Report on Santa Maria (Guatemala) — 12 December-18 December 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
12 December-18 December 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 12 December-18 December 2012. 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 during 12-13 December incandescence from Santa María's Santiaguito lava-dome complex was visible and lava flows were active on the flanks. During 13-14 December avalanches were produced from the fronts of lava flows on the SE flank. Ash plumes that rose from the avalanches drifted 10 km S, producing ashfall in La Florida (5 km S) and El Faro (SW flank). During 15-18 December incandescence emanated from the SW part of the lava dome. Avalanches were again produced from the fronts of lava flows on the SE flank. Ash plumes from the avalanches drifted 8 km during 15-16 December.
Geological Summary. 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.