Report on Popocatepetl (Mexico) — 2 May-8 May 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 2 May-8 May 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Popocatepetl (Mexico). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 2 May-8 May 2012. Smithsonian Institution and US Geological Survey.
19.023°N, 98.622°W; summit elev. 5393 m
All times are local (unless otherwise noted)
CENAPRED reported that during 2-3 May activity at Popocatépetl increased significantly. Spasmodic tremor was detected along with a dense and continuous plume of gas and ash that drifted W, NW, and NNE. Ash fell in multiple areas, including Amecameca (20 km NW), Atlautla, Ozumba (18 km W), Ecatzingo (15 km SW), Chalco (35 km NW), and some parts of SE México City (70 km NW). On 3 May gas-and-ash plumes rose 1.5 km above the crater and drifted W and NE. Incandescent fragments ejected from the crater landed on the flanks as far as 800 m away. Explosion-generated gas-and-ash plumes the next day rose 2.5 km above the crater and drifted NW. Spasmodic tremor was detected along with a dense and continuous plume of gas and ash that drifted WNW. Later that day gas-and-ash plumes rose 1 km. During 5-6 May gas-and-ash plumes rose 1.5 km above the crater and drifted N, NE, and E. Light ashfall was reported in Atlixco (25 km SE), San Juan Tianguismanalco (22 km SE), Tochimilco (16 km SSE), San Pedro Benito Juárez (10 km SE), and San Nicolás de los Ranchos (16 km ENE). During 5-7 May incandescent fragments ejected from the crater landed on the flanks as far as 500 m away. A gas-and-ash plume drifted ESE on 7 May. The next day activity remained high; seismic events were accompanied by dense and continuous plumes of steam, gas, and ash that drifted mainly ESE. The Alert Level remained at Yellow Phase Three.
Geologic Background. 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.