Global Volcanism Program

29 May-4 June 2013

OVSICORI-UNA reported that on 29 May a pilot flying past Turrialba about 40 km away observed a blackish plume. Officials from the Parque Nacional Volcán Turrialba observed a gas plume that was slightly darker than usual between 0730 and 0745; seismic records showed no abnormal activity at those times or during the previous 48 hours. In addition, web camera images showed no noticeable ash emissions since 23 May. Gas plumes over 750 degrees Celsius were emitted from Boca 2010 (on the W wall) and Boca 2012 (on the E wall). The plume from Boca 2010 was whiter than the plume emitted from Boca 2012, mainly due to the difference in the ratio of magmatic gases and aerosols, and no ash.

On 4 June slight ashfall was reported in Pacayas and San Pablo in Oreamuno de Cartago (25 km SW). An observer in the National Park noted that between 1400 and 1500 gas emissions were slightly stronger and also grayish.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Available Weekly Reports

29 May 2013 Back to Top

OVSICORI-UNA reported that on 29 May a pilot flying past Turrialba about 40 km away observed a blackish plume. Officials from the Parque Nacional Volcán Turrialba observed a gas plume that was slightly darker than usual between 0730 and 0745; seismic records showed no abnormal activity at those times or during the previous 48 hours. In addition, web camera images showed no noticeable ash emissions since 23 May. Gas plumes over 750 degrees Celsius were emitted from Boca 2010 (on the W wall) and Boca 2012 (on the E wall). The plume from Boca 2010 was whiter than the plume emitted from Boca 2012, mainly due to the difference in the ratio of magmatic gases and aerosols, and no ash.

On 4 June slight ashfall was reported in Pacayas and San Pablo in Oreamuno de Cartago (25 km SW). An observer in the National Park noted that between 1400 and 1500 gas emissions were slightly stronger and also grayish.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

22 May 2013 Back to Top

OVSICORI-UNA reported that an eruption from Turrialba's West Crater on 21 May was preceded by seismic activity characterized by more than 150 volcanic earthquakes per day since 18 April.

Increased gas emissions were detected on 20 May, producing a sky-blue plume visible from nearby areas. Hybrid earthquakes also increased and became numerous at 0452 on 21 May. Continuous harmonic tremor followed and then increased at 0720. Eruptions from West Crater occurred at 0830 and after 1100 from two vents which opened in January 2010 (Boca 2010, on the W wall) and January 2012 (Boca 2012, on the E wall). The eruptions generated ash plumes that rose more than 500 m; ashfall was reported in the area of Picada (N), and in San José (35 km WSW) and Heredia (38 km W) of Ipís de Guadalupe, Goicoechea (28 km WSW), la Fazio, Zetillal (43 km W), San Isidro-San Pedro de Coronado, and San Luis de Santo Domingo (28 km W). At around 1200 ash emissions ceased and seismicity decreased.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

15 February 2012 Back to Top

OVSICORI-UNA reported that while conducting field work at Turrialba during 2-3 February, scientists observed incandescence with temperatures between 600-700 degrees Celsius from the three main vents of the W crater. The vents are comprised of the 2010 vent (on the SW rim), the 2011 vent (on the N side at the bottom of the crater), and the 2012 vent (on the SE flank).

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

18 January 2012 Back to Top

OVSICORI-UNA reported that on 12 January a new vent opened on the SE flank of the W crater of Turrialba and ash emissions drifted NNE; ashfall was reported in Tres Ríos (27 km SW). During the evening of 18 January scientists observed gas emissions and ejection of tephra from the vent. They also observed reddish flames from combusting gas, estimated to be about 700 degrees Celsius. Residents reported a dark ash cloud and ashfall in La Central (4 km SW). An OVSICORI-UNA pilot observed an ash plume that rose to altitudes of 4.3-6.1 km (14,000-20,000 ft) a.s.l. on 18 January.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

11 January 2012 Back to Top

OVSICORI-UNA reported that on 11 January local people around Turrialba heard several instances of rumbling. On 12 January an eruption occurred from a fissure on the SE flank of the main crater, in an area called La Quemada. An ash plume rose 500 m above the crater and drifted NNW, rising to an altitude of 4 km (13,000 ft) a.s.l. Later that day residents reported: a dark plume from La Quemada and a white vapor plume that rose from the fumarolic vent formed in the main crater on 5 January 2010.

According to a news article, the Turriabla National Park closed on 12 January and the National Emergency Commission (CNE) raised the Alert Level from Green to Yellow in the communities of La Central (34 km SW), Santa Cruz (7 km SE), and around the perimeter of the crater. Towns of Jiménez (21 km N), Oreamuno (45 km SW), Alvarado (38 km SW), and Cartago (25 km SW) remained at Alert Level Green.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) , La Nacion

15 June 2011 Back to Top

OVSICORI-UNA reported that on 9 June scientists conducting fieldwork at Turrialba observed a new crater lake in the W crater, which opened in January 2010 and was the center of the most recent activity. Since February, rock landslides along with abundant mud and clay had accumulated in the bottom of the crater, blocking the vent. Meteoric water from rains starting in May had formed a light-green-colored lake that was 70 by 70 m and about 1 m deep. Minor bubbling in the SW and NE shores was noted, and steam and sulfur dioxide gas emissions rose from many fumarolic vents around the crater.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

12 January 2011 Back to Top

According to news articles, people near Turrialba reported minor ashfall 2 km SE, rumbling noises, and a strong sulfur odor on 14 January. A few people were evacuated. OVSICORI-UNA noted that a blue and white gas plume rose from Turrialba the next day.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) , La Nacion

11 August 2010 Back to Top

The Washington VAAC reported that on 15 August ash emissions from Turrialba were seen through an OVSICORI-UNA web camera, about 600 m E of the active crater. Satellite imagery showed an approximately 10-km-wide ash plume drifting 15 km W.

Sources: Washington Volcanic Ash Advisory Center (VAAC)

21 July 2010 Back to Top

Based on web camera views of Turrialba, the Washington VAAC reported that on 24 July a plume of steam, gas, and ash drifted W. Over the next three hours the plume became more diffuse and steam-rich.

Sources: Washington Volcanic Ash Advisory Center (VAAC)

12 May 2010 Back to Top

OVSICORI-UNA reported that during April a majority of the gases emitted from Turrialba originated from the vent that opened in January, producing plumes that rose 2 km. Gas was emitted from other areas including from fissures SW of the W crater and from multiple vents and fissures in the main crater. Gas plumes mainly drifted NW, W, and SW, coincident with areas that had the most vegetation impact from the plumes.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

10 March 2010 Back to Top

OVSICORI-UNA reported that scientists visited Turrialba at night on 7 March. A gas plume, commonly seen drifting with prevailing winds, was seen that night rising 1.5 km above the crater and drifting NW. Noises from the crater were described as sounding like a jet engine and rumblings. A vent, formed in January, emitted gas at temperatures between 300 and 320 degrees Celsius. Small blocks 3-12 cm in diameter and different colors dominated the surface around the vent. Lithics ejected 30-50 m away from the vent measured 170 degrees Celsius. Incandescence seen at night originated from the vent which ejected reddish-colored tephra.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

13 January 2010 Back to Top

Based on multiple METAR weather notices during the previous few days, the Washington VAAC reported on 16 January that gas plumes containing some ash rose from Turrialba. Ash was not seen in satellite imagery that day or the next.

Sources: Washington Volcanic Ash Advisory Center (VAAC)

6 January 2010 Back to Top

OVSICORI-UNA reported that a phreatic eruption from Turrialba that began on 5 January was preceded by a day of increased seismicity and about 30 minutes of almost constant tremor. Two events detected about 15 minutes apart were followed by reports of ashfall as far away as 30 km. Field observations on 6 January revealed that two small vents had opened and joined together on the SE inner wall of the SW crater. Gas emission temperatures were more than 350 degrees Celsius. On 8 January seismic activity and gas emissions decreased. Observations the next day revealed that the combined vent was about 25 m wide and 80 m long. Around 60 people had evacuated from nearby farms.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

30 December 2009 Back to Top

On 5 January, OVSICORI-UNA reported that an eruption from Turrialba produced ashfall in local areas, particularly in areas to the SW, including near Irazú volcano (11 km SW). According to news articles, about 20 people evacuated the area.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) , Reuters

23 September 2009 Back to Top

On 25 September, scientists from OVSICORI-UNA reported results from three field trips to Turrialba to inspect new fissures and to assess the impact of gases on surrounding areas. Winds carrying toxic gases 10 km SW, to the S side of Irazú volcano, caused trees to exhibit mild burns to a greater degree than effects from the previous year. Vegetation within a 4-km-radius on the W, NW, and E flanks was also burned more severely that previously noted. Several elongated fissures in the rim S of the W crater were documented, as well as 1 km down slope NW of the crater. One E-W-trending crack that was first seen several months before had opened up as much as 12 cm, and emitted gas and vapor at 90 degrees Celsius. On the NW lower flanks, at least three radial fissures emitted high gas-and-vapor plumes. Some fissures near the summit were 5-10 cm wide. The last of the remaining settlers in the affected areas had moved away due to the intensification and impact of the gases.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

10 June 2009 Back to Top

On 14 June, OVSICORI-UNA reported that fumarolic activity from Turrialba had been observed all around the upper flanks of the active W crater. During the previous two months, the fumarolic activity was accompanied by widening of radial cracks (1.5 cm on average), 1-2 km tall gas-and-vapor plumes, and one sustained discrete seismic swarm. Temperatures of fumarolic vents in the lower parts of the crater were between 120 and 160 degrees Celsius. The temperature of summit cracks was 94 degrees Celsius. Dairy pastures and forests had been burned as far away as 3.5 km NW and W.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

1 October 2008 Back to Top

According to news articles, access to Turrialba Volcano National Park was closed on 30 September because the S and SE winds, typical for the time of year, were blowing toxic gases to the area of the park where visitors enter and view the volcano.

Sources: La Nacion

24 September 2008 Back to Top

OVSICORI-UNA reported that fieldwork on 23 September revealed severely impacted vegetation on Turrialba's flanks and inner caldera in areas only mildly affected during the previous three years of sustained degassing. Vegetation in the S and SE summit areas was severely burned and infrastructure was impacted during August and September. Along the flank, S of the W crater, plants were burned down to the soil. Trees in lower-altitude areas were yellowed and seared due to extreme acidification. Pastures and areas along canyons and depressions were also affected. OVSICORI-UNA recommended that precautions should be taken when carrying out activities in the affected areas.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

10 September 2008 Back to Top

OVSICORI-UNA reported that fumarolic activity and gas discharge in and to the W of Turrialba's central crater continued throughout August. Multiple fumaroles and sulfur deposition were noted in both the central and W craters. Fumarolic emissions on the S and SE flanks of the W crater continued to damage vegetation in that area.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

9 January 2008 Back to Top

OVSICORI-UNA reported that fumarolic activity and gas discharge in and to the W of Turrialba's central crater continued throughout December. Some fumaroles were 278 degrees C and exhibited sulfur sublimate deposition. Fumarolic plumes were visible from many kilometers away. Gases were emitted from cracks on the S external wall and burned vegetation was noted. Vegetation on the internal walls to the SW and towards the E was withered.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

5 December 2007 Back to Top

OVSICORI-UNA reported that members of the media and local communities observed a gas-and-steam plume from Turrialba that rose to an altitude greater than 5.3 km (17,400 ft) a.s.l. on 5 December. Fieldwork confirmed an unusual output of gas from several fumaroles along the S outer wall. Areas burned by acute acidification have extended in the last month. Pastures turned yellowish near the upper areas, and native and exotic tree species were impacted as well as birch tree patches along most drainages. Within the W crater, temperatures of fumaroles reached 280 degrees Celsius and native sulfur was present.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

5 September 2007 Back to Top

OVSICORI-UNA reported that fumarolic activity and gas discharge in and to the W of Turrialba's central crater continued throughout August. New points of gas discharge, small landslides, and accelerated vegetation die-off were noted from various locations within and around the crater. Fumaroles were active in almost all directions in the central crater; many exhibited sulfur deposits and those in the S, SE, and SW reached a temperature of 91 degrees C. Fumaroles at the bottom of the W crater reached 176 degrees C on 16 August. Small sulfur flows from a few of the fumaroles descended about 2 m from the emission point. Steam plumes from fumaroles on the W wall rose to an altitude of 3.8 km (12,500 ft) a.s.l.

New fumaroles appeared on the SW flank and N and NW of the central crater. Some of the fumaroles corresponded to two widening cracks, to the SW and NW of the W crater. Vegetation affected from gas and steam discharge and sulfur deposits were noted. People living on the N flank and from areas to the NW and W reported constant gas emissions from cracks in an area of about 20 by 50 meters, NW of the W crater.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

8 August 2007 Back to Top

OVSICORI reported that from mid-June through 8 August, several changes occurred at Turrialba, including opened fractures, spreading fumaroles, and an acute impact of gases on vegetation. Wide spreading of fumaroles on the upper edifice correlated with enhanced seismicity in mid-July. The principle fumarole in the bottom of the W crater reached 138 degrees C and produced a distinctive sound of a "high pressure valve" heard as far as 500 m away. The fumarole melted observable amounts of sulfur, a phenomenon not seen by the OVSICORI team in 25 years of continuous monitoring.

Multiple cracks associated with the expansion of the fumarolic areas around crater W were noted. A wide fumarolic field resided between two cracks about 100 m in length that propagated radially from the W and NW crater edges. Vegetation on the NW, W, and SW flanks appeared yellowish and dark brown, and patches of forest burned. Effects from the gases were observed in commercial farming areas.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

2 May 2007 Back to Top

On 6 May, scientists from OVSICORI declared a Low Alert Level for Turrialba based on rapid changes during the previous three months, and intensified their fieldwork and data collection efforts. During aerial observation in February 2007, trees looked yellowish due to sustained gas emissions from the W crater. Vegetation growth was noted in previously burned areas on the W and SW flanks near the summit. On 21 April, a hot area (40° C) was noted 1.5 km SW of the summit, at the base of the volcanic edifice, that coincides with the WSW-ENE-trending Ariete fault. On 2 May, two larger hot and fuming spots were documented along the same fault, about 200 m SW of the first area. The vapor plumes were spotted from several kilometers away, above the forest canopy. Heat destroyed vegetation in an approximately 300 square m area along the S fault's plane.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

18 October 2006 Back to Top

Fumarolic activity and gas discharge in and to the W of Turrialba's central crater continued throughout September. New points of gas discharge, small landslides, and accelerated vegetation die-off were noted from various locations within the crater.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

6 September 2006 Back to Top

Fumarolic activity and gas discharge in and to the W of Turrialba's central crater continued throughout August. On 30 August, scientists visiting the area noted that localized vegetation in and around the summit area had been heavily impacted by gases. Areas not affected by increased fumarolic activity in June 2005 had been singed by noxious gases, including a tree belt on the NW outer flank. Below the tree belt, farmers reported an intensification of gas odors. The shapes of the gas-scarred areas reflected prevailing wind directions.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date	Stop Date	Eruption Certainty	VEI	Evidence	Activity Area or Unit
[ 2010 Jul 24 ]	[ 2010 Aug 15 ]	Uncertain
2010 Jan 5	2010 Mar 7 (?)	Confirmed	2	Historical	SW crater
1866 Jan	1866 May 8	Confirmed	3	Historical	Central and SW summit craters
1864 Aug 17	1865 Mar	Confirmed	1	Historical	Central and SW summit craters
[ 1861 ]	[ Unknown ]	Uncertain
1855 May	Unknown	Confirmed	2	Historical
1853	Unknown	Confirmed	2	Historical
[ 1847 ]	[ Unknown ]	Uncertain
[ 1723 ]	[ Unknown ]	Uncertain	1
1350 (?)	Unknown	Confirmed		Radiocarbon (uncorrected)
640 ± 40 years	Unknown	Confirmed		Radiocarbon (corrected)
40 ± 50 years	Unknown	Confirmed	4	Radiocarbon (corrected)	Central summit crater
830 BCE ± 150 years	Unknown	Confirmed		Radiocarbon (corrected)
1120 BCE ± 200 years	Unknown	Confirmed		Tephrochronology
1420 BCE ± 300 years	Unknown	Confirmed		Radiocarbon (corrected)
7260 BCE ± 300 years	Unknown	Confirmed		Radiocarbon (corrected)	NE summit crater

Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive 3340-m-high Turrialba is exceeded in height only by Irazú, covers an area of 500 sq km, and is one of Costa Rica's most voluminous volcanoes. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m wide summit depression that is breached to the NE. Most activity at Turrialba originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred at Turrialba 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.