Report on Santa Maria (Guatemala) — 4 May-10 May 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 May-10 May 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Santa Maria (Guatemala). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 4 May-10 May 2005. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
Continuing explosive activity from Santa María's Santiaguito lava-dome complex during 4-9 May sent ash columns as high as 1.3 km above the vent. Small collapses at the Caliente Dome generated pyroclastic flows 500-3,000 m long.
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 3772-m-high stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 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.