Report on Santa Maria (Guatemala) — 14 February-20 February 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 February-20 February 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, 14 February-20 February 2007. 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 diffuse plumes from Santa María's Santiaguito lava dome complex drifted NE on 15 February. INSIVUMEH reported that avalanches descended the SW flank to the base of Caliente Dome and explosions produced diffuse ash plumes that drifted SW on 15 February. Explosions on 19 February produced ash plumes and ashfall to areas SW. According to the Washington VAAC diffuse plumes were visible on satellite imagery.
Geologic Background. 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.