Report on Santa Maria (Guatemala) — 21 September-27 September 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 September-27 September 2016
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2016. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 21 September-27 September 2016. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
INSIVUMEH reported that a strong explosion at 0345 on 25 September generated an ash plume that rose 2 km above Santa María's Santiaguito lava-dome complex and drifted W and SW. An explosion the next morning generated an ash plume that rose 1 km and drifted 15 km SW. A moderate explosion was detected by the seismic network at 0436 on 27 September; inclement weather prevented visual observations of the crater.
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.