Report on Santa Maria (Guatemala) — 7 March-13 March 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 March-13 March 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 7 March-13 March 2012. 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 during 8-9 March explosions from Santa María's Santiaguito lava-dome complex generated ash plumes that rose 800-1,000 m above the crater and drifted W and SW. Block avalanches descended the SE and NW flanks. Ashfall was reported in the communities of Loma Linda, San Marcos, and Palajunoj. During 11-12 March explosions generated ash plumes that rose 800 m above the crater and drifted 20 km SSW. Ashfall was reported at the observatory, on the El Faro and Patzulin ranches, and in the village of Las Marías. Lava flows continued to produce avalanches.
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.