The Centro Nacional de Prevención de Desastres (CENAPRED) reported that eruptive activity continued at Popocatépetl during 29 April-4 May. The seismic network recorded 11-35 long-period events per day, accompanied by steam-and-gas emissions; ash was detected in the emissions during 29-30 April. In addition, the seismic network recorded daily periods of tremor, sometimes characterized by harmonic and high-frequency signals, lasting from 34 minutes to three hours and 52 minutes. According to the Washington VAAC an ash plume was visible in webcam and satellite images on 10 April rising 5.8 km (20,000 ft) a.s.l. (about 400 m above the crater rim) and drifting SW. An event at around 0100 on 5 May ejected material onto the upper flanks and produced an ash plume that rose 6.4 km (21,000 ft) a.s.l. (as high as 1 km above the crater rim) and drifted E and ESE. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale) and the public was warned to stay 12 km away from the crater.

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)