Report on Santa Maria (Guatemala) — 21 May-27 May 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 May-27 May 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, 21 May-27 May 2014. 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 on 22 May a lahar, the second since the 9 May eruption at Santa María's Santiaguito lava-dome complex, carried blocks up to 1 m in diameter as well as tree trunks. The lahar was 15 m wide and 2 m deep and had a strong sulfur odor. An explosion at 0608 on 23 May generated an ash plume that rose 700 m, drifted SW, and caused ashfall in parts of Monte Claro (S). On 24 May a lahar that was 25 m wide, 2 m deep, and had a sulfur odor descended the Nima I drainage, carrying tree trunks and branches. During 26-27 May gas-and-ash plumes rose 300-500 m and drifted SW.
Geologic Background. Symmetrical, forest-covered Santa María volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile 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 vents, with activity progressing W towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.