Report on Santa Maria (Guatemala) — 24 September-30 September 2008

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 24 September-30 September 2008
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2008. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 24 September-30 September 2008. 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)


Based on information from the Tegucigalpa MWO, the Washington VAAC reported that on 18 September an ash plume from Caliente dome in Santa María's Santiaguito complex rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted SSW. INSIVUMEH reported on 24 September that explosions produced ash plumes that rose to altitudes of 2.8 km (9,200 ft) a.s.l. and drifted SW. Avalanches of material from the top of the lava dome descended the flank and lava flows traveled SW.

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.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center (VAAC)