Report on Santa Maria (Guatemala) — 22 January-28 January 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 January-28 January 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 22 January-28 January 2014. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
In a special report on 23 January, INSIVUMEH noted that a lava flow on the SE flank of Santa María's Santiaguito lava-dome complex became active; collapses from the lava-flow front generated avalanches and small pyroclastic flows that reached the base of the volcano. The report also noted that in recent months activity at Santa María was high, with explosions sometimes ranging from 40 to 45 explosions per day, generating ash plumes that rose 3-3.4 km. A change in wind direction on 23 January pushed the ash plume E and NE, causing ashfall in areas 10 km away. On 24 January explosions produced ash plumes that rose 500-700 m above the complex. A lava flow on the NE flank generated avalanches. Explosions during 27-28 January produced ash plumes that rose 600-800 m and drifted E, NE, and SW, causing ashfall in Santa María de Jesús (SE) and the El Rosario Palajunoj finca.
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.