Centro Nacional de Prevención de Desastres (CENAPRED) reported that eruptive activity continued at Popocatépetl during 23-29 October. The seismic network recorded 16-50 long-period events per day that were accompanied by steam-and-gas emissions sometimes containing minor amounts of ash. The seismic network also recorded daily tremor, characterized at high-frequency and low-to-moderate amplitude, with periods lasting 14 hours and 20 minutes to as long as almost 24 hours.

According to the Washington VAAC ash plumes visible in webcam and satellite images during 22-25 October rising 5.5-7.3 km (18,000-24,000 ft) a.s.l. and drifting as far as 190 km N, NW, and NNW and 400 km N and NE, extending beyond the coastline. Overnight during 24-26 October webcams recorded the ejection of incandescent fragments short distances onto the upper flanks according to the Secretaría de Seguridad y Protección Ciudadana. Ashfall was reported at around 1130 on 25 October in the municipalities of Calapan, Domingo Arenas (20 km NE), Huejotizingo (21 km E), San Nicolas de los Ranchos (15 km ENE), San Felipe Teotlacingo, Tlaltenango (35 km NE), San Miguel Xoxtla (35 km NE), Nealtican (21 km E), Atlixco (25 km SE), Juan C. Bonillas (33 km ENE), and San Martin Texmelucan (35 km NE) in Puebla, as well as in Tepoztlan (49 km W), Tlayacapan (40 km WSW), and Tlalnepantla (80 km NW), Morelos. The Gobierno de Puebla reported that during 0700-1100 on 26 October the Hermanos Serdán Airport (30 km NE) was closed so that workers could clear ash off the runways. The VAAC noted that during 26-27 October several dense ash plumes rose 7.9-8.8 km (26,000-29,000 ft) a.s.l. and drifted NE and NNE over the Gulf of Mexico. Minor ashfall was reported by CENAPRED in the municipality of Tetela del Volcán (20 km SW), Hueyapan (18 km WSW), and Tlaltizapán (65 km SW), Morelos, as well as in Tlaxcala (51 km NE), Chiautempan (55 km NE), and Zacatelco (45 km NE), Tlaxcala. Incandescent material was ejected above the crater rim during 27-28 October. 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), Gobierno de Puebla, Secretaría de Seguridad y Protección Ciudadana (SEGURIDAD)