Report on Santa Maria (Guatemala) — 3 September-9 September 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 3 September-9 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, 3 September-9 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 3-9 September INSIVUMEH reported white fumarolic plumes rising 200-300 m above Santa Maria’s active cone, Santiaguito. The active lava flow on the E flank continued to generate ash plumes and incandescence. On 4 September fine ash dispersed W over the area of Palajunoj (18 km SSW). On 6 September INSIVUMEH observed the lava flow advancing within the Nima 1 drainage.
INSIVUMEH reported that a strong lahar was detected by the seismic network and observed within Río Nima 1 on 7 September. Fines and blocks (up to 40 m) were mobilized, and 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 stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a 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.