Report on Santa Maria (Guatemala) — December 1996
Bulletin of the Global Volcanism Network, vol. 21, no. 12 (December 1996)
Managing Editor: Richard Wunderman
Santa Maria (Guatemala) Ash emissions and small collapses at Santiaguito dome
Please cite this report as:
Global Volcanism Program, 1996. Report on Santa Maria (Guatemala). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 21:12. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199612-342030.
14.756°N, 91.552°W; summit elev. 3772 m
All times are local (unless otherwise noted)
Santa María's large SW-flank crater that formed in a major eruption in 1902 contains Santiaguito, a dacite dome active almost continuously since 1922. In accord with this pattern, a small explosion was observed on 14 October. During 19 November-12 December 1996 several explosions of moderate-to-high intensity occurred almost daily. These explosions, three per hour, expelled ash in columns that rose variably 300-1,000 m above the active Caliente cone. The ash plumes, white-to-dark-gray in color, remained 8-15 minutes above the volcano before being blown W or SW or both directions. Light ashfalls were reported in the Rosario Palajunoi Estate (15 km from the volcano), La Finca Estate (~7 km SSW of the cone), over the woods in Siete Orejos area, but mostly in the proximity of Caliente cone.
Some of the explosions triggered small collapses and avalanches of blocks and ash down the Nimà Segundo river (SE flank) and along a channel opened by lava flows on the E flank of the volcano.
Geologic Background. Symmetrical, forest-covered Santa María volcano is one of the most prominent of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The 3772-m-high stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 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 westward-younging vents, the most recent of which is Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.
Information Contacts: Otoniel Matías, INSIVUMEH.