Report on Santa Maria (Guatemala) — 4 March-10 March 2009
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 4 March-10 March 2009
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2009. Report on Santa Maria (Guatemala) (Sennert, S, ed.). Weekly Volcanic Activity Report, 4 March-10 March 2009. 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 analysis of satellite imagery, the Washington VAAC reported that during 4-6 March ash plumes from Santa María's Santiaguito lava dome complex drifted W. On 6 and 10 March, INSIVUMEH reported that explosions produced ash plumes that rose to altitudes of 2.8-3.4 km (9,200-11,200 ft) a.s.l. and drifted SW, NW, and N. Ashfall was reported in areas downwind.
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.