Report on Santa Maria (Guatemala) — 24 September-30 September 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 24 September-30 September 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 24 September-30 September 2014. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
INSIVUMEH reported that on 24 September heavy rainfall triggered a hot lahar that descended the Cabello de Ángel River, a tributary of the Nimá I river drainage on the S flank of Santa María's Santiaguito lava-dome complex. The lahar carried tree trunks and branches, had a strong sulfur odor, and was 18 m wide and 2 m deep. During 27-28 and 29-30 September lava flows traveled down the S flank and steam plumes rose 400-500 m and drifted 600-800 m SW.
Geologic Background. Symmetrical, forest-covered Santa María volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile 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 vents, with activity progressing W towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.