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Nicaragua’s Concepción volcano erupts 12 December 2009

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Concepción volcano in Nicaragua has erupted, with an explosion of gas and ashes that reached 150 metres into the air. The eruption took place at 08:40 local time (14:40 GMT) yesterday. Three villages located on the slopes of the volcano, Los Angeles, Esquipulas and San José del Sur, were affected by ashfall. There are no reports of injuries or serious disruption resulting from this eruption.

Concepción (summit elevation around 1700 metres) is one of two volcanoes making up the island of Ometepe in Lake Nicaragua: the other is Maderas, to which Concepción is connected by a narrow isthmus. Around 35,000 people live on Ometepe, which is one of Nicaragua’s most popular tourist destinations. Concepción is among the most active Nicaraguan volcanoes, with frequent explosive eruptions over the last century.

[Hat tip: commenter Rubén.]

News
Volcán Concepción lanza gases y cenizasEl Nuevo Diario, 11 December 2009
Volcán en lago nicaragüense lanza cenizas – Reuters América Latina, 11 December 2009
El volcán Concepción de Nicaragua registra explosiones y lanza gases y cenizas – EFE, 11 December 2009

Information
Global Volcanism Program: Concepción – summary information for Concepción (1404-12=)
Instituto Nicaragüense de Estudios Territoriales – INETER main page
INETER Comunicados Oficiales – INETER volcano bulletins (hopelessly out of date)

The Volcanism Blog

San Cristóbal’s ‘abnormal’ activity causes concern 5 October 2009

Posted by admin in activity reports, natural hazards, Nicaragua, San Cristóbal.
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‘The steady expulsion of gas and ash’ at San Cristóbal volcano in Nicaragua is causing concern for the surrounding population and the civil defence authorities, reports the Nicaraguan paper El Nuevo Diario: the volcano ‘has had three months of abnormal activity, although sometimes its behaviour is relatively calm’.

The inhabitants of communities affected by the volcano’s emissions – Chichigalpa, Posoltega, Chinandega and El Viejo – have expressed unease at the consequences for their health, and the local government has warned that the ‘fumes and ash could have dangerous consequences for the population’. The Instituto Nicaragüense de Estudios Territoriales (INETER) is constantly monitoring the volcano, which last erupted, on a small scale, a month ago.

News
Sigue actividad de fumarolas en el San CristóbalEl Nuevo Diario, 4 October 2009

Information
Global Volcanism Program: San Cristóbal – summary information for San Cristóbal (1404-02=)
Instituto Nicaragüense de Estudios Territoriales – INETER main page
INETER Comunicados Oficiales – INETER volcano bulletins (not up to date)

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

Eruption at San Cristóbal, Nicaragua 7 September 2009

Posted by admin in activity reports, eruptions, Nicaragua, San Cristóbal.
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The northernmost of Nicaragua’s active volcanoes, San Cristóbal, erupted yesterday. El Nuevo Diario reports that ‘eight explosions with emissions of brown ash and gas’ took place on Sunday afternoon. The explosions caused alarm, and an alert was issued for surrounding districts by the national civil defence service, but there are no reports of casualties or significant disruption. The local civil defense chief reported that the plume produced by the initial explosion reached a height of 700 metres above the crater, but the Instituto Nicaragüense de Estudios Territoriales (INETER) is quoted as reporting a height of 200 metres:

A statement from the Instituto Nicaragüense de Estudios Territoriales reports that at 1:50 this afternoon San Cristóbal volcano produced explosions of gas and ashes. The first explosion was detected by the seismic station located on the south-west slope of this volcano, and generated a column that reached an approximate altitude of 200 metres, remaining static because of the absence of wind. There then were four explosions of lesser intensity. According to reports from Defensa Civil personnel in the communities around the volcano, the activity continued until approximately 2:40 in the afternoon.

The INETER statement quoted by El Nuevo Diario does not seem as yet to be available on the volcanology section of the INETER website.

Washington VAAC reported ash at FL280 (i.e. 28000 feet/8500 metres altitude) following the eruption yesterday. The latest Washington ash advisories report no emissions.

Regular, relatively small-scale explosive eruptions are characteristic of San Cristóbal, which last erupted in November 2008. By the way, the Associated Press report wrongly states that the last eruption was in 2006. In fact there was a signficant VEI=2 eruption lasting from November 2005 to May 2006, then two eruptions in 2008, in June and November. It isn’t just AP that gets this wrong, however: Nicaragua’s La Prensa didn’t notice the 2008 eruptions either, and Univisión is busy headlining ‘tres años de inactividad’ when it should be ‘menos de un año de inactividad’.

News
8 explosiones en el San CristóbalEl Nuevo Diario, 6 September 2009
Volcán de Nicaragua lanza arena luego de tres años de inactividad – Univisión, 6 September 2009
Ofrece espectáculo la explosión de un volcán – Milenio.com, 6 September 2009
Nicaragua’s San Cristobal volcano spews ashes, gas – Associated Press, 7 September 2009
San Cristóbal lanza humo y arenaLa Prensa, 7 September 2009

Information
Global Volcanism Program: San Cristóbal – summary information for San Cristóbal (1404-02=)
Instituto Nicaragüense de Estudios Territoriales – INETER main page
INETER Comunicados Oficiales – INETER volcano bulletins (not up to date)

The Volcanism Blog

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

Posted by admin in activity reports, Costa Rica, natural hazards, Turrialba.
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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

El Salvador: Chaparrastique/San Miguel calming down? 13 July 2009

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San Miguel from the north, 22 February 2005. Image Courtesy Servicio Nacional de Estudios Territoriales (SNET).
San Miguel from the north, 22 February 2005. Courtesy Servicio Nacional de Estudios Territoriales (SNET). [source]

El Salvador’s geological service, the Servicio Nacional de Estudios Territoriales (SNET), issued a special bulletin on 10 July reporting that the seismic activity recently observed at San Miguel volcano (known locally as Chaparrastique) was ‘showing a tendency towards decline’:

Yesterday, 9 July 2009, the microseismicity at the volcano declined to a daily average of 147 units RSAM. Today [10 July 2009], up to 15:00, the seismic stations have registered a daily average of 116 units. If this is compared to the values of previous days it can be seen that there is a tendency towards decline. It is important to note that the seismic energy of the volcano normally fluctuates between 30 and 50 units RSAM.

SNET is continuing to monitor the situation closely, and for the moment security measures, including a 2-kilometre-radius exclusion zone around the summit of the volcano, are remaining in force.

News
Sigue disminuyendo sismicidad en volcán ChaparrastiqueDiario La Página, 11 July 2009

Information
Global Volcanism Program: San Miguel – summary information for San Miguel/Chaparristique (1403-10=)
Servicio Nacional de Estudios Territoriales (SNET) – Salvadorean national geological service

The Volcanism Blog

Increased seismicity at San Miguel volcano (Chaparrastique), El Salvador 7 July 2009

Posted by admin in activity reports, El Salvador, San Miguel.
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San Miguel volcano, also known locally as Chaparrastique, is situated in the east of El Salvador and is a mere 15 km away from the city of San Miguel (population more than 200,000). It is one of El Salvador’s most active volcanoes, with a record of frequent eruptions since the early sixteenth century.

There are now reports of increased seismic activity, in the form of microquakes, at the volcano. The Salvadorean geological service, the Servicio Nacional de Estudios Territoriales (SNET), reports in a special bulletin that there has been an ‘increase in microseismicity [microsismicidad] at Chaparrastique volcano beginning at 03:00 on 6 July 2009′ which is reflected in the RSAM signal which has been fluctuating at 700-1300 units, well above the normal hourly average of 30-50 units RSAM. Such ‘microseismicity’ has been associated in the past with other manifestations of volcanic activity, and is caused by the heating of water within the volcano. The SNET bulletin explains:

The microseismicity is associated with the pressure of [water] vapour which causes the volcanic structure to vibrate, and which is caused by the heating and evaporation of rainwater which infiltrates and moves through the strata of the volcano, increasing its internal pressure.

A 2-kilometre-radius ‘security zone’ has been imposed around the volcano, with local residents and tourists being advised to keep away while monitoring of the volcano continues.

News
Reportan major actividad del volcán de San MiguelEl Diario del Hoy, 6 July 2009
Volcán sube los niveles de actividadEl Diario del Hoy, 6 July 2009
Volcán Chaparrastique de El Salvador incrementa su actividad microsísmica – Terra.com, 7 July 2009
Vigilan volcán salvadoreño por actividad microsísmica – Univisión, 7 July 2009

Information
Global Volcanism Program: San Miguel – summary information for San Miguel/Chaparristique (1403-10=)
Servicio Nacional de Estudios Territoriales (SNET) – Salvadorean national geological service

The Volcanism Blog

Turrialba’s unwelcome emissions 26 April 2009

Posted by admin in activity reports, Costa Rica, natural hazards, Turrialba.
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Turrialba volcano in Costa Rica, a massive 3340-metre high stratovolcano, has been quiescent since a series of explosive eruptions in the mid-nineteenth century. The last eruption sequence lasted from August 1864 to February 1866, ending with a VEI=3 event producing pyroclastic flows, lahars and thick ashfall. There have been no further explosive eruptions but seismicity began to increase in the late 1990s and fumarolic activity became more pronounced in the early 2000s. The threat of renewed explosive activity remains.*

The main hazard Turrialba is presenting at the moment, however, is a non-eruptive one. As part of the generalized upswing in activity over the past few years, levels of sulphur dioxide in the volcano’s emissions increased greatly, reports the USGS, from around 140 tonnes/day in late 2007 to 1100-2000 tonnes/day in summer 2008. The most recently available figures on Turrialba’s SO2 flux come from the 4th Ticosonde Workshop (PDF) held at Costa Rica’s Universidad Nacional on 26 March 2009: a presentation by Dr Sebastián Miranda of the Observatorio Vulcanológico y Sismológico de Costa Rica (Oviscori) reported that emissions have recently shown a decline, with an average SO2 flux for the period December 2008 to February 2009 of 250 tonnes/day.

This recent decline notwithstanding, Turrialba’s SO2 emissions have had a dramatic effect on local vegetation. Sulphur dioxide is damaging to plants in high concentrations, but the effects of long exposure to even relatively low concentrations are potentially much more destructive. causing growth reduction, burning and damage to foliage (foliar necrosis) and yellowing due to a lack of chlorophyll (chlorosis). Vegetation situated below a persistent SO2-rich volcanic plume will be severely affected, while acid rain generated by the SO2 concentrations may spread the damage even further.

An article in the Costa Rican newspaper La Nación today makes it clear how serious the problem is. Headed ‘Daños por volcán Turrialba ganan terreno este año’ (‘Damage from Turrialba volcano gains ground this year’) it describes the severe problems the persistent exposure to the volcanic emissions has caused. Javier Coto, who farms land near Turrialba, reports that ‘today we have only dry grass. Here everything is bad. The barbed wire fences crumble and the iron roofing rots away’. Workers at a nearby dairy wear masks to help them cope with the ‘almost unbearable’ sulphurous smell of the gases, and the burning of pastures affects milk production. The area affected by Turrialba’s emissions has expanded, according to Ovsicori scientists, increasing the impact on local agriculture:

In the areas closer to the mountain, the damage caused by the burning ‘is irreversible’, says scientist Eliécer Duarte of Oviscori. ‘In the area of the summit of Cerro San Juan (near the crater of Turrialba) all the vegetation is totally dead. Shrubs that have shown little effect on other occasions … are today completely burned on their surface and into the wood. Small plants, shrubs and trees of low habit are covered with a fine coating of sulphur.’

Wind patterns and the effects of the increase in emissions are responsible for the greater degree of damage this year, say experts from Ovsicori.

Meanwhile, the most recent studies of Turrialba by the Costa Rica National Seismological Network indicate increased seismicity, with a growth in the numbers of hybrid and superficial volcano-tectonic earthquakes being recorded, El Azucarero reported this week.

* For a clear overview of Turrialba’s eruptive history and hazard potential, see M. Reagan, E. Duarte, G. J. Soto & E. Fernández, ‘The eruptive history of Turrialba volcano, Costa Rica, and potential hazards from future eruptions’, in William I. Rose, Gregg J. S. Bluth, Michael J. Carr, John W. Ewert, Lina C. Patino & James W. Vallance, Volcanic Hazards in Central America (Boulder, CO: Geological Society of America, 2006), pp. 235-57.

News
Daños por volcán Turrialba ganan terreno este añoLa Nación, 26 April 2009
Geólogos detectan incremento sísmico en el Volcán TurrialbaEl Azucarero, 24 April 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

Arenal: increased activity causes concern 4 April 2009

Posted by admin in activity reports, Arenal, Costa Rica, volcano monitoring.
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Arenal at night, photographed 7 April 2006 by Scott Robinson (Creative Commons license)

Costa Rica’s Comisión Nacional de Emergencias (CNE) is stepping up monitoring of Arenal volcano following an increase in seismic activity over the last month. The national seismological monitoring network (Red Sismológica Nacional) reports that 45 earthquakes were recorded during March, compared with ’4 or 5′ in February. Seismologist Guillermo Alvarado is quoted in the Mexican newspaper El Financiero as saying that similar behaviour to that recorded in March preceded significant eruptive activity in 1975, 1993, 2000 and 2001. The CNE will be co-ordinating measures to ensure that tourists visiting Arenal and its surroundings over the Easter holidays are kept to safe areas and informed about potential dangers.

Note the irresponsible headline on the English-language Inside Costa Rica story: ‘Experts predicting major activity from Arenal volcano’. They are doing nothing of the sort: volcanologists and seismologists never predict, they only forecast, and in this case they are not even doing that, they are just drawing attention to a pattern of behaviour that has in the past been associated with eruptive activity and working with the authorities to ensure that warnings are issued and prudent precautions are taken. The Inside Costa Rica story itself contradicts its own headline by reporting that Eliécer Duarte of the Observatorio Vulcanológico y Sismológico de Costa Rica ‘said that the volcano has maintained sustained activity for the last 40 years and that, although there will be new flows and related activities, it does not necessarily mean a precursor to “major” cycles and the basis for the predictions’ — the ‘predictions’ none of the experts are making, because there is no basis for them.

Image: Arenal, photographed 7 April 2006 by Scott Robinson (Creative Commons license). [source]

News
Experts predicting major activity from Arenal volcanoInside Costa Rica, 2 April 2009
Vigilan en Costa Rica al volcán ArenalEl Financiero, 3 April 2009
CNE aumenta vigilancia en ArenalLa Nación, 3 April 2009

Information
Global Volcanism Program: Arenal – summary information for Arenal (1405-033)
Observatorio Vulcanológico y Sismológico de Costa Rica – main page for Ovsicori

The Volcanism Blog

Ashfall from Fuego and Santiaguito 17 March 2009

Posted by admin in activity reports, Fuego, Guatemala, natural hazards, Santa María.
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Guatemala’s Prensa Libre newspaper reported yesterday that Fuego and Santiaguito volcanoes (the Santiaguito lava dome complex is part of Santa María volcano) are producing ‘large quantities of ash’, and that the aviation and emergency authorities have been alerted. The report says that the two volcanoes were producing powerful explosions and erupting incandescent material and steam, with ashfall being reported up to 8-12km distant. In the village of Sangre de Cristo, near Fuego, drinking water and food have been contaminated by ash.

Washington VAAC has no current volcanic ash advisories for Fuego, although emissions were reported 12-13 March 2009. An ash cloud was reported from Santa María on 15 March. The Instituto de Sismología, Vulcanología y Meteorología of Guatemala (Insivumeh) has been reporting light ashfall from Fuego and light to moderate ashfall from Santiaguito.

The Santiaguito dome complex has been almost continuously active since its appearance in 1922, within the crater left by the huge eruption (VEI=6?) of Santa María in 1902.

News
Volcanes de Fuego y Santiaguito lanzan grandes cantidades de cenizaPrensa Libre, 16 March 2009

Information
Global Volcanism Program: Fuego – summary information for Fuego (1402-09=)
Global Volcanism Program: Santa María – summary information for Santa María (1402-03=)
Instituto Nacional de Sismologia, Vulcanología, Meteorología e Hidrologia – main page for Guatemala’s volcanological authority

The Volcanism Blog

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