Report on Popocatepetl (Mexico) — February 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 2 (February 1993)
Managing Editor: Edward Venzke.
Popocatepetl (Mexico) Increased fumarolic activity; seismicity remains low
Please cite this report as:
Global Volcanism Program, 1993. Report on Popocatepetl (Mexico) (Venzke, E., ed.). Bulletin of the Global Volcanism Network, 18:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199302-341090.
19.023°N, 98.622°W; summit elev. 5393 m
All times are local (unless otherwise noted)
Increased fumarolic activity was observed from 4,500 m elevation during routine deformation studies on 25 February. A dilute white column, roughly the diameter of the summit crater, could be seen gently rising from the crater. The column was deflected by the wind immediately above the crater, even at low wind levels, and occasionally descended the flanks of the volcano, mainly to the NE. Snow on the NE crater rim was somewhat darkened, probably due to a wetting effect of the plume. The plume appeared to be mostly water vapor, with an occasional smell of sulfur. Tourists that have climbed to the summit reported that the crater is filled with a fog-like cloud, and there is a very strong smell of sulfur. The telemetered seismic station located at Tlamacas (4,000 m elevation on the NW flank) has recorded only normal background levels of seismicity, similar to those observed during the past three years. Based on current information, geologists believe that the increased fumarolic activity may be related to increased rainfall feeding the hydrothermal system. Installation of a third telemetered seismic station will be completed in the next few months. No change in fumarole activity was observed during fieldwork on 11 March, and seismic activity was low and within background levels.
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.
Information Contacts: S. De la Cruz-Reyna and H. Nolasco, Instituto de Geofísica, UNAM, Ciudad Universitaria, Delegación de Coyoacán; E. Ramos, CENAPRED.