Report on Popocatepetl (Mexico) — 25 July-31 July 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 July-31 July 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, 25 July-31 July 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 25-31 July seismicity at Popocatépetl indicated continuing gas-and-ash emissions that sometimes probably contained ash; cloud cover prevented observations during most of this period. Incandescence from the crater was periodically observed. Steam-and-gas plumes were observed daily rising from the crater as high as 1.5 km above the rim. The plumes drifted in multiple directions. 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.