Report on Santa Maria (Guatemala) — 16 March-22 March 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 March-22 March 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, 16 March-22 March 2005. Smithsonian Institution and US Geological Survey.
14.756°N, 91.552°W; summit elev. 3772 m
All times are local (unless otherwise noted)
During 16-21 March, several ash explosions occurred at Santa María's Santiaguito lava-dome complex. Ash plumes rose to a maximum height of 1.3 km above the volcano (~16,600 ft a.s.l.). Lava avalanches traveled down the SW flank of Caliente Dome. On 16 March, small amounts of fine ash fell in Xepax, Xecavioc, Llanos de Pinal, Las Majadas, and Quetzaltenango. During 19-20 March, ash fell E of the volcano in the town of Zunil.
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.