Report on Santa Maria (Guatemala) — 9 August-15 August 2023
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 9 August-15 August 2023
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2023. Report on Santa Maria (Guatemala) (Sennert, S, ed.). Weekly Volcanic Activity Report, 9 August-15 August 2023. 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 eruptive activity continued at Santa Maria’s Santiaguito lava dome complex during 9-15 August. Incandescence from the dome was visible during most nights and early mornings, and occasionally from the SW lava flow. Lava extrusion continued and formed a more prominent high point in the middle of the dome that was the main source of collapses and occasional short pyroclastic flows. Daily weak-to-moderate explosions generated gas-and-ash plumes that rose 700-1,000 m above the dome and drifted NW, W, and SW. Explosions also triggered incandescent avalanches that descended the dome’s flanks in all directions, and into the Zanjón, Seco, and San Isidro drainages. Incandescence was observed at the crater and along lava flow margins during the night and early morning.
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.