Report on Santa Maria (Guatemala) — 3 January-9 January 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 3 January-9 January 2007
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2007. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 3 January-9 January 2007. 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 37 weak to moderate explosions from Santa María's Santiaguito lava-dome complex on 4 January. The moderate explosions caused ashfall S and SE in the ranching areas of Monte Bello and Monte Claro. About 21 block-and-ash flows were also observed. On 5 January, explosions produced ash clouds that rose to 4.3-4.8 km (14,000-15,700 ft) a.s.l. Ashfall was noted from areas S and SE. The Washington VAAC reported that ash puffs were visible on satellite imagery during 7-8 January.
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.