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Evacuations planned in Vanuatu as Gaua activity steps up 19 April 2010

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Gaua volcano, Vanuatu, 12 April 2010 (NASA Terra MODIS image)
Gaua volcano, Vanuatu: a MODIS image from the NASA Terra satellite, 12 April 2010 (source: NASA Earth Observatory, 15 April 2010).

Gaua volcano in northern Vanuatu has been showing signs of increased activity for some months: in November 2009 there were evacuations of villagers from Gaua island because of ashfall and gas emissions. During January 2010 ash emissions became denser and darker, and gas emissions increased. Strombolian activity and explosions were reported at the end of January. From late March into April ash plumes were reported daily, reaching altitudes of up to 3 km, and reports of explosions, ash fall and the ejection of volcanic bombs continued.

Gaua volcano, Vanuatu, 14 February 2010 (NASA EO-1 ALI image)
The Mount Garet cone of Gaua volcano erupting on 14 February 2010, captured by the Advanced Land Imager aboard NASA’s Earth Observing-1 satellite. The crescent-shaped body of water is Lake Letas, which partially fills the Gaua caldera (source: NASA Earth Observatory, 18 February 2010).

Today news sources are reporting that extensive evacuations are being planned, involving the transfer of about 2700 people from Gaua or Santa Maria Island to a relocation centre on nearby Vanualava Island. According to Peter Korisa of the Vanuatu Government emergencies office the volcano’s activity is not stable, but increasing: ‘Last year it was just some explosions and some ash falling but at the moment the activity is becoming more interesting’. The evacuation is not yet being carried out, but the necessary plans have been made. At the moment, Korisa says, ‘the situation doesn’t warrant any evacuation’, but the authorities are ready to act should such a step prove necessary.

The alert level for Gaua remains at its habitual level 2, according to the Vanuatu Geohazards Observatory.

UPDATE 20 April 2010. A reader has correctly pointed out that the previous headline for this post, ‘Evacuations in Vanuatu as Gaua activity steps up’, gave the impression that the evacuations are already under way. This is not the case, the evacuations are only at the planning stage, and I have changed the headline to reflect the situation accurately. Thanks, TJ, for the correction.

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

News
Vanuatu prepares evacuation from rumbling volcano – AFP, 19 April 2010
Vanuatu prepares evacuation amid threats of Gaua volcano – Radio New Zealand International, 19 April 2010

Information
Global Volcanism Program: Gaua – summary information for Gaua (0507-02=)
Vanuatu volcanoes and volcanics – information from the USGS Cascades Volcano Observatory

The Volcanism Blog

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Infrasound monitoring for Marianas volcanoes 26 February 2010

Posted by admin in Pacific, United States, volcano monitoring.
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Left: Pagan volcano erupting, 18 May 1981. Right: Anatahan erupting, 16 June 2003. (Both images courtesy USGS.)
Left: Pagan erupting, 18 May 1981. Right: Anatahan erupting, 16 June 2003. (Both images courtesy USGS.)

A new programme in the Northern Marianas Islands will use infrasound technology alongside conventional seismometers and other equipment to monitor the archipelago’s active volcanoes. The partners behind the project to enhance volcano monitoring in the Marianas are the Northern Marianas Commonwealth Government, the U. S. Geological Survey and Southern Methodist University (SMU). SMU scientists have been responsible for the application of infrasound to the detection of nuclear explosions in order to monitor test ban compliance.

The project chief, Professor James Quick, explains that infrasound used alongside conventional monitoring techniques will add a new dimension to the interpretation of volcanic signals: ‘My hope is that we’ll see some distinctive signals in the infrasound that will allow us to discriminate the different kinds of eruptive styles — from effusive events that produce lava flows, or small explosive events we call vulcanian eruptions, to the large “Plinian” events of particular concern to aviation. They are certain to have some characteristic sonic signature’.

The planned development of the Marianas as a forward deployment base for the United States military has given particular urgency to the improvement of volcano monitoring in the archipelago.

Volcanic eruptions produce much more sound than human ears can detect – in particular, they are prolific and efficient radiators of low-frequency sound, in the infrasonic bandwith below the threshold of human hearing. These low-frequency sounds are detectable at great distances and are little affected by passage through the atmosphere. Volcano monitoring using infrasound offers several benefits:

  • It is unaffected by inclement weather, darkness and poor visibility.
  • It offers the potential for a detailed understanding of internal volcanic dynamics in both eruptive and non-eruptive states.
  • It avoids the complication of variations in local conditions and monitoring arrangements, making comparisons between different volcanoes easier.
  • It can be used to clarify and interpret obscure and enigmatic seismicity.

More information about volcanic infrasound monitoring can be found at the INFRAVOLC site run by New Mexico Tech.

News
USGS-SMU volcano monitoring will target hazard threat to Marianas, U.S. military and commercial jets – SMU News Release, 24 February 2010*

Information
Global Volcanism Program: Anatahan – information about Anatahan (0804-20=)
Global Volcanism Program: Pagan – information about Pagan (0804-17=)
Northern Mariana Islands volcanic activity – from the Marianas government
North Pacific Volcanic Islands – information from the USGS

* Lots of detail in the news release, but it contains two Wikipedia links, ugh. A reputable university should know better.

The Volcanism Blog

Deepest undersea eruption caught on video 18 December 2009

Posted by admin in current research, Pacific.
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An explosion at the West Mata Volcano throws ash and rock, with molten lava glowing below (NSF/NOAA)
An explosion at the West Mata Volcano throws ash and rock, with molten lava glowing below (image courtesy NSF/NOAA).

In May this year scientists studying the West Mata submarine volcano in the south-west Pacific as part of the NOAA Vents Program captured the deepest undersea eruption yet filmed on video (as your favourite volcano bloggers reported at the time). The findings and images have just been presented at the AGU Fall Meeting in San Francisco: the NOAA has two videos and a wealth of still imagery. West Mata is at the northern end of the Tonga Arc, and rises to 1174 metres below sea level. The water around the vents is highly acidic: microbial life is present, but shrimps are the only form of animal life to thrive around the vents.

News
Scientists discover and image explosive deep-ocean volcano – NOAA, 17 December 2009
Marine scientists discover deepest undersea erupting volcano – EurekAlert, 17 December 2009
Deepest volcano caught on Pacific Ocean video – BBC News, 18 December 2009
Underwater volcano eruptsThe Times, 18 December 2009
Robot records deepest erupting undersea volcano – Associated Press, 18 December 2009
Oceanographers image the discovery of the deepest explosive eruption on the sea floor – PhysOrg.com, 17 December 2009

Information
Global Volcanism Program: West Mata – summary information for West Mata (0403-13-)
Neovolcanic activity in the NE Lau Basin – blog of the West Mata expedition

The Volcanism Blog

Vanuatu’s volcanoes at the NASA Earth Observatory 9 December 2009

Posted by admin in Ambrym, Gaua, NASA Earth Observatory, Pacific, Vanuatu.
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Vanuatu, showing Gaua and Ambrym volcanoes, 3 December 2009 (NASA MODIS image)

This image, from the NASA Earth Observatory (click on the image to view the original full-size version) shows the northern part of the Republic of Vanuatu in the south-west Pacific. It was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite on 3 December 2009 and shows two currently active Vanuatu volcanoes: Ambrym (bottom right) and Gaua (top left). Detail views of both are shown below.

The current eruptive phase at Ambrym, which has a history of frequent eruptions over the last 2000 years or so, began in May 2008; an earlier Earth Observatory image showed an instance of the vog that Ambrym’s sulphur dioxide emissions can produce. Gaua, meanwhile, which last erupted in 1982, has been restless since the autumn of this year: evacuations were recently ordered when gas and ash emissions from its active cone (Mt Garat) were making life impossible for the inhabitants of nearby villages. Another very active Vanuatu volcano, Yasur, is out of shot to the south.

Ambrym volcano, Vanuatu, 3 December 2009 (NASA MODIS image detail)
Above: Ambrym volcano, Vanuatu, emitting a thin plume to the west on 3 December 2009.

Gaua volcano, Vanuatu, 3 December 2009 (NASA MODIS image detail)
Above: Gaua or Santa Maria island and Gaua volcano, Vanuatu, on 3 December 2009. The lake partially filling the 6 x 9 km caldera has developed a crescent shape because of the construction of the currently active cone of Mt Garat. The brown marking on the western side of the island shows where recent gas emissions from Mt Garat have caused damage to vegetation.

Information
Global Volcanism Program: Ambrym – summary information for Ambrym (0507-04=)
Global Volcanism Program: Gaua – summary information for Gaua (0507-02=)
Vanuatu Geohazards Observatory – official Vanuatu geohazards website
Vanuatu volcanoes and volcanics – information from the USGS Cascades Volcano Observatory

The Volcanism Blog

Vanuatu: Gaua volcano update 28 November 2009

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The Vanuatu Geohazards Observatory has published a fresh update on the situation at Gaua volcano, which has recently shown an increased level of activity, forcing evacuations. Gaua Bulletin No. 3, dated 24 November (but only just published on the Observatory’s website) reports ‘a big explosion of the Gaua volcano in November 18th 2009 at 2pm’ followed by ‘very thick and high emissions of ash columns that were covering the areas exposed to trade winds in the West’. Photographs show the comparative size of the ash plume on 31 October and 18 November. The bulletin also notes that there was an increase in seismicity at the volcano from 25 October onwards.

The alert level for Gaua remains unchanged at 2 (‘moderate eruptions’).

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

Information
Global Volcanism Program: Gaua – summary information for Gaua (0507-02=)
Vanuatu Geohazards Observatory – official Vanuatu geohazards website
Vanuatu volcanoes and volcanics – information from the USGS Cascades Volcano Observatory

The Volcanism Blog

Vanuatu: Gaua evacuations continue 27 November 2009

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The evacuation of residents of Gaua island in northern Vanuatu is continuing, reports Radio New Zealand International (RNZI). The active cone of Gaua volcano, Mt Garet, which has been showing low-level eruptive activity for around two months, has increased its activity over the last few days: gas emissions and ashfall have seriously affected life in the island’s eastern portion, and people from that area are being moved by boat to the unaffected western region of the island. RNZI reports that gas masks are being sent to Gaua, and that tourists are being warned to keep away from the volcano.

No update yet on the current activity at the Vanuatu Geohazards Observatory website, but in fairness it must be pointed out that the observatory’s hard-pressed staff are working with very limited resources (they don’t even have the seismographs they need to monitor Gaua adequately).

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

News
Gas masks sent to Vanuatu island where locals are forced to evacuate – Radio New Zealand International, 26 November 2009
Tourists warned off Vanuatu’s Gaua volcano – Radio New Zealand International, 27 November 2009

Information
Global Volcanism Program: Gaua – summary information for Gaua (0507-02=)
Vanuatu volcanoes and volcanics – information from the USGS Cascades Volcano Observatory

The Volcanism Blog

Evacuations in Vanuatu as Gaua activity increases 26 November 2009

Posted by admin in activity reports, eruptions, Gaua, Pacific, Vanuatu.
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Gaua volcano in northern Vanuatu is reported to have erupted early today. At the moment there is no official news from Vanuatu itself, but regional news sources (see below) are reporting that gas emissions and ash fall have increased during the past two days and that 300 residents of the eastern half of Gaua island are being evacuated by the Vanuatu Government and the Red Cross to the west of the island.

Efline Garaebiti, head of the Vanuatu Government disaster monitoring team, is reported by Australian news sources as saying that it is ‘unlikely’ that Gaua volcano ‘will erupt completely’, which suggests that this is an increase in the ongoing emissions of gas and ash rather than a full-scale eruption. Strong winds in recent days may also have increased the effects of the emissions on the local population.

The Vanuatu Geohazards Observatory website has no report as yet on the current situation, and the alert level for Gaua remains at level 2, ‘minor eruption’.

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

News
Vanuatu volcano forces hundreds to evacuate – Australia Network News, 26 November 2009
Pacific volcano erupts, leading to evacuation of hundredsNew Straits Times, 26 November 2009
Volcano erupts in Vanuatu: Red CrossSydney Morning Herald, 26 November 2009
300 evacuated from villages in Vanuatu due to gas and ash from volcano – Radio New Zealand International, 26 November 2009

Information
Global Volcanism Program: Gaua – summary information for Gaua (0507-02=)
Vanuatu volcanoes and volcanics – information from the USGS Cascades Volcano Observatory

The Volcanism Blog

Activity continuing at Vanuatu’s Gaua volcano 20 October 2009

Posted by admin in activity reports, eruptions, Gaua, Pacific, Vanuatu.
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Both ABC’s Australia Network News and Radio New Zealand International are reporting today that the alert level for Gaua volcano in northern Vanuatu has been raised from 1 to 2, as reported here four days ago.

The ABC story reports that SO2 emissions at the volcano have risen from nil to 3000 tonnes/day, as recorded on 3 October by volcanologist Philipson Bani: ‘for this small volcano this is huge’. Local residents are reporting a strong smell of sulphur and ash falling on their crops.

News
Ash and fumes pour from Vanuatu volcano – ABC Australia Network News, 20 October 2009
Alert level raised for Vanuatu volcano – Radio New Zealand International, 20 October 2009

Information
Global Volcanism Program: Gaua – summary information for Gaua (0507-02=)
Vanuatu Geohazards Observatory – geohazards home page for Vanuatu
Vanuatu volcanoes and volcanics – information from the USGS Cascades Volcano Observatory

The Volcanism Blog

Warning of ‘insufficient monitoring’ as Gaua activity continues 8 October 2009

Posted by admin in activity reports, Gaua, Pacific, Vanuatu, volcano monitoring.
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Scientists monitoring the currently restless Gaua volcano in Vanuatu are relying on just one polyseismograph, leading a local seismologist to warn that insufficient monitoring is putting lives at risk:

We need back up for seismic monitoring because for the time being we have just one polyseismograph but we really need back up of two or three extra seismographs in order to locate the events.

The volcano remains on level one of the five-level alert system (where five is the highest level). Meanwhile, large earthquakes north-west of Vanuatu have shaken the area up, but with no tsunami or serious damage or loss of life. These were tectonic quakes which have no relation to the volcanic activity in Vanuatu, except in so far as both are products of subduction zone processes.

News
Seismologist says insufficient monitoring of Vanuatu volcano endangering lives – Radio New Zealand International, 8 October 2009

Information
Global Volcanism Program: Gaua – summary information for Gaua (0507-02=)
Vanuatu volcanoes and volcanics – information from the USGS Cascades Volcano Observatory

The Volcanism Blog

Increased activity reported at Gaua 7 October 2009

Posted by admin in activity reports, Gaua, Pacific, Vanuatu.
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The spate of restlessness at Gaua volcano in Vanuatu is evidently continuing. Radio New Zealand International reports that more activity has been observed by the volcanological team sent to Gaua to assess the situation. One of the team reports that very late on 5 October ‘an increase of a high volcanic high frequency’ was observed, which is presumably a reference to high frequency volcanic tremor.

The current alert level at Gaua is one, on a scale of one (lowest) to five (highest). The volcano is being closely monitored, and if there are further increases in activity the alert level will be increased to two, say the volcanologists.

News
Close eye kept on Vanuatu volcano that’s spitting ash – Radio New Zealand International, 6 October 2009

Information
Global Volcanism Program: Gaua – summary information for Gaua (0507-02=)
Vanuatu volcanoes and volcanics – information from the USGS Cascades Volcano Observatory

The Volcanism Blog