Report on Santa Maria (Guatemala) — 19 May-25 May 2010

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 19 May-25 May 2010
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2010. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 19 May-25 May 2010. Smithsonian Institution and US Geological Survey.

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Santa Maria

Guatemala

14.757°N, 91.552°W; summit elev. 3745 m

All times are local (unless otherwise noted)


During 19-20 May, INSIVUMEH reported that hot lahars traveled down Santa María's Nima I, Nima II, and San Isidro rivers. The lahar in the San Isidro channel was 30 m wide and 1.5-2 m deep, emitted a sulfur odor, and carried blocks up to 2 m in diameter. Explosions from the Santiaguito lava dome complex produced ash plumes that rose to an altitude of 2.9-3.4 km (9,500-11,200 ft) a.s.l. and drifted SW. The next day, an explosion produced a plume that rose to an altitude of 3.3 km (10,800 ft) a.s.l. and drifted E and a pyroclastic flow that traveled SW. On 21 May another lahar descended the Nima II River.

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 3772-m-high stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 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.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)