CENAPRED reported that ongoing activity at Popocatépetl during 14-20 June included 39-180 daily steam-and-gas emissions, sometimes containing minor amounts of ash. According to the Washington VAAC, daily ash plumes rose to maximum altitudes of 5.8-6.7 km (19,000-22,000 ft) a.s.l., or up to 1.3 km above the summit, and drifted generally drifted S, SW, and W, causing ashfall in local communities. At 0337 on 17 June CENAPRED noted a moderate explosion that ejected ballistic material as far as 2.5 km from the crater. Minor ashfall was reported in Hueyapan (16 km SSW), Tetela del Volcán (18 km SW), Yecapixtla (29 km SW) and Ayala (47 km SW) in Morelos, as well as Amecameca (18 km NW) and Atlautla (16 km W) in the State of Mexico during 14-15 June. Minor ashfall during 15-16 June was reported in Amecameca, Ayapango (21 km NW), Chalco (37 km NW), Ecatzingo (15 km SW), Temamatla (30 km NW), Tepetlixpa (20 km W), Tlalmanalco (26 km NW) and Tenango del Aire (28 km NW) in the State of Mexico. Reports of minor ashfall came from Ixtapaluca (42 km NW), Valle de Chalco (44 km NW), La Paz (50 km NW), Nezahualcóyotl (56 km NW), Amecameca, Atlautla, Ayapango, Cocotitlan (34 km NW), Chalco, Ecatzingo, Temamatla, Tenango del Aire, Tepetlixpa and Tlalmanalco in the State of Mexico during 16-17 June. Minor ashfall during 18-19 June was again reported in Tepoztlan (49 km W), Cuernavaca (63 km WSW), Ocuituco (24 km SW), Cuautla (43 km SW), Atlatlahucan (30 km SW), Jiutepec (59 km SW) and Emiliano Zapata (62 km SW), Morelos; Ixtapaluca, La Paz, Valle de Chalco, Nezahualcóyotl (54 km NW), Chicoloapan (48 km NW), Atlautla, Ecatzingo, Tonatico in the State of Mexico. Seismicity included periods of low-to-moderate amplitude, high-frequency tremor for 274-567 minutes each day, three volcano-tectonic earthquakes of M 1.2-1.5 were recorded during 15-16 June, and 19 minutes of low-amplitude, harmonic tremor during 16-17 June. 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)