Report on Santa Maria (Guatemala) — January 1990
Bulletin of the Global Volcanism Network, vol. 15, no. 1 (January 1990)
Managing Editor: Lindsay McClelland
Santa Maria (Guatemala) Occasional low-density ash ejections; small lava flow spawns rock avalanches
Please cite this report as:
Global Volcanism Program, 1990. Report on Santa Maria (Guatemala). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 15:1. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199001-342030.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
Geologists noted several low-density ash ejections from Caliente Vent during 1 1/2 hours of observations beginning at 0945 on 3 January. The largest, at 1010, produced a gas/ash plume 1,000 m high. Subsequent episodes were smaller, ejecting plumes to a few hundred meters above the vent. A small lava flow that was emerging from Caliente Vent moved slowly down the dome's upper SE flank. The flow was a few tens of meters long, with associated rock avalanche deposits extending several hundred meters from its front. Recent avalanche deposits were also visible S and SW of the vent.
Caliente Vent, on the E side of Santiaguito dome, has been the site of continuous lava extrusion since 1975. A strong explosion from the Caliente Vent area on 19 July 1989 may have been the source of small lower stratospheric aerosol layers detected at several sites in August and September (see Atmospheric Effects, 14:8-9).
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: S. Halsor, Wilkes Univ; C. Chesner, Eastern Illinois Univ.