Report on Santa Maria (Guatemala) — February 1977
Natural Science Event Bulletin, vol. 2, no. 2 (February 1977)
Managing Editor: David Squires.
Santa Maria (Guatemala) Ash emission increases; ashfall zone extends 70 km to the coast
Please cite this report as:
Global Volcanism Program, 1977. Report on Santa Maria (Guatemala). In: Squires, D (ed.), Natural Science Event Bulletin, 2:2. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.NSEB197702-342030.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
Beginning about 25 January, ash emission from Santiaguito increased significantly. On 8 February, an ash cloud reduced visibility in Quetzaltenango (12 km NNE) to about 10 m and coated vegetation and roofs. On 9 February, ash was still falling "incessantly" on Quetzaltenango. The ashfall zone extends at least 70 km to the Pacific coast, where an "extensive zone" is reportedly affected. The ashfall has been annoying, but no damage or casualties have been reported.
Geologic Background. Symmetrical, forest-covered Santa María volcano is one of the most prominent of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The 3772-m-high stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank and was formed during a catastrophic eruption in 1902. The renowned plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic-andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four westward-younging vents, the most recent of which is Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.
Information Contacts: Guatemalan press.