Report on Santa Maria (Guatemala) — 20 June-26 June 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 June-26 June 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, 20 June-26 June 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 22 June an explosion from Santa María's Santiaguito lava-dome complex produced an ash plume that rose 700 m above Caliente dome and drifted E and SE. Ashfall was reported in Santa María de Jesús. Block avalanches from the dome traveled down the SE flank. On 23 June lahars traveled S down the Rio Nima I and San Isidro drainages, carrying tree branches and blocks 30-80 cm in diameter. During 25-26 June an explosions generated an ash plume that rose 600 m and drifted SE. Ash fell on the San José and La Quina ranches. Block avalanches again traveled down the SE flank.
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.