Report on Santa Maria (Guatemala) — 28 April-4 May 2010
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 28 April-4 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, 28 April-4 May 2010. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
On 30 April, INSIVUMEH reported that explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose to altitudes of 2.8-3.7 km (9,200-12,100 ft) a.s.l. and drifted N and NW. Ashfall was reported in towns downwind. Fumarolic plumes rose 300 m above Caliente dome. A lahar traveled S down the Nima I River, carrying blocks up to 90 cm in diameter. On 4 May an ash plume rose to a maximum altitude of 4 km (13,100 ft) a.s.l.
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.