Report on Santa Maria (Guatemala) — 15 November-21 November 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 15 November-21 November 2006
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2006. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 15 November-21 November 2006. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
Explosions at Santa María's Santiaguito lava-dome complex produced plumes that reached an altitude of 5.3 km (17,400 ft) a.s.l. on 15 November. Ashfall was reported from areas to the N. Lava flowed down the SW, S, and SE flanks of Caliente dome. On 17 November, explosions produced white-and-gray plumes that drifted SW, where light ashfall was reported. Based on satellite imagery, the Washington VAAC reported a series of brief gas-and-ash emissions on 19 November. Plumes drifted W.
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.