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Report on Santa Maria (Guatemala) — 5 July-11 July 2017


Santa Maria

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 5 July-11 July 2017
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2017. Report on Santa Maria (Guatemala) (Sennert, S, ed.). Weekly Volcanic Activity Report, 5 July-11 July 2017. Smithsonian Institution and US Geological Survey.

Weekly Report (5 July-11 July 2017)

Santa Maria

Guatemala

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

All times are local (unless otherwise noted)


INSIVUMEH reported that on 5 July a moderate lahar descended the Cabello de Ángel drainage, a tributary of the Nimá I river. Near the El Faro estate, the lahar was 30 m wide and 1 m deep, and carried blocks 50 cm in diameter. Weak explosions on 7 July generated white plumes that rose 700 m and drifted 2 km SE; minor ashfall was reported in the ranches of La Florida (5 km S) and Monte Claro (S). Weak avalanches of material traveled short distances down the E flank. Explosions during 10-11 July generated ash plumes that rose 600 m and drifted SW, causing some ashfall in La Florida.

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)