Report on Santa Maria (Guatemala) — September 1978
Scientific Event Alert Network Bulletin, vol. 3, no. 9 (September 1978)
Managing Editor: David Squires.
Santa Maria (Guatemala) Mudflows in July and September; one person killed
Please cite this report as:
Global Volcanism Program, 1978. Report on Santa Maria (Guatemala). In: Squires, D (ed.), Scientific Event Alert Network Bulletin, 3:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN197809-342030.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
The Guatemalan press reports that blocks and ash erupted from Santiaguito on 23 July dammed the headwaters of three S-flank rivers; the Nimá I and II and the Tambor, forming a large lake. The breakup of these temporary dams on 24 July produced mudflows that damaged farms and destroyed bridges, isolating some villages. Damage was estimated at about $1 million, but no casualties were reported. Ash emission was continuing on 28 July. Another mudflow, on 2 September, killed one person and caused further damage.
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 stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a 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: Diario El Gráfico, Guatemala.