During 28 January to 2 February, small-to-moderate explosions occurred at Santa María's Santiaguito lava-dome complex. During 31 January to 2 February, collapses occurred at the SW edge of the lava dome within Caliente cone. Ash plumes were produced that rose to ~1 km above the lava dome, as well as small avalanches of volcanic blocks and ash. According to the Washington VAAC, on 2 February ash plumes were visible on satellite imagery rising to ~1 km above the volcano. INSIVUMEH recommended that tourists not visit the S part of the volcano.

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.

Sources: Washington Volcanic Ash Advisory Center (VAAC), Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)