stratovolcano

Also known as a composite volcano, a stratovolcano is a mountain made of layers, or strata, of pyroclastic material and lava flows. Widely considered to be the most dangerous type of volcano, they’re common along subduction zones in the earth’s crust, where plumes of molten rock rise into the magma chamber, eventually leading to an eruption. One one side of the eruptive spectrum (otherwise known as the Volcanic Explosivity Index, or VEI) are Strombolian eruptions. Named after the Italian stratovolcano Stromboli, these gas-driven explosions propel small lava fountains into the air, lasting only a few seconds each. On the opposite side of the VEI are Plinian eruptions. These eruptions are large and violent, unleashing pyroclastic flows, ash columns, lava bombs, pumice, and tephra upon anyone unlucky enough to be caught in one. On October 24, AD 79, Mount Vesuvius erupted with such force that the entire volcanic cone was destroyed by the next day. Vesuvius ejected an ash column several miles into the atmosphere, which was so heavy that it later collapsed on itself. Pyroclastic surges razed the towns of Pompeii, Herculaneum, and Stabiae to the ground. A witness of the eruption, Pliny the Younger, was responsible for the first and most detailed account of a volcanic eruption in recorded history. It seemed prudent that the type of eruption he described at Vesuvius should be named after him.