Report on Santa Maria (Guatemala) — 29 June-5 July 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
29 June-5 July 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, 29 June-5 July 2016. Smithsonian Institution and US Geological Survey.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
CONRED reported that an explosion at 1002 on 29 June at Caliente cone, part of Santa María's Santiaguito lava-dome complex, generated pyroclastic flows, and an ash plume that rose 2.5 km above the crater and drifted W and SW. Ash fell in El Faro. The report noted that more than 60 explosions had been detected so far this year. A strong explosion at 0920 on 1 July produced an ash plume that rose 2.5 km and drifted SW. A pyroclastic flow descended the S flank. Ashfall was reported in San Marcos Palajunoj, Loma Linda, San Martín Chile Verde, and Malacatán. A loud explosion in the evening of 2 July was followed by pyroclastic flows that descended the SW flanks. A 30-m-wide hot lahar triggered by rainfall descended the Nimá I and Cabello de Ángel drainages on 3 July, carrying rocks up to 1.5 m in diameter.
Geological Summary. 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.