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Arenal activity continues, tourists dice with death 17 April 2009

Posted by admin in activity reports, Arenal, Costa Rica, natural hazards, volcano tourism.
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Seismicity at Arenal volcano in Costa Rica remains elevated, with continuing rock-fracture earthquakes caused by magma movement within the volcanic system (online seismograph displays for Arenal, along with other Costa Rican volcanoes, are available from the Observatorio Vulcanológico y Sismológico de Costa Rica: Sismogramas en línea). Monitoring was stepped up at Arenal at the beginning of this month, and warnings were issued to tourists visiting the Arenal National Park over the Easter holiday.

It seems to have made no difference, however. The Costa Rican newspaper La Nación reports today that Costa Rican and foreign tourists ‘are entering dangerous areas in the vicinity of the crater of Arenal volcano, despite the presence of notices warning of the increased seismic activity that could cause avalanches’. Visitors have apparently been getting in via neighbouring private property to evade police and park ranger controls, or are being brought into the park by people masquerading as official guides in order to earn money, regardless of the risks. ‘Because [the tourists] are uninformed or unconcerned, they are wandering through the area of greatest danger. They are putting their lives on the line’, warns the head of the tourist police, José David Rojas.

Arenal and its surrounding park form a popular tourist attraction, but the volcano is not tame and has to be treated with respect. In August 2000 three people died on Arenal when they were engulfed by a pyroclastic flow: they were in an area identified as dangerous at the time.

News
Turistas invaden zonas de riesgo en volcán ArenalLa Nación, 17 April 2009

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

The Volcanism Blog

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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

Arenal: recent activity 10 June 2008

Posted by admin in activity reports, Arenal, Costa Rica, volcanoes.
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Arenal volcano in Costa Rica is a youthful and vigorous stratovolcano, almost continually active since its current phase of activity began with a violent and deadly eruption in 1968. To quote the Global Volcanism Program’s Arenal summary, ‘Continuous explosive activity accompanied by slow lava effusion and the occasional emission of pyroclastic flows has occurred since then from vents at the summit and on the upper western flank’.

The most recent instance of this type of activity was reported by the Observatorio Vulcanológico y Sismológico de Costa Rica (the inevitable acronym is OVISCORI) on 6 June 2008. A pyroclastic flow was generated on the south-western flank of Arenal when an accumulation of blocky, andesitic lava at the summit, the remnant of a March 2007 lava flow, collapsed. The flow descended some 800m, with pulverized material rising from it to produce a tall plume of gases and dust that provoked alarm in tourists and park officials The park was quickly evacuated and closed, no-one was hurt, and there was no further activity.

Bulletins on this activity (PDF) in both Spanish and English can be accessed from OVISCORI’s ‘Informes de Prensa’ page.

Arenal provides a fascinating case study in the ways human societies interact with and live alongside active volcanoes: its spectacular but largely safe activity attracts thousands of visitors, and it is at the heart of a national park that is one of Costa Rica’s main tourist attractions, while the lake at the foot of the volcano, Lago Arenal, has become the site of a large hydroelectric scheme that provides around 40% of the country’s electricity. Arenal.net, a travel-oriented site, offers a great deal of information about the volcano including maps, photographs and links.

UPDATE: There’s a report on what’s happened at Arenal, with some nice clear discussion of the science behind this kind of activity, over at Erik’s Eruptions blog.

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

The Volcanism Blog