Report on Santa Maria (Guatemala) — 3 February-9 February 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 3 February-9 February 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, 3 February-9 February 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 strong explosions at Caliente cone, part of Santa María's Santiaguito lava-dome complex, began at 1023 on 7 February and generated rumbling sounds and shock waves detected as far as 25 km away. Pyroclastic flows descended the E and SE flanks. A dense mushroom-shaped ash cloud obscured the E, SW, and S parts of the volcano, and then rose 6 km above the crater. It drifted in multiple directions NW to SW. During 8-9 February white gas plumes rose 300 m above the lava dome and drifted E and SW.
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.