a long time. If you’ve ever taken an introductory geology class, then you’ve probably heard the story of the eruption of Vesuvius in 79 AD, as it is used to illustrate several concepts about volcanic eruptions. The 79 AD eruption began with a Plinian eruption, where a large column of ash extends high into the air, as far as the stratosphere. The term “Plinian eruption” is derived directly from the 79 AD Vesuvius eruption – Pliny the Younger was one of the first people to describe a volcanic eruption in detail. There are many examples of Plinian eruptions from the last few decades – Mount Pinatubo in 1991, Mount St. Helens in 1980, and most recently, Eyjafjallajökull in 2010. After a day of Plinian-style eruption, several pyroclastic flows covered the cities of Pompeii, and, in particular, Herculaneum. Like many other volcanos, Mount Vesuvius is found at the intersection of two plate boundaries. The African Plate is subducting (diving down) beneath the Eurasian Plate, and as this occurs, melted rock moves up towards the surface and eventually erupts from the volcano. Continue reading →