Report on Santa Maria (Guatemala) — 2 July-8 July 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 2 July-8 July 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, 2 July-8 July 2008. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
On 4 July, INSIVUMEH reported that an explosion from Santa María's Santiaguito lava dome complex produced an ash plume that rose to an altitude of 3.3 km (10,800 ft) a.s.l. and drifted SW. A lahar traveled S down the Nima I river, carrying tree limbs and blocks up to 50 cm in diameter. On 7 and 8 July, sounds resembling avalanches descending the flanks were reported; visual observations were hindered due to cloud cover.
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.