Could there really be such a thing as volcano season?
16 hours ago by Robin Wylie, The Conversation
The Earth seems to have been smoking a lot recently. Volcanoes are currently erupting in Iceland, Hawaii, Indonesia and Mexico. Others, in the Philippines and Papua New Guinea, erupted recently but seem to have calmed down. Many of these have threatened homes and forced evacuations. But among their less-endangered spectators, these eruptions may have raised a question: Is there such a thing as a season for volcanic eruptions?
Surprisingly, this may be a possibility. While volcanoes may not have "seasons" as we know them, scientists have started to discern intriguing patterns in their activity.
Eruptions caused by a shortened day
The four seasons are caused by the Earth's axis of rotation tilting towards and away from the sun. But our planet undergoes another, less well-known change, which affects it in a more subtle way. Perhaps even volcanically.
Due to factors like the gravitational pull of the sun and moon, the speed at which the Earth rotates constantly changes. Accordingly the length of a day actually varies from year to year. The difference is only in the order of milliseconds. But new research suggests that this seemingly small perturbation could bring about significant changes on our planet – or more accurately, within it.
In February 2014, a study in the journal Terra Nova showed that, since the early 19th century, changes in the Earth's rotation rate tended to be followed by increases in global volcanic activity. It found that, between 1830 and 2013, the longest period for which a reliable record was available, relatively large changes in rotation rate were immediately followed by an increase in the number of large volcanic eruptions. And, more than merely being correlated, the authors believe that the rotation changes might actually have triggered these large eruptions.
Altering the spin of a planet, even by a small amount, requires a huge amount of energy. It has been estimated that changes in the Earth's rotation rate dissipate around 120,000 petajoules of energy each year – enough to power the United States for the same length of time. This energy is transferred into the Earth's atmosphere and subsurface. And it is this second consequence that the Terra Nova authors believe could affect volcanoes.
The vast quantities of energy delivered to the subsurface by rotation changes are likely to perturb its stress field. And, since the magma which feeds volcanic eruptions resides in the Earth's crust, stress variations there may make it easier for the liquid rock to rise to the surface, and thereby increase the rate of volcanic eruptions.
The Terra Nova study is far from conclusive. Nevertheless, the idea that minute changes to the Earth's spin could affect volcanic motions deep within the planet is an intriguing one.
But there's another natural phenomenon which has a much stronger claim to affect volcanic activity – one which might be just as surprising: climate change.
Eruptions caused by climate change
In recent decades, it has become apparent that the consequences of planetary ice loss might not end with rising sea levels. Evidence has been building that in the past, periods of severe loss of glaciers were followed by a significant spike in volcanic activity.
Around 19,000 years ago, glaciation was at a peak. Much of Europe and North America was under ice. Then the climate warmed, and the glaciers began to recede. The effect on the planet was generally quite favourable for humankind. But, since the mid-1970s, a number of studies have suggested that, as the ice vanished, volcanic eruptions became much more frequent. A 2009 study, for example, concluded that between 12,000 and 7,000 years ago, the global level of volcanic activity rose by up to six times. Around the same period the rate of volcanic activity in Iceland soared to at least 30 times today's level.
There is supporting evidence from continental Europe, North America and Antarctica that volcanic activity also increased after earlier deglaciation cycles. Bizarrely, then, volcanic activity seems – at least sometimes – to rise and fall with ice levels. But why? Again, this strange effect might be down to stress.
Eruptions cause by the melting of ice
Ice sheets are heavy. Each year, Antarctica's loses around 40 billion tonnes. They are so heavy, in fact, that as they grow, they cause the Earth's crust to bend – like a plank of wood when placed under weight. The corollary of this is that, when an ice sheet melts, and its mass is removed, the crust springs back. This upward flexing can lead to a drop in stress in the underlying rocks, which, the theory goes, makes it easier for magma to reach the surface and feed volcanic eruptions.
The link between climate change and volcanism is still poorly understood. Many volcanoes do not seem to have been affected by it. Nor is it a particularly pressing concern today, even though we face an ice-free future. It can take thousands of years after the glaciers melt for volcanic activity to rise.
Yet while it may not be an immediate hazard, this strange effect is a reminder that our planet can respond to change in unforeseen ways. Contrary to their brutish reputation, volcanoes are helping scientists understand just how sensitive our planet can be.http://phys.org/news/2014-09-volcano-season.html
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UK city set to be heated by VOLCANO - lifting thousands out of fuel poverty
- Sep 25, 2014
- By Agency staff
Stoke-on-Trent council and business leaders says the 350m-year-old rocks can provide a source of abundant and renewable energy
A 350 million-year-old volcano could soon be heating one of the largest cities in the Midlands.
Less than two miles beneath Stoke-on-Trent, Staffs, is a layer of rocks heating water to up to 105 degrees Celsius.
Experts think it is so hot because it is linked to volcanic activity back in the Devonian period.
Now council and business leaders believe this source of abundant and renewable energy can solve rising fuel costs faced by residents and employers.
Stoke-on-Trent City Council's £52 million plans for a geothermal district heating network (DHN) involves bringing hot water to the surface through a borehole and transferring the heat to clean water.
This will then be pumped to buildings in the city's districts of Hanley, Stoke and Festival Park through 11 kilometres of pipes, providing customers with a cheap form of heating.
While relatively common in continental Europe, only one geothermal DHN has ever been built in the UK.
£52m
Cost of project
11,700
CO2 saved per year (tonnes)
1,300
Jobs safeguarded
But the city council, which hopes to unlock £19.75 million of government funding, believes the technology is the way forward.
The authority claims the project has the potential to lift 1,000 households out of fuel poverty, save 11,700 tonnes of CO2 a year and safeguard at least 1,300 jobs.
Professor Peter Styles, from Keele University, said the science behind geothermal district heat networks is proven.
He added: "This volcano from millions of years ago has left behind unstable isotopes which could now be generating heat a few kilometres down.
"It's a bit like having a hot water bottle in the ground.
"In this country, there has been more interest in exploiting the higher temperatures seen in granite moorland, but the trouble with that is that it isn't where people live.
"If you look at industrial cities, such as Stoke-on-Trent, Sheffield or Newcastle-upon-Tyne, they all sit on coalfields, so that would appear a more feasible way of exploiting geothermal."
Eruption in Papua New Guinea this month
District heating works like a central heating system, but on a much larger scale.
Each property will have a pair of pipes, with isolating valves and a heat meter, connecting it to the network, eliminating the need for a conventional boiler.
While the network of pipes will remain under the council's control, private sector partners will be expected to build and operate the £17 million geothermal well and sell the heat to customers.
If all goes to plan, work will start in 2016 and the scheme will be completed by March 2019.
http://www.mirror.co.uk/news/technology-science/science/uk-city-set-heated-volcano-4324210~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Iceland volcano 'pollutes Paris'
25/09 19:21 CET
- 25/09 07:41
Iceland witnessed 40 earthquakes on Wednesday (September 24), which saw lava flow from an active volcano arrive within 200 metres of a highland road. There is currently no indication that the eruption will calm down.
Pollution emanating from the molten magma is said to have travelled as far as the French capital Paris, where at-risk groups are being advised to limit outdoor activity to a minimum.
http://www.euronews.com/2014/09/25/iceland-volcano-pollutes-paris/
Media Advisory: 10th Anniversary of the Mount St. Helens Reawakening and Eruption of 2004-2008
Released: 9/24/2014 3:00:00 PM
Contact Information: U.S. Department of the Interior, U.S. Geological Survey Office of Communications and Publishing 12201 Sunrise Valley Dr, MS 119 Reston, VA 20192 | Liz Westby Phone: 360-993-8979 Leslie Gordon Phone: 650-329-4006 |
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VANCOUVER, Wash.— In the early morning hours of September 23, 2004, a swarm of small-magnitude earthquakes about half a mile below Earth's surface marked the reawakening of Mount St. Helens after 18 years of eruptive quiescence. Steam and ash explosions on October 1 were followed by three years of lava extrusion that formed a new dome inside the crater. The lava dome pushed Crater Glacier aside, causing it to flow rapidly toward the front of the 1980 breach; flow continues today. Scientists at the U.S. Geological Survey's Cascades Volcano Observatory and its partners used many techniques during the 2004-2008 eruption to monitor the volcano, including interpretation of seismicity, ground deformation, thermal imaging, and lava sampling. By monitoring Mount St. Helens, scientists are better able to understand the volcano's behavior, to assess hazards and potential impacts, and to provide timely warnings of future events.
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