GeoLog

Geochemistry, Mineralogy, Petrology & Volcanology

Extraordinary iridescent clouds inspire Munch’s ‘The Scream’

Screaming clouds

Edvard Munch’s series of paintings and sketches ‘The Scream’ are some of the most famous works by a Norwegian artist, instantly recognisable and reproduced the world over. But what was the inspiration behind this striking piece of art?

The lurid colours and tremulous lines have long been thought to represent Munch’s unstable state of mind; a moment of terror caught in shocking technicolour. At the same time, scientists have recently identified the connection between the great works of artists such as William Turner and the red and orange sunsets which can be a result of the global impact of volcanic aerosols. However, research presented this week at the European Geosciences Union General Assembly in Vienna by atmospheric scientists in Oslo Norway, suggests that the painting might show us evidence of something much stranger, and rarer – nacreous clouds.

Nacreous or mother-of-pearl clouds, are an extremely rare form of cloud created 20-30km above sea level – in the polar stratosphere when the air is extremely cold (between -80 and -85 degrees centigrade) and exceptionally humid,. So far observed mostly in the Scandinavian countries, these clouds are formed of microscopic and uniform particles of ice, orientated into thin clouds. When the sun is below the horizon (before sunrise or after sunset), these clouds are illuminated in a surprisingly vibrant way blazing across the sky in swathes of red, green, blue and silver. They have a distinctive wavy structure as the clouds are formed in the lee-waves behind mountains.

In 2014, these clouds were seen again over the skies of Oslo and given their extreme colouration and unexpected appearance, a photographer, Svein Fikke, immediately thought of Munch’s work. This perceived similarity between the mother of pearl clouds and the striking clouds and sense of tension in the painting is only reinforced when reading Munch’s writings about his experiences on the day that inspired the painting.

“I went along the road with two friends – the sun set

I felt like a breath of sadness –

– The sky suddenly became bloodish red

I stopped, leant against the fence, tired to death – watched over the

Flaming clouds as blood and sword

The city – the blue-black fjord and the city

– My friends went away – I stood there shivering from dread – and

I felt this big, infinite scream through nature”

                            Edvard Munch’s Diary Notes 1890-1892 (Tøjner and Gundersen, 2013)

Scientists have, in the past, used artworks to infer environmental conditions; from paintings of the ‘frost fairs’ held on the River Thames that show the gradual environmental change in Europe, to the discovery that several artists depict the influence of volcanic aerosols on global atmosphere in their paintings.

In a study conducted in 2007 (and 2014), scientists found that the visible impact that volcanic aerosols have on the atmosphere has in fact been recorded in the works of many of the great masters – particularly William Turner (Zerefos et al, 2007)). Several of Turner’s paintings depict sunsets with a distinct red/orange hue, distinct from his usual work of other years. This was correlated with significant volcanic eruptions in the same time period and the researchers found that these reddish paintings were all created in the years of, or immediately following, a major eruption (shown in the graph below).

Graph to show the relationship between colour and volcanic aerosols (a)The mean annual value of R/G measured on 327 paintings. (b)The percentage increase from minimum R/G value shown in (a). (c)The corresponding Dust Veil Index (DVI). The numbered picks correspond to different eruptions as follows: 1. 1642 (Awu, Indonesia-1641), 2. 1661 (Katla, Iceland-1660), 3. 1680 (Tongkoko and Krakatau, Indonesia-1680), 4. 1784 (Laki, Iceland-1783), 5. 1816 (Tambora, Indonesia-1815), 6. 1831 (Babuyan, Philippines-1831), 7. 1835 (Coseguina, Nicaragua-1835). 8. 1883 (Krakatau, Indonesia-1883). From Zerefos et al (2007).

For many years ‘The Scream’ was thought to also show the influence of a volcanic eruption, most likely the catastrophic eruption of Krakatoa in 1883 (described here by Volcanologist David Pyle), but whereas volcanic skies tend to tint the whole sky a red/orange, the skies in the scream have a distinct pattern, only seen in these extremely rare nacreous clouds.

How rare are they? Well, researcher Dr Helene Muri, a researcher based at the University of Oslo, who presented the research at the press conference, said that in her lifetime living mostly in Norway as an atmospheric researcher she has only seen them once. And what about Munch’s feeling of dread and ‘breath of sadness’?

Well, having a glowing swathe of iridescent petrol coloured clouds flare into bright relief after sunset, only for them to disappear 30 minutes later would be pretty shocking for any of us, even in our modern days of fluorescent streetlamps and light polluted skies.

By Hazel Gibson, EGU Press Assistant at the EGU 2017 General Assembly

Imaggeo on Mondays: In the belly of the beast

In the belly of the beast . Credit: Alexandra Kushnir (distributed via imaggeo.egu.eu)

Conducting research inside a volcanic crater is a pretty amazing scientific opportunity, but calling that crater home for a week might just be a volcanologist’s dream come true, as Alexandra postdoctoral researcher at the Institut de Physique du Globe de Strasbourg, describes in this week’s Imaggeo on Mondays.

This picture was taken from inside the crater of Mount St Helens, a stratovolcano in Washington State (USA). This particular volcano was made famous by its devastating explosive eruption in 1980, which was triggered by a landslide that removed most of the volcano’s northern flank.

Between 2004 and 2008 Mount St Helens experienced another type of eruption – this time effusive (where lava flowed out of the volcano without any accompanying explosions). Effusive eruptions produce lava flows that can be runny (low-viscosity) like the flows at Kilauea (Hawaii) or much thicker (high viscosity) like at Mount St Helens. Typically, high viscosity lavas can’t travel very far, so they begin to clump up in and around the volcano’s crater forming dome-like structures.  Sometimes, however, the erupting lava can be so rigid that it juts out of the volcano as a column of rock, known as a spine.

The 2004 to 2008 eruption at Mount St Helens saw the extrusion of a series of seven of these spines. At the peak of the eruption, up to 11 meters of rock were extruded per day. As these columns were pushed up and out of the volcanic conduit – the vertical pipe up which magma moves from depth to the surface – they began to roll over, evoking images of whales surfacing for air.

‘Whaleback’ spines are striking examples of exhumed fault surfaces – as these cylinders of rock are pushed out of the volcano their sides grind against the inside of the volcanic conduit in much the same way two sides of a fault zone move and grind past each other. These ground surfaces can provide scientists with a wealth of information about how lava is extruded during eruption. However, spines are generally unstable and tend to collapse after eruption making it difficult to characterize their outer surfaces in detail and, most importantly, safely.

Luckily, Mount St Helens provided an opportunity for a group of researchers to go into a volcanic crater and characterise these fault surfaces. While not all of the spines survived, portions of at least three spines were left intact and could be safely accessed for detailed structural analysis. These spines were encased in fault gouge – an unconsolidated layer of rock that forms when two sides of a fault zone move against one another – that was imprinted with striations running parallel to the direction of extrusion, known as slickensides. These features can give researchers information about how strain is accommodated in the volcanic conduit. The geologist in the photo (Betsy Friedlander, MSc) is measuring the dimensions and orientations of slickensides on the outer carapace of one of the spines; the southern portion of the crater wall can be seen in the background.

Volcanic craters are inherently changeable places and conducting a multi-day field campaign inside one requires a significant amount of planning and the implementation of rigorous safety protocols. But above all else, this type of research campaign requires an acquiescent mountain.

Because a large part of Mount St Helens had been excavated during the 1980 eruption, finding a safe field base inside the crater was possible. Since the 2004-2008 deposits were relatively unstable, the science team set up camp on the more stable 1980-1986 dome away from areas susceptible to rock falls and made the daily trek up the eastern lobe of the Crater Glacier to the 2004-2008 deposits.

Besides being convenient, this route also provides a spectacular tableau of the volcano’s inner structure with its oxidized reds and sulfurous yellows. The punctual peal of rock fall is a reminder of the inherent instability of a volcanic edifice, and the peculiar mix of cold glacier, razor sharp volcanic rock, and hot magmatic steam is otherworldly. That is, until an errant bee shows up to check out your dinner.

By Alexandra Kushnir, postdoctoral researcher at the Institut de Physique du Globe de Strasbourg, France.

This photo was taken in 2010 while A. Kushnir was a Masters student at the University of British Columbia and acting as a field assistant on the Mount St Helens project.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

 

March GeoRoundUp: the best of the Earth sciences from around the web

March GeoRoundUp: the best of the Earth sciences from around the web

Drawing inspiration from popular stories on our social media channels, as well as  unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major story

While the March headlines might not have been dominated by a particular story, the state of the Earth’s climate has definitely been the overarching theme of the month.

Ahead of World Meteorological Day (celebrate on the 23rd March) the World Meteorological Organization released its annual report on the State of Global Climate. Compiled from a broad range of sources, the report reiterates the findings of the US government agencies NASA and NOAA, who earlier this year declared that 2016 was the warmest year on record.

Not only were temperatures a remarkable 1.1 °C above the pre-industrial period and 0.06 °C above the previous record set in 2015, global sea ice extent dropped more than 4 million square kilometres below average in November. Boosted by a strong El Niño event global sea levels reached record highs too.

The report comes in the wake of US President Trump’s ‘blueprint’ budget for 2018, where he sets out his spending priorities for the year ahead. Nature put together a piece that highlights what US science would stand to lose if the budget is approved. NASA would experience a 0.8% cut from current levels, largely focused on Earth science missions, and future NOAA satellite programmes are also under threat. Worst hit by the cuts would be the Environment Protection Agency (EPA), with a proposed 31% cut in funding, which would “gut EPA programs tackling climate change and pollution”, according to The Guardian.

But the signals are clear: after the record warming in 2016, temperatures have continued to rise in 2017, affecting ecosystems around the world. An example are the corals of the Great Barrier Reef,  which have suffered from widespread bleaching – a situation where they expel their symbiotic algae, meaning they turn white and can die – for the third consecutive year. A new study on mass bleaching of corals was discouraging news: the only long-term solution to the problem is halting global warming. Improving water quality or enforcing fishing controls provides little relief.

But it’s not all bad news when it comes to the global climate and the Earth’s environment. Despite being a record-breaking year in terms of temperatures, 2016 was also the year that saw a dramatic drop in the amount of new coal fueled power plants being built. With cities worldwide battling poor air quality and pollution, this is certainly encouraging news.

What you might have missed

Earlier this month a BBC News crew experienced the fickle nature of volcanoes first hand. The team were visiting Mt. Etna (Sicily) to film a report on volcano monitoring, and  arrived on the Italian island to discover Europe’s most active volcano had just started to erupt again.

Etna’s slow-moving lava is not usually considered dangerous. “But about 20 minutes after arriving, a burst of white steam emerged from the lava – it didn’t make much of a noise or look especially threatening – but the guides started asking people to move. Then, moments later, there was an explosion,” writes Rebecca Morelle, one of the reporters on the team. As they ran down the mountain to safety, the team and tourists, were “pelted with deadly, hot debris.” Read the full account of their ordeal and watch a spectacular video here.

It has also been a big month for palaeontology. Up until now the shape of a dinosaur’s hip determined were along the dinosaur family tree it was placed. Lizard-hipped dinosaurs fell into one group (Saurischia), while those with a more bird-like hip configuration are known as Ornithischia. Now, a team of researchers have proposed a radically new classification system. They found that 21 other anatomical features divide the dinosaurs differently. The new tree puts theropods together with Ornithischian, indicating they probably share a common ancestor. The new theory might face an uphill struggle to debunk the long-lasting consensus on the history of dinosaurs, but many in the field agree that given the thoroughness of the study it is certainly an idea worth considering.

Scientists from the Museum and Cambridge University have proposed radical changes to the dinosaur family tree. Credit: Natural History Museum.

And while we are on the subject of dinosaurs, this brilliant interactive map of every fossil found on Earth (created by @PaleoDB) is a great resource!

Way out in space, the bounty of insights from the Rosetta mission continues. From September 2014, the mission scientists have kept a watchful eye on a 70 m-long, 1 m-wide fracture on the prominent cliff-edge subsequently named Aswan, in the Seth region of the comet, on its large lobe. A few days later, new images of the area revealed that the crack had disappeared and been replaced by a new cliff face, at the bottom of which were many new meter-sized boulders. The discovery allowed the scientists to make the link between the newly created cliff face and outbursts of dust and gas.

You might think the use of infographics to visualise data is a relatively new thing, but you’d be mistaken. This collection of 1800s educational diagrams, of scientific discoveries, from the moon’s surface to the longest rivers, is simply stunning and incredibly effective.

Emslie and Reynolds compare mountains and volcanoes, including mountains in the Alps and Andes. Featured in Geological Diagrams. Courtesy David Rumsey Historical Map Collection

Links we liked

  • Something for the weekend? Why not try your hand at baking a scientifically accurate (sort of!) cake planet?
  • New research suggests that by the middle of the century, more than half of humanity will live in water-stressed areas. Badly managed resources play a crucial role in water shortages globally
  • For a lighthearted, yet very informative, take on mass extinctions this story in The Atlantic is not to be missed
  • A German coal-mine, which has provided power for the country’s industry sector for the past half century, will get a new lease on life when it’s turned into a into a pumped-hydro-storage station, acting like a giant battery that stores solar and wind energy

The EGU story

This time of year, EGU’s biggest story is our annual General Assembly, starting only a few weeks from now. This month, we published the meeting programme, which includes some 1000 sessions and over 17,500 abstracts! On the blog, we published guides on how-to make the best of your oral, poster or PICO presentation at the General Assembly, revealed the finalists of the Communicate Your Science Video Competition, and provided tips on making the most of your time in Vienna without breaking the bank. We look forward to seeing you all in the Austrian capital in the last week of April!

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

Imaggeo on Mondays: Lava highway in Kanaga Island

Imaggeo on Mondays: Lava highway in Kanaga Island

On a rare sunny day, Mattia Pistone (a researcher at the Smithsonian Institution in Washington DC) was able to capture this spectacular shot of Kanaga, a stratovolcano in the remote Western Aleutians, which is usually veiled by thick cloud.

The Western Aleutians form a chain of 14 large and 55 small volcanic islands, belonging to one of the most extended volcanic archipelagos on Earth (1900 km), stretching from Alaska across the northern Pacific towards the shores of Russia.

As part of a team of researchers, Mattia spent three grueling weeks in the isolated region. Being one of the most extended volcanic arc systems on Earth, the Aleutians can shed light on one of the most fundamental questions in the Earth sciences: how do continents form?

The Earth’s landmasses are made of continental crust, which is thought to be largely andesitic in composition. That could mean it is dominated by a silicon-rich rock, of magmatic origin, which is fine grained and usually light to dark grey in colour. However, basaltic magmas derived from the Earth’s upper mantle and erupted at active volcanoes contribute to chemistry of the continental crust. The fact that continental crust bears the chemical hallmarks of both suggests that the formation of new continents must somehow be linked to motion of magma and its chemistry.

Establishing the link between magma generation, transport, emplacement, and eruption can therefore significantly improve our understanding of crust-forming processes associated with plate tectonics, and, particularly, help determining the architecture and composition of the continental crust. The Alaska-Aleutian archipelago is a natural laboratory which offers a variable range of volcanic rocks. The islands present a perfect opportunity for scientists to try and understand the origin of continents.

By collecting samples of volcanic ash erupted at Kanaga and other volcanoes of the Aleutian arc, Mattia and his colleagues are currently investigating the origin of this volcanic ash. Understanding its chemistry allow the team to get a clearer idea of the conditions that were present while the magma was forming and ascending, for example, how much water and iron were present.

The team were based on the Maritime Maid research vessel, and hoped from island to island collecting samples and taking measurements of volcanic activity as part of a large research consortium called GeoPRISMS, funded by the National Science Foundation. The field work was supported by a Bell 407 helicopter and its crew.

Today’s featured image shows an andesitic lava flow erupted in 1906. The volcanic deposits were explored during the field geological mission by Mattia and the team. Kanaga last erupted in 1994. Ash from that eruption was found in the nearby island of Adak. Even at present, there is a highly active system of fumaroles at the summit of the volcano.

If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

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