Located about 70 kilometers (40 miles) southeast of Mexico City, Popocatépetl (pronounced poh-poh-kah-TEH-peh-til) is one of Mexico’s most active volcanoes. The towering stratovolcano has been erupting since January 2005, with near constant venting from fumaroles, punctuated by minor steam, gas, and ash emissions.
Activity began to intensify in mid-April 2012. The image above, captured by the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite, captured this view of Popocatépetl at 11:35 p.m. local time (16:35 Universal Time) on April 25, 2012.
A plume of steam and ash blows south from the volcano’s main vent. The ongoing eruption has flung hot rock fragments onto the northeast flank of the mountain, and a tan patch of what is probably new material—tephra—is visible just north of the main vent. Older lava flows are visible cutting into forests on the western slope. A portion of a cloud northwest of the main vent obscures part of the plume.
Popocatépetl, which means “smoking mountain” in the Aztec language, has seen low to moderate levels of activity throughout the past week. Other plumes similar to the one shown above have wafted from the volcano; an especially dense ash plume emerged on April 20th and drifted east at an altitude of 1.5 kilometers (0.9 miles). On April 18 and April 23, explosions sent hot, glowing rock fragments as far as 800 meters (874 yards) from the main vent; some of these fragments produced small mudslides, known as lahars.
On April 25, 2012, Mexico’s National Center for Disaster Prevention (CENAPRED) reported that Popocatépetl released bursts of steam, gas, and ash into the atmosphere at 1:00 p.m. and 5:26 p.m. local time; more than 13 low intensity “exhalations” of steam and gas occurred on the 26th, but only three contained ash.
Popocatépetl is situated between two large population centers: Mexico City (19 million) and Puebla (2.6 million). The region’s dense population means a serious eruption could have grave consequences. At a recent press conference, CENAPRED Director Roberto Quaas said scientists have no way of predicting whether the molten rock in the chamber will be slowly released or if it will erupt in a powerful explosion.