INSIVUMEH reported on 6 February that avalanches from lava flows on the W flank of Santa María's Santiaguito lava dome complex continued. Explosions produced ash-and-steam plumes that rose to an altitude of 3.9 km (12,800 ft) a.s.l. On 8 February, a strong phreatic explosion produced an ash plume that rose to an altitude of 4.7 km (15,400 ft) a.s.l. and caused ashfall in areas 4 km to the SW. Collapsing blocks of lava on the SW flank resulted in steam-and-ash plumes. On 12 and 18 February, lava flows on the S and SW flanks and avalanches of blocks that originated from the edge of the crater were noted. On 15, 18, and 19 February, explosions produced ash plumes that rose to altitudes of 4.6-4.7 km (15,100-15,400 ft) a.s.l. Ashfall was reported from areas 4 km to the SW on 15 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)