CENAPRED reported that there were 39-108 steam-and-gas emissions, sometimes containing minor amounts of ash, rising from Popocatépetl each day during 9-15 November. Weather clouds often prevented visual observations of activity. The seismic network recorded daily periods of tremor lasting from 33 minutes to 302 minutes. According to the Washington VAAC, daily ash plumes rose to 5.8-7.6 km altitude (19,000-25,000 ft) and drifted SW, S, SE, and E. Four minor explosions were detected at 1337, 1625, 1629, and 2026 on 10 November. Another four minor explosions were detected at 0141, 1109, 1223, and 1519 on 11 November. Three minor explosions were recorded at 0919, 1933, and 2057 on 12 November. Three minor explosions were detected at 1302 on 13 November, and four minor explosions at 0131, 0615, 1459, and 2330 on 14 November. A minor explosion was also detected at 0710 on 15 November. A total of five volcano-tectonic earthquakes were recorded on 11 and 12 November. Light ashfall was reported in Tochimilco, Puebla on 10 November. The Alert Level remained at Yellow, Phase Two (the 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.

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