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Two explosions as Nicaragua’s San Cristóbal clears its throat 5 July 2010

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Dos grandes “eructos” de volcán San Cristóbal‘ says the headline in Nicaragua’s El Nuevo Diario newspaper: ‘two big “belches” from San Cristóbal volcano’. The eructations in question happened on Friday afternoon, 2 July 2010: two explosions from the summit crater at about 13:05 and 13:10 ejected pyroclastic material, ‘including rocks with a diameter of up to ten metres’, which caused fires in nearby grasslands. A ‘mushroom cloud’ of ash was produced by the second explosion, and light ashfall occurred in villages NW of the volcano. No damage or injuries were reported. An emergency plan was activated for the areas around the volcano, but there were no further signs of activity over the weekend. The Instituto Nicaragüense de Estudios Territoriales (INETER) described Friday’s activity as ‘normal degassing’.

News
Dos grandes “eructos” de volcán San CristóbalEl Nuevo Diario, 4 July 2010

Information
Global Volcanism Program: San Cristóbal – summary information for San Cristóbal (1404-02=)
Instituto Nicaragüense de Estudios Territoriales – INETER main page

The Volcanism Blog

Marsili seamount: tsunami threat for Southern Italy? 30 March 2010

Posted by admin in Italy, Marsili, natural hazards, submarine volcanism, volcano monitoring, volcanoes.
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Mount Marsili is a 3000-metre high seamount beneath the Tyrrhenian Sea, 150 km south-west of Naples. Marsili is active and recent research has indicated signs of restlessness (see this 2006 paper in PDF), although the risks of any dangerous eruptive activity are very slight). In an interview with the Italian newspaper Corriere della Sera, the director of the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Dr Enzo Boschi, has reminded everyone that Marsili is active and that there is a potential threat of an eruption/collapse generating a tsunami that would threaten Southern Italy:

It could happen tomorrow. The latest research says that the volcanic edifice is not strong and its walls are fragile. Furthermore we have measured the magma chamber that has formed in recent years and it is of large dimensions. All this tells us that the volcano is active and could erupt unexpectedly.

According to the article, observations indicate that hydrothermal emissions from vents around Marsili have become more intense recently, and evidence of landslides discovered by the oceanographic research vessel Urania last February ‘indicate an instability impossible to ignore’. Dr Boschi warns that a flank collapse at Marsili ‘would displace millions of cubic metres of material, which would be capable of generating a wave of great power’. Marsili is currently unmonitored, observes Dr Boschi: ‘A network of seismometers should be installed around the edifice, connected on land to a volcano monitoring centre. But this is beyond the budget’.

And it seems reasonable to suggest that the budget is what this article is actually all about. Despite the new attention this story will bring to Marsili as it gets cut-and-pasted around the web, there is nothing substantially new here, as Aldo Piombino notes in a very comprehensive post published on his blog today. No new activity lies behind this report, and nor has the potential threat, such as it is, changed in any way. The novelty, he observes, is in public attention being drawn to the need to monitor Marsili, which has been invisible in every sense as far as the Italian public is concerned.

Undersea volcanoes tend to be out of sight and out of mind. Writing in 2008, Aldo Piombino called Marsili ‘one of the least-known of the huge volcanic systems of Europe’, and argued that more attention must be paid to this active and potentially very destructive underwater giant:

It is statistically very unlikely that in our lifetimes we will see an explosion of Marsili, and even less likely that we will see a tsunami caused by a landslide on its flanks, but it is to be hoped that it will be placed under close seismic and geochemical surveillance, as with other active Italian volcanoes. I believe that it is necessary for civil protection and for science that one of the largest volcanoes in Europe is better understood.

Boris Behncke of the INGV discussed Marsili’s activity in the course of his Q&A on Dr Klemetti’s Eruptions blog last year, but also remarked that monitoring Marsili was not a priority for the INGV [UPDATE: in fact that is not what Boris meant. He meant that Marsili has not been a priority for the Italian authorities, Civil Defence, and the Italian public, rather than the INGV - see his comment at Eruptions]. Dr Boschi’s comments today would seem to indicate that that has changed. Aldo Piombino observes today that the technology is available within the INGV to monitor Marsili directly from the seabed using new broadband seismometers transmitting to land-based monitoring stations, and supports Dr Boschi’s call for full monitoring of the volcano. But that cannot happen without money, which is more likely to be forthcoming if the potential (and real but, it must be emphasized again, very remote) dangers of a tsunami-generating collapse at Marsili are stressed – hence the Corriere della Sera article.

So, it seems that a push has begun within Italian volcanology to get Marsili wired up for continuous and comprehensive monitoring. Let us hope it succeeds.

UPDATE 30 March 2010: Dr Erik Klemetti has more on Marsili at Eruptions, and Boris Behncke, himself of the INGV (Dr Boschi is Boris’s boss), has an illuminating comment here.

News
Torna a far paura il vulcano sommerso nel TirrenoCorriere della Sera, 29 March 2010
Undersea volcano threatens southern Italy: report – AFP, 29 March 2010
Il Monte Marsili, un gigantesco vulcano nascosto dalle profondità del Mar Tirreno – scienzeedintorni, 4 April 2008
Finalmente alla ribalta il più grande fra i vulcani sommersi nel Tirreno, il Monte Marsili – scienzeedintorni, 29 March 2010

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Chile tsunami: images of the aftermath 3 March 2010

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Dichato, Chile, February 2010 (Juan Eduardo Lopez, El Mercurio)

The Chilean newspaper El Mercurio has published a series of dramatic high-definition aerial photographs of the devastation caused along Chile’s coast by the tsunami associated with the 27 February 2010 earthquake.

Fotos aéreas del terremoto en ChileEl Mercurio, 2 March 2010

[Thanks go to Guillermo for the link.]

The Volcanism Blog

Chile: big quake = more volcanic activity? 2 March 2010

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The M8.8 earthquake that hit Chile at the weekend has raised the question of whether such large quakes have any effect on activity in nearby volcanoes. In Chile itself, geologists from Chile’s Observatorio Volcanológico Andes del Sur (OVDAS) have publicly ruled out any such connection; New Scientist, by contrast, has a headline excitedly claiming ‘Volcanic explosions expected in Chile quake’s wake’.

The New Scientist article refers to a research paper by Sebastian Watt, David Pyle and Tamsin Mather of the University of Oxford which appeared in Earth and Planetary Science Letters in 2008 (‘The influence of great earthquakes on volcanic eruption rate along the Chilean subduction zone’, Earth and Planetary Science Letters, vol. 277, nos. 3-4, 30 January 2009, Pages 399-407 [doi:10.1016/j.epsl.2008.11.005]). This paper looked into a potential connection between earthquakes and increased local volcanic activity in Chile over the past two centuries, and concluded that there was some evidence of such a connection:

We show a significant increase in eruption rate following earthquakes of MW > 8, notably in 1906 and 1960, with similar occurrences further back in the record. Eruption rates are enhanced above background levels for ~ 12 months following the 1906 and 1960 earthquakes, with the onset of 3–4 eruptions estimated to have been seismically influenced in each instance.

Given the claim that the ‘enhanced’ eruption rates may manifest over around 12 months after the earthquake, OVDAS’s denial that the 27 February quake will produce an increase in volcanic activity is premature. However, the 2008 paper raises many questions about the nature of the mechanisms at work, the time lag involved, and the real significance of the phenomenon (an estimated 3-4 additional eruptions is not very many). As Erik Klemetti has just observed,

Complex systems have many inputs – maybe the volcano that erupts next week would have erupted with a magnitude 4 earthquake, maybe it would have erupted without an earthquake at all. To connect the two merely because they are temporally juxtaposed is not scientifically sound. There is evidence that there could be an effect on nearby volcanism after large earthquakes in some settings, however, it is far from proven.

A further point is that, whatever New Scientist‘s headline writer may think, not all volcanic activity is explosive, or even dangerous in any way. Increased volcanic activity does not necessarily equate to increased hazard – as David Pyle points out in the New Scientist article: ‘At volcanoes that are already active we might see an increase in steam explosions, but we don’t expect it to present a significantly increased danger’. So even if there is a volcano-earthquake connection, and the question very much remains open, it is not necessarily something people living in active subduction zones should consider an additional significant threat.

N.B. ‘Llaima, one of the largest and most active volcanoes in Chile, is back on the watch list’, says the caption to a dramatic picture of Llaima accompanying the New Scientist story. In fact Llaima has been ‘on the watch list’ (if that means ‘at higher alert’) since mid-February, but of course it increases the drama to imply that the raised alert level is the result of the earthquake, and if that misleads your readers, so what?

News
Descartan que volcanes Llaima y Villarrica estén con actividad irregular luego de terremotoLa Tercera, 28 February 2010
Descartan que el terremoto un aumento de la actividad volcánica – Europa Press, 1 March 2010
Completa normalidad se observa en volcanes de la zonaEl Austral, 1 March 2010
Volcanic explosions expected in Chile quake’s wakeNew Scientist, 1 March 2010

The Volcanism Blog

Magnitude 8.8 earthquake in Chile 27 February 2010

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A large earthquake has taken place off the coast of Chile. The quake occurred at 03:34 am local time (06:34 GMT) today. The USGS initially reported a magnitude of 8.3, but that has just been upgraded to 8.8. The earthquake was located off Maule, 325 km SW of the capital Santiago and 115 km NNE of the city of Concepción, with a reported depth of 35 km. The NOAA Pacific Tsunami Warning Center (home page) reports that a tsunami warning has been issued for Chile and Peru, and a tsunami watch has been issued for Ecuador, Colombia, Antarctica, Panama and Costa Rica. The BBC reports that the Japan Meteorological Agency ‘has warned of a potential tsunami across the Pacific’ (NOAA tsunami travel time map).

Little news is available from Chile at the time of posting (it is less than two hours since the earthquake). La Tercera is reporting at least two deaths, power cuts, damage to communications networks and extensive property damage. UPDATE: Reuters, quoting Chilean President Michele Bachelet, reports that ‘at least six people’ have been killed.

FURTHER UPDATE: The confirmed death toll has risen to 47, and a state of emergency has been declared in the most seriously affected regions of central Chile. Chilean television station 24 Horas is now (11:31 GMT) reporting 64 dead. Live streaming of Chilean television (24 Horas) here.

[The Volcanism Blog will be back on Monday.]

The Volcanism Blog

Landslide provokes volcano fears in northern Peru 21 February 2010

Posted by admin in natural hazards, not-a-volcano, Peru.
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Peruvian news outlets are full of reports of a landslide in San Luis de Lucma district, Cutervo Province, which is in the northern Cajamarca Region of Peru. This is not a part of the country normally associated with volcanic activity (in Peru the active volcanoes are found in the far south), but local inhabitants apparently believed that a volcano was erupting and asked to be evacuated: local sources say up to 2000 people wanted to be moved out. Some news reports speak of an ‘explosion’ and dust clouds including ‘sulphur’:

The strange event occurred at approximately one in the afternoon, affecting about 20 hectares of farmland, where at the moment of the explosion there were people working their lands with their animals, who have been buried. The mayor of San Luis de Lucma, Santos Delgado Fernández, said that there were at least 100-150 victims after the blast, the majority residents of villages around the scene of the incident. ‘They have lost crops and animals’, he said. Local inhabitants said that after the explosion took place the area was transformed into a dust cloud, putting the health of hundreds of locals at risk through the emanation of smoke and sulphur that can cause asphyxiation.

Landslides are not uncommon in Peru and can be deadly, particularly in the rainy season (a fatal landslide occurred last month in the south). This area of northern Peru has no history of volcanic activity so the fears of a volcanic eruption are almost certainly the products of panic and a misunderstanding of the nature of the event. The local head of Civil Defence, Miguel Alva, is quoted as saying that this was a landslide, and that it is not uncommon for landslides to generate ‘a large cloud of smoke’. Similarly, the director of seismology at the Instituto Geofísico del Perú, Hernán Tavera, has affirmed that this was a landslide caused by recent rains and not a volcanic event: ‘There is no volcano in the country north of Ayacucho’. The blast and smell of sulphur, Tavera says, would have been caused by the disruption of thermal springs in the area of the landslide.

The landslide has disrupted local water supplies and affected a nearby hydroelectric plant. Around 300 people were affected by the event, and latest reports say that eight people are missing and five houses were buried.

The Volcanism Blog

Insuring against volcanic disaster 13 February 2010

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How does the insurance industry view volcanoes? As a big risk, naturally. Most volcanoes do little damage, but when volcanic damage to life and property does occur it can be extensive and long-lasting (deposits from the 1980 eruption of Mount St Helen’s, for example, are still causing problems thirty years later). How does one insure property built on or near active volcanoes (e.g. Hawaii)? Is it possible to insure against the harmful effects of volcanic emissions (e.g. Turrialba)? Can insurance offer peace of mind to the farmer fearing a scoria cone may appear in his back yard (e.g. Paricutin, or even Ballarat)? And what will be the effects upon the insurance business of a major urban centre being significantly damaged or destroyed by a volcanic eruption (e.g. Naples, Seattle and many others)?

Lloyds of London have been pondering these issues, as you might expect; and so has the insurance-industry-funded Aon Benfield UCL Hazard Research Centre. Among the conclusions reached is that while most natural disasters are usually defined by insurers as lasting no more than 72 hours, volcanic eruptions can be considered for insurance purposes as lasting up to 672 hours. Find out more by reading ‘Bubbling under – disasters waiting to happen’ at the Lloyds of London website.

The Volcanism Blog

Soufrière Hills ashfall causes problems 21 December 2009

Posted by admin in activity reports, Caribbean, Soufrière Hills.
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Soufrière Hills volcano on the Caribbean island of Montserrat has been vigorously active recently, with the growing lava dome producing collapses, explosions, pyroclastic flows and considerable ash emissions.

Since 19 December south-easterly winds have caused ashfall in the inhabited north-west of the island. On 20 December the Montserrat Volcano Observatory reported ‘heavy ashfall in many inhabited areas of northwestern Montserrat on Saturday 19 December’ and forecast that ashfall would continue through Sunday and until at least the early hours of Monday.

According to reports on the Caribbean Hurricane Network, ash from Soufrière Hills reached islands north-west of Montserrat including St Maarten, Saba and Nevis. Caribbean airline LIAT has issued a warning that air travel between St Kitts, Nevis, St Maarten, Anguilla and Guadeloupe may be affected by Soufrière Hills ashfall.

[Thanks go to Barb Beier.]

For all our Soufrière Hills coverage: Soufrière Hills « The Volcanism Blog.

Information
Global Volcanism Program: Soufrière Hills – information about Soufrière Hills volcano (1600-05=)
Montserrat Volcano Observatory – comprehensive news and information from the MVO

The Volcanism Blog

El Misti at the NASA Earth Observatory 2 November 2009

Posted by admin in El Misti, NASA Earth Observatory, natural hazards, Peru.
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El Misti volcano and Arequipa, Peru, 16 October 2009 (NASA astronaut photograph)

The Peruvian volcano El Misti is very close to the country’s second city of Arequipa: just 17 km separates the city with its ~1 million inhabitants from the volcano’s crater. The image above, a mosaic of two ISS astronaut photographs that is today’s Image of the Day at the NASA Earth Observatory, shows the potentially dangerous relationship clearly. Larger versions of the image, and a full commentary, are available over at the Earth Observatory. There is, however, no scale bar on the Earth Observatory images, so I have added one to the small version above.

El Misti Volcano and Arequipa, Peru – NASA Earth Observatory (2 November 2009)

[Astronaut photographs ISS021-E-8370 and ISS021-E-8371 were acquired on 16 October 2009 by the Expedition 21 crew. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth.]

Information
Global Volcanism Program: El Misti – summary information for El Misti (1504-01=)
Instituto Geológico Minero y Metalúrgico – Geological, Mineral and Metallurgical Institute of Peru (Ingemmet)

The Volcanism Blog

Taiwan volcano: active, dormant, or what? 2 November 2009

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The Tatun (or Datun) volcano group (TVG) is in the north of Taiwan, 15 km to the north of the capital, Taipei. New research in the area by a Taiwanese/Russian scientific team involving the dating of eruption products at is now provoking alarm, it says here:

Datun Mountain, a dormant volcano located on the north of Taipei City, is an active volcano with a possible magnitude that can devastate the entire wider Taipei area with approximately six million residents if eruption occurs, a new study by the Academia Sinica says. The recent report used volcanic ash and mudflow in the analysis and claimed that Datun Mountain was an active volcano. A previous study had showed that the last eruption occurred 200,000 years ago and classified it as a dormant volcano.

The new study appears to suggest that the most recent eruption was a mere 5000 years ago: hence headlines claiming Taipei risks volcanic devastation, alarming comparisons between a putative eruption and the earthquakes of 1999, and even that old favourite, warnings of a new Pompeii. However, the most recent eruptive activity before the latest study had been dated at 20,000 years ago, not 200,000 years ago, so it was already understood that the volcano had been active in relatively recent times. The Global Volcanism Program notes: ‘The latest dated eruptions in the group took place over a roughly 3000-year period beginning about 20,000 years ago’.

Overall, it is not news that there is risk of potential activity at Tatun. An article in the Journal of Volcanology and Geothermal Research in 2007 described the Tatun Volcano Group as ‘a potentially active Quaternary volcano’ and noted that ‘Because of lack of any activity in historical times it has been classified as an extinct volcano, even though more recent studies suggest that TVG might have been active during the last 20 ka’ (in any case, when assessing whether a volcano is extinct or dormant, ‘activity in historical times’ is no guide). The article went on to observe that seismic studies ‘indicate that a magma chamber may still exist beneath TVG and that a future eruption or period of unrest should not be considered unlikely’.

There’s nothing wrong in waking up the people of northern Taiwan to the risks posed by their local volcano, but (as ever) sensationalized press reports are perhaps not the best way to do it.

UPDATE. Taiwan News Online quotes Chaing Chung-jung of the Taiwan Central Geological Survey: ‘Chiang said that the possibility of the mountain erupting again is “extremely low”. “Besides, volcanic eruptions can be predicted”, he said, urging that there is no need for people to panic over the matter’. This story still claims, erroneously, that the ‘last eruption of Datun Mountain occurred 200,000 years ago’, however.

Information
Global Volcanism Program: Tatun Group – information on the Tatun Volcano Group (0801032A)
Yangmingshan National Park: Datun Mountain – information from the Yangmingshan National Park website

News
Datun Mountain is active, can devastate Taipei: studyThe China Post, 2 November 2009
Volcano near Taiwan’s capital is still active, scientists warnMy Sinchew, 2 November 2009

The Volcanism Blog

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