CENAPRED reported that low-intensity exhalations occurred during most of the week. At 1118 on 30 December an intense seismic signal was recorded for 4 minutes that was characteristic of exhalations with explosive initial phases. At 1955 on 30 December a pilot report stated that an eruption sent an ash cloud to 8.5 km a.s.l. CENAPRED received reports that ash fell in the towns of Huejotzingo (~30 km to the NE of the volcano), San Pedro (~10 km to the SE), Cholula (~35 km to the E) and Puebla (~50 km to the E). GOES-8 imagery showed that ash from the eruption dissipated by 0100 on 31 December. Exhalations also occurred at 0507 on 31 December and at 0936 on 2 January, and sent ash clouds to 8.5 and 7.6 km, respectively.

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.

Sources: Washington Volcanic Ash Advisory Center (VAAC), Centro Nacional de Prevencion de Desastres (CENAPRED), Associated Press, Reuters