Report on Santa Maria (Guatemala) — 9 February-15 February 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 February-15 February 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 9 February-15 February 2011. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
Based on information from INSIVUMEH, the Washington VAAC reported that ash observed in satellite imagery from a pyroclastic flow at Santa María's Santiaguito lava dome complex on 9 February had dissipated. INSIVUMEH reported that early on 10 February explosions produced ash plumes that rose almost 800 m above Caliente dome. Cloud cover prevented observations through the day. Seismic data suggested a block avalanche at 1230. During 11-12 February ash from pyroclastic flows was detected in satellite imagery and rose to altitudes of 3.4-4.3 km (11,000-14,000 ft) a.s.l. On 13 February INSIVUMEH noted that a pyroclastic flow was detected, but not visually observed due to cloud cover. Explosions during 13-15 February produced ash plumes that rose 300-1,200 m above the dome. Block avalanches originated from the E crater rim. Ash fell in the La Florida and El Faro fincas (ranches) to the S.
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.