Report on Santa Maria (Guatemala) — 8 March-14 March 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 8 March-14 March 2006
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2006. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 8 March-14 March 2006. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
On 6 March around 0733, a moderate explosion at Santa María's Santiaguito lava-dome complex produced an ash plume and pyroclastic flows. A strong explosion later that day at 1025 sent an ash plume ~3 km above the volcano (or 22,200 ft a.s.l.) that deposited ash throughout the volcanic complex. The explosion was accompanied by pyroclastic flows that traveled down the volcano's NE and SW flanks. Fine ash drifted S and fell on properties in that direction. During 10-13 March, several moderate explosions occurred. On 12 March, there were avalanches of volcanic blocks and ash. On 13 March, a pyroclastic flow traveled down the S flank of Caliente Dome.
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.