Report on Popocatepetl (Mexico) — 31 August-6 September 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 August-6 September 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Popocatepetl (Mexico). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 31 August-6 September 2011. 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 on 29 August instances of emissions of gas, steam, and some ash from Popocatépetl increased. The next day an ash plume rose 1 km above the crater and drifted WNW, producing ashfall in San Pedro Nexapa (14 km NW) and Amecameca (19 km NW). CENAPRED noted that recent rain in the area may have contributed to the recent increase in activity. During 30-31 August there were 111 plumes of gas, steam, and some ash detected by the network, in addition to periods of harmonic tremor. Signals from detectors near drainages possibly indicated lahars. During 1-4 September the monitoring network registered 4-12 instances daily of emissions of gas, steam, and some ash. Periods of tremor continued to be detected.
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.