Report on Santa Maria (Guatemala) — 18 May-24 May 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 18 May-24 May 2016
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2016. Report on Santa Maria (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 May-24 May 2016. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
In a special report posted on 22 May, INSIVUMEH reported a high level of activity at Caliente cone, part of Santa María's Santiaguito lava-dome complex. Strong explosions generated dense ash plumes that rose as high as 2.5 km and drifted over 40 km S, SW, and W. Ashfall was reported in Colomba, Coatepeque, San Felipe Retalhuleu, El Nuevo Palmar, Las Marías, Aldea Loma Linda, San Marcos Palajunoj, the ranches of El Faro, La Florida Patzulin, and El Patrocinio, and other areas on the E flank. Pyroclastic flows traveled 2 km, down the E, S, and W flanks of Caliente cone and down the Cabello de Ángel and San Isidro drainages. The report also noted that during recent days ballistics were ejected as far as 3 km.
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.