Popocatepetl is a stratovolcano located in Central Mexico. It is the second largest volcano on the North American continent. After being dormant for 50 years, Popocatepetl became active in 1994.
Stratovolcanoes, also known as composite cones, rise from the landscape gently at the base and become steeper near the summit. Most stratovolcanoes form at plate boundaries. Many, including Popocatepetl, are found in what is known as the Ring of Fire, a series of volcanoes rimming the Pacific plate created from subduction of the plate boundaries. Eruptions of stratovolcanoes are associated with deadly pyroclastic flows. Hot volcanic fragments and toxic gases advance down slopes with little advance warning. Several hundred years generally occur between eruptions.
Popocatepetl is the Aztec word for smoking mountain. Topped by a 250- to 450-meter deep crater, remnants of an earlier predecessor are visible on the northwest slope. Areas south of the volcano are covered by the debris from at least three previous volcanoes active during the Pleistocene Era. As of June 2014, Popocatepetl has erupted 15 times since the arrival of the Spaniards in 1519, making it one of the most active volcanoes in Mexico. It endangers more than 20 million people living in the surrounding area.