The way Mt Vesuvius erupted in 79 AD was the more dangerous of the two ways a composite volcano can erupt. The Mt Vesuvius eruption of 79 AD was a Plinian Eruption, named after the Pliny the Elder who was the uncle of Pliny the Younger, the person who first chronicled the entombment of Pompeii. The eruption of Mt Vesuvius in 79 AD came in two phases. Firstly, a Plinian eruption that lasted 20 hours churning out ash and pumice that reached depths of 2.8 metres at Pompeii. This was then followed by two pyroclastic flows which engulfed Pompeii, burning and asphyxiating the stragglers who had remained behind. Oplontis and Herculaneum were affected the most by the flows and were buried in fine ash and pyroclastic deposits.