Report on Santa Maria (Guatemala) — 28 May-3 June 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 28 May-3 June 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 28 May-3 June 2014. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
INSIVUMEH reported that on 29 May a hot lahar descended the Nimá I river drainage on the S flank of Santa María's Santiaguito lava-dome complex, carrying blocks up to 50 cm in diameter as well as tree trunks and branches. The lahar was 25 m wide and 3 m deep and had a strong sulfur odor. Explosions during 31 May-1 June generated ash plumes that rose 600 m and drifted W and SW. Lahars on 1 and 3 June descended and caused flooding in the Nimá I, San Isidro (S), and Samala (E and S) rivers. On 2 June explosions produced ash plumes that rose 500 m, drifted W, and caused ashfall in Monte Bello and Loma Linda. Hot lahars with a sulfur odor again descended Nimá I. On 3 June a lava flow slowly descended the E flank of the 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 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.