CENAPRED reported that each day during 4-10 August there were 30-92 steam-and-gas emissions from Popocatépetl. The plumes drifted mainly W and some contained ash. A minor explosion was recorded at 0652 on 4 August. At 2137 on 6 August a moderately-sized explosion produced a plume, thought the height and drift direction were obscured by weather conditions. Incandescent fragments ejected from the crater were seen falling on the flanks not far from the crater rim. Weather conditions again prevented views of an explosion at 0258 on 8 August. The Alert Level remained at Yellow, Phase Two (middle level on a three-color scale).

Geological Summary. Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, rises 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 CE, have occurred since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since Pre-Columbian time.

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)