Report on Santa Maria (Guatemala) — 16 November-22 November 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 November-22 November 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 November-22 November 2005. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
During 17-21 November, several weak-to-moderate explosions occurred at Santa Maria's Santiaguito lava-dome complex, producing ash plumes to a maximum height of ~4.6 km (15,000 ft) a.s.l. Several small pyroclastic flows traveled down the SW and NE flanks of Caliente dome, stopping at the base of the dome. Avalanches of volcanic material spalled off of the fronts of active lava flows and traveled SW.
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.