The main crater (Caliente) of Santa María's active dome, Santiaguito, issued a 300-m-high explosion at 0631 on 14 October. Ash from the explosion blew E and small avalanches traveled down the E and S flanks. Brief explosions from the Caliente vent at Santiaguito were last reported in November 1993. However, it is likely that there has been near-continuous low-level activity since that time.

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.

Information Contacts: Eddie Sánchez and Otoniel Matías, INSIVUMEH.