Report on Michoacan-Guanajuato (Mexico) — November 1985
Scientific Event Alert Network Bulletin, vol. 10, no. 11 (November 1985)
Managing Editor: Lindsay McClelland.
Michoacan-Guanajuato (Mexico) Fumarole temperatures increase
Please cite this report as:
Global Volcanism Program, 1985. Report on Michoacan-Guanajuato (Mexico). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 10:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198511-341060.
19.85°N, 101.75°W; summit elev. 3860 m
All times are local (unless otherwise noted)
"Fumarolic activity persisted at Ahuan vent on the SW flank. When temperatures were measured at Ahuan vent on 29 November, the hottest fumarole was 473°C, 70° higher than in April 1983, when Dartmouth scientists last measured temperatures at Parícutin. Several fumaroles over an area of about 50 m2 were hotter than 300°C. No physical changes in the area were apparent since April 1983."
Geologic Background. The widespread Michoacán-Guanajuato volcanic field contains over 1400 vents, including the historically active cinder cones of Parícutin and Jorullo, covering a 200 x 250 km wide area of Michoacán and Guanajuato states in west-central México. Cinder cones are the predominant volcanic form, but small shield volcanoes, lava domes, maars and tuff rings (many in the Valle de Santiago area), and coneless lava flows are also present. The shield volcanoes are mostly Pleistocene in age, and have morphologies similar to small Icelandic-type shield volcanoes, although the Michoacán-Guanajuato shields have higher slope angles and smaller basal diameters. Jorullo, which was constructed in the 18th century, and Parícutin, which grew above a former cornfield during 1943-52, are the two best known of the roughly 1000 small volcanic centers scattered throughout the volcanic field.
Information Contacts: C. Connor, B. Gemmell, and R. Stoiber, Dartmouth College.