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Report on Turrialba (Costa Rica) — November 2001

Bulletin of the Global Volcanism Network, vol. 26, no. 11 (November 2001)
Managing Editor: Richard Wunderman.

Turrialba (Costa Rica) Seismic and fumarolic activity during January 2000-August 2001

Please cite this report as:

Global Volcanism Program, 2001. Report on Turrialba (Costa Rica). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 26:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200111-345070.

Volcano Profile |  Complete Bulletin


Turrialba

Costa Rica

10.025°N, 83.767°W; summit elev. 3340 m

All times are local (unless otherwise noted)


During January 2000 to at least August 2001, seismic and fumarolic activity continued at Turrialba (table 5). On 12 March 2000 an M 3.2 earthquake was registered at a depth of 7 km, 6.5 km E of the active crater. The EDM lines (radial lines of distances) as well as the dry clinometers did not show significant changes during 2000.

Table 5. Summary of earthquakes and fumarolic temperatures at Turrialba during January 2000 to August 2001, registered by a seismograph at station VTU, located ~0.5 km SE of the active crater. Microearthquakes were defined as earthquakes registered on the local seismic system with amplitudes under 15 mm. Missing months indicate that no data was available for that month. NR indicates information not reported. Courtesy of OVSICORI-UNA.

Month AB earthquakes LF earthquakes Micro-earthquakes Total earthquakes Maximum fumarolic temperature (°C) Comment
Jan 2000 29 2 33 64 NR Seismicity registered only 13 days.
Feb 2000 91 -- 75 166 NR Seismicity registered only 16 days.
Mar 2000 44 -- 65 113 91 --
Apr 2000 NR NR NR NR 90 --
May 2000 286 5 330 616 NR --
Jul 2000 50 -- 104 167 90 --
Aug 2000 76 -- 148 229 89 --
Sep 2000 243 -- 244 493 89 --
Oct 2000 NR NR NR NR 93 --
Mar 2001 399 948 718 2075 NR --
May 2001 128 -- 334 464 92 An average of 15 earthquakes per day.
Jun 2001 3 -- 185 194 92 Six VT earthquakes.
Jul 2001 24 -- 310 334 91 --
Aug 2001 14 -- 261 275 90 --

Fumarolic activity was persistent in the N, NW, NE, and E walls of the main crater. Fumarolic activity in the S and SW walls diminished by July 2000 and began to reappear during October 2000. Activity in the N wall during May 2001 was more vigorous than previously. Small landslides persisted in the walls of the main crater, covering some fumaroles at the bottom and revealing other new ones.

During March 2001 sulfur precipitation and gaseous emanations in the internal walls occurred throughout most of the central craters. Gaseous activity also persisted in the W crater walls. During June 2001, a small patch of vegetation at the center of the main crater showed partial burns due to the gas escaping in the NE part of the main crater.

Geologic Background. Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of IrazĂș volcano overlooking the city of Cartago. The massive edifice covers an area of 500 km2. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.

Information Contacts: Observatorio Vulcanologico y Sismologico de Costa Rica, Universidad Nacional (OVSICORI-UNA), Apartado 86-3000, Heredia, Costa Rica.