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Undersea explosive eruptions named ‘neptunian’ 5 July 2009

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Two researchers from the School of Earth Sciences and Centre of Excellence in Ore Deposits (CODES) at the University of Tasmania have come up with the name ‘neptunian’ to describe undersea explosive volcanic eruptions, says a report at ScienceDaily.

These eruptions are sustained and driven by gas exsolved from magma … Neptunian eruptions differ dramatically from magmatic-gas-driven explosive eruptions on land, reflecting the important influence of confining pressure and the higher heat capacity, density, and viscosity of water compared to air.

The original article (abstract here) by Sharon R. Allen and Jocelyn McPhie of CODES can be found in Geology: Sharon R. Allen and Jocelyn McPhie, ‘Products of neptunian eruptions’, Geology, July 2009, pp. 639-642 [DOI 10.1130/G30007A.1].

N.B. Not to be confused with Neptunism.

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Watching volcanoes: Natural Environment Research Council podcast 19 May 2009

Posted by admin in Caribbean, current research, geoscience, Soufrière Hills, volcano monitoring, volcanology.
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The Natural Environment Research Council ‘is the UK’s main agency for funding and managing research, training and knowledge exchange in the environmental sciences’ (says the NERC ‘what we do’ page). The NERC is responsible for the British Antarctic Survey and the British Geological Survey, among many many other things, and has a strong commitment to natural hazards research, including (of course) volcanoes. To give a notable current example of the NERC’s involvement in this field, it provided emergency funding for the recent important studies of ashfall at Chaitén carried out by a University of Oxford research team.

All this is by way of background, and to point out that if you’re interested in volcanological and natural hazards research, the NERC is an agency to watch. Today there’s a new podcast available on the NERC’s Planet Earth Online environmental news service: ‘Watching volcanoes’. In the podcast (duration 6 min 42 sec) Richard Hollingham talks to Dr Sue Loughlin and Dr Kathryn Goodenough of the British Geological Survey about how studying currently active volcanoes (Montserrat) and the remains of ancient volcanoes (Edinburgh) informs our knowledge of volcanic processes and improves our ability to forecast future volcanic behaviour. It’s a model of clear exposition and an excellent example of scientific outreach.

The Planet Earth podcast – ‘Watching volcanoes’ (18 May 2009)

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Volcanoes take a holiday, glaciers rule the world 14 May 2009

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Around 2.4 billion years ago plate tectonics shut down, volcanism took a break for 250 million years, and glaciers spread across the world’s surface, it says here.

Volcano ‘vacation’ produced first glaciers – Discovery News, 14 May 2009

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Volcano research miscellany 7 May 2009

Posted by admin in Africa, current research, geoscience, Hawaii, Kilauea, Ol Doinyo Lengai, Pacific, submarine volcanism, Tanzania, United States.
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Various interesting bits and pieces of volcano-related research to report. Apologies for the lack of detail, but I’m pressed for time right now.

Ash evidence suggests impact of past eruptions underrated – a research team from the University of Oxford has studied the distribution of ash from the Chaitén eruption and concluded that the impact of past volcanic eruptions is likely to have been significantly underestimated, because so much ashfall is light (a few millimetres thickness) and is quickly lost from the areas affected. More on this at Science Daily, under the snappy headline Chaitén Volcano In Southern Chile: Historic Volcanic Eruptions Significantly Underestimated, Ash Fallout Analysis Shows.

Origins of Ol Doinyo Lengai’s weird lavas probed – the unique carbonatite lavas of Ol Doinyo Lengai volcano in Tanzania are produced by a very low degree of partial melting of the upper mantle minerals, concludes research to be published shortly in Nature by U.S. and French scientists. Science magazine’s ScienceNOW (caps lock stuck down?) news service also has an article on this, bafflingly entitled Volcanic Fish Out of Water.

Thriving ecosystem supported by NW-Rota 1 – scientists who have just returned from filming and studying the deep undersea volcano NW-Rota 1 report that the active volcano nourishes a rich and thriving biological community including shrimps, crabs, limpets and barnacles, some of which are new species. National Geographic News has some pictures.

Gentle, easy-going Kilauea has a dangerous side – between 1000 and 1600 years ago Kilauea, known today for its gentle tourist-friendly lava flows, chucked rocks 16 or 17 kilometres during powerful explosive eruptions.

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Dominica volcano poses Caribbean tsunami risk – researchers 21 April 2009

Posted by admin in Caribbean, current research, geoscience, natural hazards.
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Morne aux Diables is an 861-metre high stratovolcano at the northern tip of the island of Dominica in the eastern Caribbean. It is a little-known volcano: the Global Volcanism Program does not have an ‘eruptive history’ page for Morne aux Diables, noting that ‘No eruptions are known from Morne aux Diables in historical time’ but that ‘the volcano has a youthful appearance and activity at flank domes likely continued into the late-Pleistocene and Holocene’.

As discussed recently in these pages, a volcano does not have to erupt to be dangerous, and recent research by a team of geologists led by Dr Richard Teeuw of the University of Portsmouth concludes that Morne aux Diables may be very dangerous indeed. Geomorphological surveys by Dr Teeuw’s team and evidence from Google Earth3-D imaging have revealed that one flank of the volcano is in danger of collapse. If a flank collapse occurs at Morne aux Diables a tsunami could be triggered that would threaten the heavily-populated coast of Guadeloupe, 50 kilometres north of Dominica.

Dr Teeuw’s team plans to return to Dominica this summer, and again in 2010, to study the geomorphology of the volcano, and to survey the seafloor for evidence of previous collapses.

News
Research shows Caribbean at risk of tsunami – University of Portsmouth news release, 21 April 2009
Devil’s volcano is tsunami risk to Caribbean island – Bloomberg, 21 April 2009
Caribbean at risk of tsunami, disaster experts warn – ScienceDaily, 21 April 2009
Volcano ‘poses tsunami threat’ in Caribbean – AFP, 21 April 2009
Tsunami threat from Dominica’s Devil’s Peak – RedOrbit, 21 April 2009

Information
Global Volcanism Program: Morne aux Diables – summary information for Morne aux Diables (1600-08=)
Tsunami generation mechanisms from volcanic sources – interesting paper by George Pararas-Carayannis (try to ignore the shocking page design)

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Scientists return to active undersea volcano 20 March 2009

Posted by admin in current research, geoscience, Pacific, submarine volcanism.
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In 2004 an international team of scientists using a remotely-operated submersible witnessed an undersea volcanic eruption for the first time at Northwest Rota-1, a seamount rising to 517 metres below the sea surface in the Mariana Islands. Further scientific studies were carried out at the site in 2005 and 2006. Last year hydrophones recorded sounds of eruptive activity at the site.

In April this year the scientific team will be returning to Northwest Rota-1 for further studies, says a press release from Oregon State University:

During the two-week project, the scientists will deploy long-term monitoring instruments including hydrophones, chemical sensors, current meters and plume sensing devices that will allow them to study for the first time the patterns of activity over an entire year. They also will make additional visual observations of the eruptive activity, hydrothermal vents and biological communities, and will collect samples of lava, gas and fluids from the volcano.

It will be fascinating to see what they come up with. The NOAA website for the April 2009 cruise can be found here: Vents Program: Marianas.

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Volcanoes’ jet-like roar 17 March 2009

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Infrasonic recordings of volcanic eruptions, when accelerated to bring the frequencies within the range of human hearing, reveal similarity to the noises made by jet engines, say the authors of a paper in Geophysical Research Letters. Such recordings could offer a new way of understanding what is going on in volcanic eruption columns, it says here.

  • R. S. Matoza, D. Fee, M. A. Garces, J. M. Seiner, P. A. Ramon, & M. A. H. Hedlin (2009), ‘Infrasonic jet noise from volcanic eruptions’, Geophysical Research Letters, in press [doi:10.1029/2008GL036486]. Link to PDF, subscribers only.

News
Volcanic roar may reveal jet physics at workNew Scientist, 16 March 2009

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Is Nyiragongo atop a growing mantle plume? 13 March 2009

Posted by admin in Africa, Congo (Dem. Rep.), current research, geoscience, Nyiragongo, volcanology.
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The highly fluid, fast-moving lava produced by Nyiragongo volcano in the Democratic Republic of the Congo presents a dangerous volcanic hazard. In January 2002 the volcano erupted 14–34 × 106 m3 of lava from vents on its southern flanks, engulfing thousands of buildings in the nearby city of Goma and surrounding villages, killing about 50 people and leaving 120,000 people homeless. Twenty-five years earlier, in January 1977, a large death toll – possibly in the hundreds, and thought by some to be in the thousands – resulted from a similar eruption which produced lava flows with peak speeds estimated at 100km/h.

So what makes Nyiragongo’s lava unique? New research by Asish Basu of the University of Rochester (and others), published in Chemical Geology, suggests that a mantle plume is emerging beneath the volcano, feeding it with magma from a very deep source:

‘This is the most fluid lava anyone has seen in the world … It’s unlike anything coming out of any other volcano. We believe we’re seeing the beginning of a plume that is pushing up the entire area and contributing to volcanism and earthquakes.’

Basu analyzed the lava, which resides in the world’s largest lava lake—more than 600 feet wide inside the summit of Nyiragongo—and found that the isotopic compositions of neodymium and strontium are identical to ancient asteroids. This suggests, says Basu, that the lava is coming from a place deep inside the Earth where the source of molten rock is in its pristine condition.

For more details, see the press release from the University of Rochester. The paper itself is available to subscribers or to purchase via ScienceDirect:

  • Ramananda Chakrabarti, Asish R. Basu, Alba P. Santo, Dario Tedesco & Orlando Vaselli, ‘Isotopic and geochemical evidence for a heterogeneous mantle plume origin of the Virunga volcanics, Western rift, East African Rift system’, Chemical Geology, vol. 259, issues 3-4 (25 February 2009, pp. 273-289 [doi:10.1016/j.chemgeo.2008.11.010]

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New sulphur dioxide monitoring methods – improving volcano and climate monitoring 13 March 2009

Posted by admin in climate, current research, geoscience, natural hazards, volcano monitoring, volcanology.
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A press release from the Swedish Research Council reports the work of Matthias Johansson, doctoral student in the Department of Radio and Space Science at Chalmers University in Göteborg, who has developed a system of measuring sulphur dioxide output from volcanoes by aggregating measurements taken from two or more instruments. Much of the work on the project ‘has involved making the equipment sufficiently automatic, robust, and energy-efficient for use in the inhospitable environment surrounding volcanoes, in poor countries with weak infrastructure’. The equipment is currently in use at seventeen locations.

The research also has implications for improved global climate monitoring by providing continuous measurements of the levels of sulphur dioxide emitted into the atmosphere by the world’s most active volcanoes:

‘Sulfur dioxide is converted in the atmosphere to sulfate particles, and these particles need to be factored into climate models if those models are to be accurate’, says Associate Professor Bo Galle, who directed [Johansson's] dissertation. Volcanoes are an extremely important source of sulfur dioxide. Aetna alone, for instance, releases roughly ten times more sulfur dioxide than all of Sweden does.’

The Chalmers research is part of Project Novac, a European Union funded project to establish networks for the measurements of volcanic gases and aerosols, and apply the data obtained to risk analysis and volcanological research, locally and on a regional and global scale.

UPDATE: I missed Ole Nielsen’s post of yesterday on this, at Olelog – Volcanic Eruption Forecasting.

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New Zealand undersea volcanism at the Eruptions blog 12 March 2009

Posted by admin in current research, geoscience, New Zealand, submarine volcanism.
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Dr Klemetti has an interesting post at his Eruptions blog today on undersea volcanism in the Kermadec Arc, north of New Zealand. A study by the University of Southampton and the University of Washington found evidence of a high level of volcanic activity in this area, with the delightfully-named Rumble III volcano having apparently filled in its crater and lost 100m in height since 2007. Eruptions has all the information and relevant links: Volcanoes old and new in New Zealand.

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