Report on Santa Maria (Guatemala) — 16 May-22 May 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
16 May-22 May 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, 16 May-22 May 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 on 21 May a lahar traveled down Santa María's Rio Nima II drainage, carrying tree branches and 40-cm-wide lava blocks. On 22 May explosions produced ash plumes that rose 900 m above Caliente dome and drifted 10 km SE. Ashfall was reported in San Felipe (15 km SSW), El Nuevo Palmar (12 km SSW), and areas on the E flank.
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.