INSIVUMEH reported that during 12-13 May explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose 900 m above Caliente dome and drifted SE, depositing fine ash in areas downwind. During 14-15 May explosions produced ash plumes that rose 2 km above Caliente dome. Pyroclastic flows descended the SW and E flanks. Rumbling noises and block avalanches were also noted. Ash was deposited on the E, S, SW, and W flanks including the communities of Loma Linda, San Marcos, and Palajunoj. During 16-17 May explosions produced ash plumes that rose 0.7-1 km above Caliente dome and drifted SW. A pyroclastic flow traveled E.

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)