CENAPRED reported that eruptive activity continued at Popocatépetl during 9-16 January. Long-period events totaling 6-64 per day were accompanied by steam-and-gas plumes that occasionally contained minor amounts of ash. The plumes mainly drifted ENE and NE. The seismic network recorded 14.5-23 daily hours of tremor, including both low- and high-frequency events. Minor amounts of ash fell in Nealtican (21 km E) during 11-12 January. Ashfall was also reported in Nativitas (40 km NE), Tetlatlahuaca (42 km NE), Zacatelco (45 km NE), Xicohtinco (45 km NE), Ayometla (46 km ENE), Papalotla (62 km NNW), Tenancingo, San Pablo del Monte (49 km E), Mazatecochco (50 km ENE), Tlaxcala (50 km NW), and Tepeyanco (47 km NW) in the state of Tlaxcala on 15 January and in Nealtican, Juan C. Bonilla (32 km ENE), and Tlaltenango in the state of Puebla on 16 January. 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.

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)