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UFO alert as volcano-visiting aliens caught on camera at Turrialba 7 February 2010

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A sharp-eyed Costa Rican has spotted a UFO caught by the OVSICORI webcam recently installed at the summit of Turrialba, reports La Prensa Libre. The sighting happened on 27 January and has been verified by ‘an expert on UFOs’ (so that’s alright then). Aliens have visited Costa Rica’s volcanoes before: here they are buzzing Arenal in 2007.

(UFOs in Spanish are OVNIs: ‘Objetos Voladores No Identificados’.)

The Volcanism Blog

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Turrialba calmer, but helium emissions create a stir 3 February 2010

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Turrialba, which erupted on a small scale at the beginning of January, has returned to a state of ‘passive degassing’ similar to that which pertained before the eruption, according to reports from Costa Rica. However, Ovsicori experts have warned that although activity has declined low intensity earthquakes continue, the volcano remains active and people should not be complacent. The Comisión Nacional de Emergencias (CNE) has revised the alert levels currently applied to the area surrounding the volcano, with Yellow Alert now applying to a 2 km radius zone around the volcano and Green Alert to areas beyond that limit (CNE news release: Alerta Verde y Alerta Amarilla ante Actividad Volcánica).

Levels of gas emission from Turrialba have fallen since the eruption but this volcano is a persistent and unpleasant degasser, and this aspect of its activity continues. In particular, the appearance of large amounts of helium in Turrialba’s emissions has been attracting the attention of the experts. There’s nothing official about this yet from Ovsicori, but the Costa Rican newspaper La Nación reports that ‘the volcanologists could not believe what was happening’ when Jorge Andres Díaz, a physicist and gas measurement specialist working for the Comisión Nacional de Emergencias reported that measurements taken on 19 January 2010 indicated there was 30 ppm (parts per million) of helium in Turrialba’s emissions:

For the volcanologists of the National Seismological Network and Ovsicori, that figure was much too ‘high’, because normally helium at the volcano fluctuates between 2 and 8 ppm. ‘That would be way too much’, says Raúl Mora, volcanologist at the [National Seismological] Network.

The volcanologists and Díaz apparently got into a discussion lasting several hours about this at the CNE headquarters yesterday, according to La Nación.

However, the presence of high proportions of helium in gas emissions from Turrialba was noted back in April 2008, when it was interpreted as being the result of magma build-up within the volcano. Measurements taken in March 2008, also by Díaz, indicated helium levels of 80 ppm. At that time, Ovsicori reported the normal level of helium for Turrialba as 25 ppm, which would make a possible level of 30 ppm now a bit less of a leap (an earlier report in the Tico Times has Díaz reporting levels of 20 ppm). In any case, the presence of elevated helium levels in Turrialba’s emissions is an indicator that fresh magma is being intruded into the volcanic system.

(Useful information about the significance of magmatic helium can be found in ‘Helium discharge at Mammoth Mountain Fumarole’, from the USGS’s Long Valley Volcano Observatory.)

For all our coverage of Turrialba: Turrialba « The Volcanism Blog.

News
Helium also rising from Costa Rica’s Turrialba volcanoTico Times, 21 January 2010
Medición de helio generó intenso debateLa Nación, 31 January 2010
El Turrialba lanza menos gases pero siguen los sismosLa Nación, 30 January 2010
CNE outlines risk areas around Turrialba volcano as gas still spewsTico Times, 1 February 2010

Information
Global Volcanism Program: Turrialba – summary information for Turrialba (1405-07=)
Observatorio Vulcanológico y Sismológico de Costa Rica – Ovsicori website
Volcán Turrialba – information from Ovsicori
Turrialba webcam – Ovsicori’s webcam at Turrialba’s summit
Monitoreo Volcanico (Red Sismológica Nacional) – volcano monitoring updates from the Costa Rican national seismological network

The Volcanism Blog

Unrest at Turrialba: new NASA image, and an overflight 27 January 2010

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Unrest at Turrialba volcano, Costa Rica, 21 January 2010 (NASA EO-1 ALI image)

The image above, from the NASA Earth Observatory, shows ongoing activity at Turrialba volcano, Costa Rica, captured by the Advanced Land Imager (ALI) aboard NASA’s Earth Observing-1 (EO-1) satellite on 21 January 2010. The damage caused to vegetation to the west of the volcano’s summit by acidic gas emissions is clearly visible. Hazy grey-blue fumes can be seen drifting north from the active summit crater, which is the westernmost of Turrialba’s three craters.

The current cycle of activity at Turrialba began in 2007 with an increase in fumarolic emissions and the opening of cracks in the summit area. Turrialba’s gas emissions caused severe problems for local agricultural communities during 2008 and 2009 because of acid burning of vegetation: crops have been damaged, and pasture for livestock has also been affected. On 5 January 2010 there was a small eruption, the first since 1866. Gas emissions fell in the aftermath of the eruption, but have increased again subsequently.

Turrialba volcano from the NE, 20 January 2010 (E. Duarte, OVSICORI-UNA)
View of Turrialba volcano from the NE, showing the plume being produced from the new cavity opened by the recent activity. Photograph taken by E. Duarte on 20 January 2010 (OVSICORI-UNA).

On 20 January 2010 an overflight of Turrialba took place (OVSICORI report PDF here) which reported a ‘revitalization of the column of gas and steam with suspended particles’. The photograph above was taken during this overflight. A sustained emission was reported on that day, with a thick, dark plume from the summit moving WNW, the strong wind preventing the plume from rising much above the altitude of the volcano. Some light ashfall was reported in areas near the volcano. ‘Although the transport and distribution of volcanic particles (old ash) is a new occurrence for this eruptive period of Turrialba volcano’, notes the report, ‘the minimal quantity carried this morning could be the first of much more in the near future’ as material eroded from the internal walls of the active conduit is carried up into the plume.

For all our coverage of Turrialba: Turrialba « The Volcanism Blog.

Information
Global Volcanism Program: Turrialba – summary information for Turrialba (1405-07=)
Observatorio Vulcanológico y Sismológico de Costa Rica – Ovsicori website
Volcán Turrialba – information from Ovsicori
Turrialba webcam – Ovsicori’s webcam at Turrialba’s summit
Monitoreo Volcanico (Red Sismológica Nacional) – volcano monitoring updates from the Costa Rican national seismological network

The Volcanism Blog

A webcam for Turrialba 26 January 2010

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Costa Rica’s Observatorio Vulcanológico y Sismológico de Costa Rica (Ovsicori) now has a webcam for currently restless Turrialba volcano. The camera is currently in the testing stage, and the image refreshes every 10 seconds:

http://www.ovsicori.una.ac.cr/videoturri.html

Still with Turrialba, the NASA Earth Observatory has just published a great new image of the volcano, showing emissions from the summit and the damage that gas emissions have been doing to downwind vegetation. We’ll be posting more about this image, and about Turrialba generally, later today.

The Volcanism Blog

Turrialba bulletin, 4-8 January 2010 11 January 2010

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The Observatorio Vulcanológico y Sismológico de Costa Rica (Ovsicori) has released a bulletin covering activity at Turrialba volcano between 4 and 8 January 2010 (PDF), including the eruption of 5 January 2010, which is described as follows:

Around 14:00 on 5 January 2010 ashfall originating from the western crater of Turrialba volcano was reported in several localities around the volcano (La Central, La Pastora, La Esperanza, among others) and in more distant locations such as the Irazú Volcano National Park, Aguacaliente de Cartago, Tres Ríos, Curridabat and Desamparados. This eruption, which is another manifestation of the degassing of the volcano, consitutes the first eruption of ash from Turrialba in many decades.

The bulletin notes that during 2009 seismic activity at Turrialba was characterized by the ‘almost constant occurrence of LP [long period] type earthquakes’ associated with gas (mainly water vapour) movements within the volcano, and that this activity continued into the first few days of 2010 with an average of 10 earthquakes per day. This pattern of behaviour changed on 4 January 2010:

On 4 January at 10:57 (local time) there was a phreatic explosion (caused by the decompression of steam at high temperatures) of a large scale at the volcano (greater than those occurring during 2009) followed by another three explosions of lesser magnitude at an interval of 10 minutes. These explosions were produced by the opening of ducts for the escape of pressurized gas. The explosions were followed by a tremor of large amplitude that was maintained for more than 45 minutes. The tremors resulted from the movement of fluids through restricted ducts, in this case associated with the expulsion of gas and ash or fine particles swept along by the expelled gas. The tremor persisted but its amplitude decreased towards 15:20 as several smaller explosions took place followed by almost continuous tremor, sometimes spasmodic, reaching large amplitudes at 23:30 on 4 January and 10:45 on 5 January. From 15:30 on 5 January the tremor is recorded continuously and at low amplitudes.

This low-amplitude tremor continued until 16:58 on 8 January; since that time the tremor has ended and the volcano has returned to the same LP type earthquakes that were recorded before 4 January, ‘so it is possible to be sure that activity at the volcano has returned to the levels of before the phreatic eruption’.

Ovsicori scientists carried out a field visit on 6 January to assess ashfall and collect ash samples. They found ‘a very thin layer of ash’, not uniform in distribution, across and area between 8 km and 15 km WSW of the volcano. Analysis of the ash revealed that ‘the ashes erupted by Turrialba volcano between 5 and 6 January are almost [pH] neutral, i.e. of a nature between very slightly acidic (mildly corrosive) and very slightly alkaline (mildly caustic)’. The low acidity of the lava ‘suggests that so far there has been no involvement of lava in the ash eruptions or additional inputs of new magmatic gases’.

The bulletin offers the following interpretation of current activity at Turrialba, and the prospects for the next few days and weeks:

The eruptive activity that began on 5 January represents a process at a superficial level in the volcano, consisting of the rapid heating and vaporization of a body of subterranean water followed by sudden decompression through the fracture system of Turrialba. The discharge of steam and gases through the fumaroles on this occasion has had much more vigorous results than those observed in previous years. The heat source is provided by the intrusion of a magmatic body at depth … The absence of juvenile magmatic material in the recently erupted ash and its pH indicate that the groundwater has not come into contact with the magma intruded at depth but has been mainly heated by the conduction of heat through the rocks within the volcano.

In summary, at present there are no characteristic signs indicating the presence of magma at shallow levels in the volcano, so the occurrence of an eruption of magmatic nature in the near future (the next few days or weeks) can be ruled out. However, it is not possible to rule out the occurrence of new phreatic events (similar to those seen in recent days).

For all our coverage of Turrialba: Turrialba « The Volcanism Blog.

Information
Global Volcanism Program: Turrialba – summary information for Turrialba (1405-07=)
Observatorio Vulcanológico y Sismológico de Costa Rica – Ovsicori website
Volcán Turrialba – information from Ovsicori
Monitoreo Volcanico (Red Sismológica Nacional) – volcano monitoring updates from the Costa Rican national seismological network

The Volcanism Blog

Christmas Day eruption at Poás captured on video 6 January 2010

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You may recall our report of a phreatomagmatic display that Poás volcano in Costa Rica put on to celebrate Christmas Day: well, you can now see a video of the event – ‘Central Georgia couple captures video of erupting volcano’ (also at YouTube).

There is also an interview with tourist Tom Wellman, who made the video. Strange remark 1: ‘this type of volcano doesn’t put out liquid lava. Instead it puts out a dry lava with steam’. Strange remark 2: ‘Tom says that this is the first time in the history of Costa Rica that anyone has recorded video of an erupting volcano’. Not really, try this.

Costa Rican newspaper La Nación has some nice still pictures of the Poás eruption, taken by Kristina Kremer.

UPDATE 11 February 2010. Tom Wellman has provided some clarification regarding his video: please see his comment below.

[Hat tip: Damon Hynes via Eruptions.]

The Volcanism Blog

Costa Rica: eruption at Turrialba 6 January 2010

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There have been signs of increased activity at Turrialba volcano in Costa Rica for some time – a rise in gas emissions, temperature increases around the crater, new cracks in the summit area – and now comes news that there has been a small eruption, the first at Turrialba since 1866. The Costa Rican geological service Ovsicori have issued a bulletin on the eruption (PDF), which reports as follows:

On 5 January 2010 at 14:48 local time an inhabitant of the La Central area located to the south-west of Turrialba volcano reported hearing a strong eruption of Turrialba, much later people living near the volcano reported ashfall. Also, officials of the Parque Nacional Volcán Irazú reported the presence of ash in vehicles parked in the car park inside the national park. Additionally, residents of Turrialba, Tres Ríos and owners of properties on the slopes of Turrialba volcano reported ashfall.

From mid-December 2009 until 4 January 2010, LP-type earthquakes (low frequency) had been predominantly registered, with a significant decrease of volcanic tremor. On 4 January 2010 there was a significant increase in volcanic tremor, both in duration of registration and in the amplitude of the signal. Coinciding with the increase in the recording of tremor there was a significant decrease in LP-type earthquakes. In the early hours of Wednesday 6 January an OVSICORI-UNA team will go to the area to make observations and collect data and information to carry out relevant studies.

A green (preventative) alert was issued by the authorities for the area around Turrialba, and about 20 people were evacuated from the volcano’s slopes.

The volcanic deposits reported as falling in villages to the south-west of Turrialba up to 3 km from the crater were described by Ovsicori as ‘white powder’. Eliécer Duarte of Ovsicori told La Nación that ‘this is not ash. Ash is black, glassy, sharp, and causes much damage’. Duarte said that the material produced by this eruption could represent ‘a stage preceding the eruption of juvenile material’, indicating that the volcano ‘now has the capacity to erupt much heavier material into the atmosphere’. The suggestion is that the material erupted so far is pulverized old rock rather than fresh magmatic material. However, local inhabitants have insisted that the material is ‘black and sandy. A Red Cross official in one affected village has reported sulphurous smells and ashfall, and says that there are ‘black spots’ on the plastic sheeting covering crops in local plantations. The National Emergencies Commission (CNE), meanwhile, describes Turrialba’s activity in a press release as ‘a minor ash eruption with a little acid rain’.

Overall, the Costa Rican authorities seem to be regarding this event as a minor eruption, but a possible precursor of larger-scale activity to come.

For all our coverage of Turrialba: Turrialba « The Volcanism Blog.

News
Ovsicori confirma erupción de sedimento blanco del TurrialbaLa Nación, 5 January 2010
Alerta en Costa Rica por erupción de ceniza en el volcán Turrialba – EFE, 5 January 2010
Vecinos insisten en que cayó ceniza en poblados de Oreamuno y CartagoLa Nación, 5 January 2010
Tras 145 años, despierta el volcán TurrialbaEl Informador, 5 January 2010
Costa Rican volcano erupts after long silence – Reuters, 5 January 2010
Families evacuate Turrialba area as volcano acts upTico Times, 5 January 2010

Information
Global Volcanism Program: Turrialba – summary information for Turrialba (1405-07=)
Observatorio Vulcanológico y Sismológico de Costa Rica – Ovsicori website
Volcán Turrialba – information from Ovsicori
Monitoreo Volcanico (Red Sismológica Nacional) – volcano monitoring updates from the Costa Rican national seismological network

The Volcanism Blog

Turrialba more active, emissions increase 13 October 2009

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Turrialba volcano in Costa Rica is not a good neighbour: its sulphur dioxide emissions spread across the adjacent countryside, particularly to the west, damaging local vegetation and ruining the local agricultural economy. Costa Rica’s Teletica news channel has been reporting on the effects of recent increases in Turrialba’s emissions, now running at between 700 and 2000 tonnes/day: ‘The green vegetation that covered the volcano has been replaced by a bright yellow, and the trees have been turned into skeletons’, local schoolchildren are having to wear breathing masks to protect them from the unhealthy effects of the gases, and even the equipment used by scientists to monitor the volcano has been damaged by accelerated corrosion (‘Turrialba volcano’s activity is a threat to surrounding villages’). Vegetation around the volcano may not recover from the damage for 20 years, and the effects on local agricultural communities have been severe: arable and livestock farmers have been forced out of business by the effects of Turrialba’s emissions, and local milk production has declined (‘Environmental damage caused by Turrialba volcano destroyes vegetation and agricultural production’). Some nearby villages have been abandoned by their inhabitants because of the effects of Turrialba’s sulphur dioxide.

Recent field investigations by Costa Rica’s geological authority OVSICORI have revealed further signs of increased activity at Turrialba: increased sulphur deposition within the active western crater and the appearance of new fissures and the widening of existing cracks on the southern rim of the west crater and low down on the north-western flank of the volcano. These new cracks are emitting gas-and-vapour fumes, adding to the emissions problem. A news report from Costa Rica’s Columbia radio station on 7 October, headed ‘Turrialba volcano is more active than ever’, says OVSICORI have also found temperature increases in the west crater, in addition to cracks and sustained emissions producing a white gas column.

Meanwhile, La Nación reports that the Costa Rican national seismological network (Red Sismológica Nacional) has registered ‘a significant fall in the number of earthquakes’ at Turrialba – but that seismicity may be on the rise at Rincón de la Vieja volcano, where ‘a significant number of minor earthquakes’ have been detected.

News
El Volcán Turrialba está más activo que nunca – Columbia, 7 October 2009
Actividad del volcán Turrialba amenaza a poblaciones cercanas – Teletica, 7 October 2009
Daño ambiental provocado por volcán Turrialba acaba con vegetación en montañas y producción agrícola – Teletica, 8 October 2009
Vulcanólogos detectan sismos leves en Rincón de la ViejaLa Nación, 12 October 2009

Information
Global Volcanism Program: Turrialba – summary information for Turrialba (1405-07=)
Global Volcanism Program: Rincón de la Vieja – summary information for Rincón de la Vieja (1405-02=)
Observatorio Vulcanológico y Sismológico de Costa Rica – Ovsicori website
Volcán Turrialba – information from Ovsicori
Monitoreo Volcanico (Red Sismológica Nacional) – volcano monitoring updates from the Costa Rican national seismological network

The Volcanism Blog

Phreatic eruption at Poás, Costa Rica 21 September 2009

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Poás volcano produced a phreatic eruption on Friday morning, 18 September, reports Costa Rican newspaper La Nación. The eruption projected water and sediment to a height of 300 metres above the surface of the crater lake. It is the northern of the volcano’s two summmit crater lakes, Lago Caliente, which is the site of frequent phreatic eruptions; the most recent, a smaller event, was in January this year.

The report also mentions that scientists visiting the summit of Poás have found burning sulphur on the north wall of the crater lake, the first time this phenomenon has been seen since 1994. Recent high temperatures and low rainfall have reduced the water volume in the highly acidic lake, and degassing from the crater has intensified with the gas plume – ‘bright yellow’ in certain areas – reaching 400 metres in height when measured on 16 September. The sulphurous plume may present a hazard for visitors to the volcano, which is one of Costa Rica’s most popular tourist attractions.

News
Volcán Poás hizo erupción de agua y sedimentosLa Nación, 20 September 2009

Information
Global Volcanism Program: Poás – information about Poás (1405-04=)
Observatorio Vulcanológico y Sismológico de Costa Rica – Volcanological and Seismological observatory of Costa Rica (OVSICORI)
Volcán Poás – profile of Poás volcano from OVSICORI

The Volcanism Blog

Turrialba: increased activity reported, some homes abandoned 2 September 2009

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The Costa Rican volcano Turrialba is showing an increase in activity, reports Univisión today (quoting an Associated Press report). The report quotes Observatorio Vulcanológico y Sismológico de Costa Rica (Ovsicori) volcanologist Eliécer Duarte as saying that the volcano is in a ‘gaseous phase’ which precedes the ‘presence of solids’, with the latter represening ‘much more dramatic activity’. An Ovsicori field trip to Turrialba last week confirmed that new cracks and fumaroles had appeared on the volcano’s flanks.

Some villagers and farmers around the volcano, alarmed at its increased activity, have decided to leave their homes, reports Costa Rica’s La Nación. Many local inhabitants are particularly concerned at the damage being done to vegetation by Turrialba’s SO2-laden, acidic and very nasty emissions, which burn trees, shrubs and grasslands around the volcano and are seriously damaging local agriculture:

Some people even evacuated their dairy cattle, because of the loss of grassland, the toxicity of the gases emanating from the volcano and the fear that more animals will die because of the new vents that have appeared low down [on the volcano].

There was increased activity at Turrialba earlier this summer, and roads through the surrounding National Park were closed to visitors as a precaution.

News
Costa Rica: alertan incremento de actividad en volcán – Univisión, 2 September 2009
Vecinos dejan casas por volcán TurrialbaLa Nación, 2 September 2009

Information
Global Volcanism Program: Turrialba – summary information for Turrialba (1405-07=)
Observatorio Vulcanológico y Sismológico de Costa Rica – Ovsicori website
Volcán Turrialba – information from Ovsicori

The Volcanism Blog