Report on Santa Maria (Guatemala) — 21 March-27 March 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 March-27 March 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, 21 March-27 March 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 that explosions from Santa María's Santiaguito lava dome complex produced ash-and-steam plumes that rose to altitudes of 3.8-4.8 km (12,500-15,700 ft) a.s.l. during 21-22 and 25 March and drifted W. Ashfall was reported from nearby areas. On 25 and 26 March, avalanches occurred from lava-flow fronts on the SW flanks of Caliente Dome. On 27 March, an explosion produced a pyroclastic flow that traveled down the SW flank.
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.