CENAPRED reported that during 6-12 May the seismic network at Popocatépetl recorded 17-56 daily emissions mostly consisting of water vapor and gas. Nighttime crater incandescence was noted almost every night; sometimes the incandescence would become more intense with accompanying emissions. Explosions were detected at 0949 and 1113 on 7 May. The next day steam-and-gas emissions with low ash content drifted SSW. An explosion was detected at 0411. Ash was visible in water vapor-and-gas emissions during 10-11 May. The Alert Level remained at Yellow, Phase Two.

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)