Report on Popocatepetl (Mexico) — May 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 5 (May 1993)
Managing Editor: Edward Venzke.
Popocatepetl (Mexico) Increased fumarolic activity; crater lake temperature rises
Please cite this report as:
Global Volcanism Program, 1993. Report on Popocatepetl (Mexico). In: Venzke, E (ed.), Bulletin of the Global Volcanism Network, 18:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199305-341090.
19.023°N, 98.622°W; summit elev. 5393 m
All times are local (unless otherwise noted)
Since January 1993 there have been increased reports of plumes, obvious in the afternoons, from residents of Puebla (45 km E, population 1.75 million). Geologists also reported increased fumarolic activity in February and March (18:02). Five observation posts have been installed in the vicinity of the volcano to monitor pH and temperature of water sources, and report plumes. The pH of the water has been consistent at 6.9, and the temperature is 17°C. A small circular lake (50 m diameter, 8 m deep) in the inner crater has increased in temperature from 29°C in 1986 to 51°C in March 1993. The primary sources of intense steam activity are at the bottoms of both the main and inner craters. Sulfur spots and deposits have been observed around the craters. At least 30 new vents on the floor of the main crater are releasing steam. Steam vents had not been observed since fieldwork in 1986. Daily visual monitoring is conducted from the meteorological station at Puebla Univ. No significant seismicity has been detected by the portable MQ-800 seismometer installed N of the volcano.
At least 15 scientific expeditions visited the summit in 1992 to investigate the eruptive history of Popocatéptl and prepare volcanic hazard maps. Seasonal activity, in the form of solfataric clouds from the inner crater, has been observed every year since 1986. From March-October 1992 a dense, greenish plume was observed, and a strong sulfur smell was detected in San Pedro (11 km SE) and La Magdalena (13 km SSE). A condensate of plume vapor had a pH of 3; water from the seasonal inner crater lake had a pH of 1.5. This type of plume was last reported during the 1943 eruption.
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: Alejandro Rivera Dominguez, Univ Autonoma de Puebla.