Report on Santa Maria (Guatemala) — 10 September-16 September 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 September-16 September 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, 10 September-16 September 2014. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
During 10-16 September INSIVUMEH reported white fumarolic plumes rising 150-500 m above Santa Maria’s active cone, Santiaguito. The active lava flow on the E flank continued to generate ash plumes and incandescence. On 14 September INSIVUMEH observed that the lava flow advancing within the Nimá 1 drainage had reached a total of 3,500 m from the summit.
INSIVUMEH reported hot lahars in the drainages of Cabello de Ángel and Río Nimá 1 on 11 September. Tree trunks and branches were entrained and the flow was 20 m wide and 2 m deep. Moderate vibrations could be felt from the ground as it passed the observatory; sulfur odors were also noticed.
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.