Report on Santa Maria (Guatemala) — September 2011
Bulletin of the Global Volcanism Network, vol. 36, no. 9 (September 2011)
Managing Editor: Richard Wunderman.
Santa Maria (Guatemala) Eruption on 26 April 2010; ongoing activity through September 2011
Please cite this report as:
Global Volcanism Program, 2011. Report on Santa Maria (Guatemala). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 36:9. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN201109-342030.
14.757°N, 91.552°W; summit elev. 3745 m
All times are local (unless otherwise noted)
The following report provides information from May 2010 through mid-October 2011 on Santa Maria volcano and its active dome complex, Santiaguito. The last report (BGVN 35:03) covered activity form 2008 to April 2010. The sources for this report are Guatemala's Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hidrologia (INSIVUMEH) and Washington Volcanic Ash Advisory Center (VAAC). Santa Maria's eruptive history from the Global Volcanism Program database identifies the current eruption as beginning 22 June 1922 and continuing to mid-October 2011. The database's criteria for an eruption ending requires at least a 3-month pause in volcanic emissions (Siebert and others, 2010).
A recent report concerned the eruption of 26 April 2010, an event mentioned at the end of our last report (BGVN 35:03). A table summarizes some significant activity during the current reporting period. It is notable that during about nine months of 2011 (up to early October), MODVOLC measured thermal alerts several times each month (in each instance covering an area of 1 to 3 pixels). In comparison, during 2009, seven thermal alerts were measured and, during 2010, three alerts were measured.
More details on the 26 April 2010 eruption. Chigna (2010) noted the 26 April 2010 eruption of Santiaguito was associated with four large seismic events (M 3.9 at 0624, M 4.92 at 0648, M 5.89 at 0723, and M 5.72 at 0758). The seismic network recently established at the volcano permitted first-time recognition of some seismic signals known as tornillos ['screws' in Spanish; defined by Morrissey and Mastin (2000) as monochromatic, long period seismic events lasting a few minutes, with long codas of progressively decreasing amplitude that may be eruption precursors] (figure 34a). Pyroclastic flows were generated within the gullies on the S flank. An ash column rose to an altitude of 15 km, drifting to the W, NW, N, NE, and E, causing closure of village schools SW of Santiaguito and in the Quetzaltenango area. The ashfall was reported out to 7.3 km from the volcano; civil aeronautics alerted air traffic to avoid the plume within a radius of 80 km.
|Figure 34. Examples of seismic records at Santa Maria. (a) Tornillo (screw) event. (b) Pyroclastic flow due to dome collapse; arrows indicate the onset of the primary events. Both seismic records taken from Chigna (2010).|
Activity from May 2010 to early-October 2011. Tables 3 and 4, summarizing activity from May 2010 through early-October 2011, document nearly continuous explosions, plumes, and pyroclastic flows. Various mass wasting processes were common, particularly block avalanches and lahars, often set into motion by precipitation.[Skip text table]
Date (2010) Explosions noted Plume color Plume Height Drift and composition Direction Other Activity 07 May 17 weak to moderate Gray 2.9-3.4 km SW 10 May — White 75 m — 19 May Yes Ash 2.9-3.4 km SW Hot lahars carried blocks 20 May Yes — 3.3 km E Pyroclastic flow to SW 04 Jun — — — — Lahar carried blocks 19-20 Jul 24 in 48-hour period Ash 300-900 m SE, W 05-06 Aug — Steam — SW Lahars carried trees, blocks 01 Sep — Ash 100 m SE Pyroclastic flow to SW 02 Sep Yes Ash 500-1,000 m W, SW Block avalanches on W flank 06 Sep Yes Ash 500-1,000 m W, SW 11 Sep Yes Ash 1 km E, SE Pyroclastic flows (2) to 3 km SW 13 Sep — White 100 m S 22 Oct Yes Ash 300 m SW Block avalanches on S and SW flanks 26 Oct — Steam 150 m — 29 Oct Yes Ash 900 m SW Pyroclastic flow down SW flank to 5 km S 31 Oct — Ash — W 17, 22 Nov Yes Ash 0.7-1 km E, SE 19 Nov — — — — Ashfall to the S 08 Dec Yes Ash 700 m SE Block avalanches; ashfall to SE 10 Dec — Ash — 21 km W 13-14 Dec Yes Ash 300-700 m SE Block avalanches; pyroclastic flows 29-30 Dec Yes Ash 300-600 m S, SE Ashfall
Date (2010) Explosions noted Plume color Plume Height Drift and composition Direction Other Activity 01 Jan — — — W Satellite thermal anomalies 03-04 Jan Yes Ash 700m SW Avalanches to W flank 05-06 Jan Yes Ash 400-500 m SW 08 Jan — Ash? — 30 km SSW 10-11 Jan Yes Ash 600 m SW, W Avalanches on S and E flanks 20-21 Jan — Ash 4.3-5.2 km SW Avalanches; rockfalls 23-24 Jan — Ash 300 m N 02-03 Feb Yes Ash 300 m
References. Chigna, G., 2010, Eruption of Santiaguito (1402-03) 26 April 2010. INSIVUMEH (URL: http://www.insivumeh.gob.gt/).
Morrissey, M., and Mastin, L., 2000, Vulcanian eruptions, p. 463-475, in Sigurdsson, H. (ed), Encyclopedia of Volcanoes, Academic Press, San Diego.
Siebert, L., Simkin, T., and Kimberly, P., 2010, Volcanoes of the World, 3rd ed., Berkeley: University of California Press, 568 p.
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: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hydrologia (INSIVUMEH), Unit of Volcanology, Geologic Department of Investigation and Services, 7a Av. 14-57, Zona 13, Guatemala City, Guatemala (URL: http://www.insivumeh.gob.gt/inicio.html); Washington Volcanic Ash Advisory Center (VAAC), Satellite Analysis Branch (SAB), NOAA/NESDIS E/SP23, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20748, USA (URL: http://www.ssd.noaa.gov/VAAC/); MODVOLC-HIGP, Hawai'i Institute of Geophysics and Planetology (HIGP) MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).