Report on Santa Maria (Guatemala) — 6 December-12 December 2006
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 6 December-12 December 2006
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2006. Report on Santa Maria (Guatemala) (Sennert, S, ed.). Weekly Volcanic Activity Report, 6 December-12 December 2006. 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 satellite imagery, the Washington VAAC reported that explosions at Santa María's Santiaguito lava-dome complex produced ash plumes on 5, 7, and 10 December that drifted SW, NW, and W, respectively. INSIVUMEH reported constant incandescent avalanches on 8 December from the S and SE edge of Caliente dome and from the toe of the active lava flow on the SW flank. Ash plumes caused slight ashfall to the SW.
Geological Summary. Symmetrical, forest-covered Santa María volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile 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 vents, with activity progressing W towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.