MEXICO CITY — Popocatépetl, the active volcano that rises some 40 miles southeast of the Mexican capital, exploded Monday night, sending a plume of ash and gas more than two miles into the inky sky and raining glowing rocks onto its slopes.

Video released by Mexico’s national disaster prevention agency showed a fiery light at the volcano’s crater at 9:38 p.m. The explosion was quickly enveloped in ash and pulverized rock as burning fragments of the volcano’s dome fell over a radius of a mile and a half.

Popocatépetl, whose name means “smoking mountain” in Nahuatl, the language of the Aztecs, sprang back to life in 1994 after a half-century of quiescence. Since then, the residents of the surrounding towns have grown accustomed to frequent emissions of gas and ash and periodic eruptions.

Over the past few weeks, the volcano has become more active, prompting the authorities to repeat warnings to keep a distance of about seven miles away from the summit.