Report on Santa Maria (Guatemala) — August 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 8 (August 1987)
Managing Editor: Lindsay McClelland.
Santa Maria (Guatemala) Lava flow from dome; many avalanches; explosions
Please cite this report as:
Global Volcanism Program, 1987. Report on Santa Maria (Guatemala). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 12:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198708-342030.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
An incandescent block lava flow continued to emerge from Cono Caliente (the active crater on the E side of the dome), advancing down the S flank. By the end of July its front was between 1,200 and 1,300 m elevation in a canyon 80 m wide and 30 m deep, about 1.5 km from the Nimá II river. Numerous avalanches occurred from the flow front and along its channel. There were some reports of explosions from the flow front; fumaroles and a gaseous odor were noted there by geologists. Sporadic explosions from Cono Caliente ejected light-colored ash, and gas emission was continuous.
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: E. Sánchez, INSIVUMEH.