Report on Santa Maria (Guatemala) — 31 December-6 January 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 December-6 January 2009
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2008. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 31 December-6 January 2009. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
Based on analysis of satellite imagery, the Washington VAAC reported that two small ash plumes from Santa María's Santiaguito lava dome complex drifted ESE on 1 January. During 4-5 January, gas and steam plumes possibly containing some ash drifted SW and WSW. INSIVUMEH reported that on 5 and 6 January fumarolic plumes drifted 100 m above the crater. Five explosions produced ash plumes that rose to altitudes of 2.8-3 km (9,200-10,000 ft) a.s.l. and drifted W and SE. A few avalanches originating from a lava flow descended the W flank.
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.