Report on Santa Maria (Guatemala) — 30 January-5 February 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 30 January-5 February 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 30 January-5 February 2013. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
On 30 January, INSIVUMEH reported that both an increasing height of ash plumes from explosions at Santiaguito lava-dome complex and a change in wind direction caused ashfall in the towns of Esperanza and San Mateo in Quetzaltenango. Dark gray plumes rose an average of 800 m above the complex and were accompanied by sulfur dioxide emissions.
During 30-31 January a series of small explosions produced ash plumes that rose 300 m and drifted NW. Active lava flows produced avalanches. During 31 January-1 February ashfall was reported in areas to the S. Two explosions on 3 February generated ash plumes that rose 700 m above the complex and drifted SW. Noise from avalanches were reported on 4 February. Two explosions on 5 February generated white-and-gray plumes that rose 700 m and drifted SW, causing ashfall in areas downwind.
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.