INSIVUMEH reported that during 22-24 and 27-28 February explosions from Santa María's Santiaguito lava-dome complex generated ash plumes that rose 600-1,300 m above the complex and drifted WSW, W, and WNW. Pyroclastic flows were generated during 22-23 February, and ash fall was reported in El Rosario (45 km SW), Monte Bello (S), Palajunoj (SW), and Quetzaltenango (18 km WNW) on 23 February. Clouds of gas and tephra were also observed on 23 February. Constant avalanches descended the S flank during 23-24 and 27-28 February. Ash fall was reported in Monte Claro (S), San Marcos (46 km NW), Buena Vista (49 km NW), El Rosario, Monte Bello, and Palajunoj during 24 and 27-28 February. White plumes rose from the Caliente Cone and drifted WSW on 27 February.

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)