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Report on Santa Maria (Guatemala) — 21 September-27 September 2016


Santa Maria

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 21 September-27 September 2016
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2016. Report on Santa Maria (Guatemala) (Sennert, S, ed.). Weekly Volcanic Activity Report, 21 September-27 September 2016. Smithsonian Institution and US Geological Survey.

Weekly Report (21 September-27 September 2016)

Santa Maria

Guatemala

14.757°N, 91.552°W; summit elev. 3745 m

All times are local (unless otherwise noted)


INSIVUMEH reported that a strong explosion at 0345 on 25 September generated an ash plume that rose 2 km above Santa María's Santiaguito lava-dome complex and drifted W and SW. An explosion the next morning generated an ash plume that rose 1 km and drifted 15 km SW. A moderate explosion was detected by the seismic network at 0436 on 27 September; inclement weather prevented visual observations of the crater.

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 E 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.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)