Report on Santa Maria (Guatemala) — 11 January-17 January 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 11 January-17 January 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, 11 January-17 January 2006. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
During 11-13 January, several explosions occurred at Santa María's Santiaguito lava-dome complex, producing ash plumes that rose to ~1.5 km above the volcano (or 17,300 ft a.s.l.) and drifted SW. Lava avalanches originated from the SW edge of the Caliente dome. An explosion on the morning of 11 January generated a small pyroclastic flow that traveled down Caliente dome to the NE. INSIVUMEH reported on 16 January that a slight decrease in explosive activity was observed at the volcnao during the previous month, with small-to-moderate explosions producing ash clouds that rose to ~1 km above the crater (or 15,650 ft a.s.l.). On the 16th there were reports of a small amount of ashfall in the urban area of San Felipe Retalhuleu.
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.