Badlands national park, South Dakota, USA by Iain Willis (distributed via imaggeo.egu.eu).
The selection committee received over 200 photos for this year’s EGU Photo Contest, covering fields across the geosciences. Participants have been voting for their favourites throughout the week and there are three clear winners. Congratulations to – 2015’s fantastic photographers!
Heiturpottur. Credit: Morgan Jones (distributed via imaggeo.egu.eu)
You don’t form in the wet sand by Nicasio T. Jiménez-Morilo (distributed via imaggeo.egu.eu).
On the occasion of the International Year of Soils, the judges also awarded an honourable mention to the best image in the Soil System Sciences category submitted to the EGU Photo Contest. The chosen image was ‘You don’t form in the wet sand’ by Nicasio T. Jiménez-Morilo. .
In addition, this year, to celebrate the theme of the EGU 2015 General Assembly, A voyage through scales, the photo that best captured the theme of the conference was selected by the judges. The winner is the stunning ‘Badlands National Park’, by Iain Willis! Congratulations! Scroll to the top of this post to view Iain’s image.
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/.
The conference is coming to a close and there’s still an abundance of great sessions to attend! Here’s our guide to getting the most out of the conference on its final day. Boost this information with features from EGU Today, the daily newsletter of the General Assembly – pick up a paper copy at the ACV entrance or download it here.
Be sure to attend today’s Jean Dominique Cassini Medal Lecture by Jonathan I. Lunine, who will be discussing habitable environments and life in the Saturn system (ML4, 12:15 in Y1).
It’s your last chance to make the most of the networking opportunities at the General Assembly, so get on down to the poster halls and strike up a conversation. If you’re in the queue for coffee, find out what the person ahead is investigating – you never know when you might start building the next exciting collaboration! Here are some of today’s scientific highlights:
The final Union Symposium (US4) this week is dedicated to planetary interiors and how advances in space observations have furthered our ability to understand what is inside planetary bodies. Talks begin at 08:30 in Y5. Our final Great Debate of the week, which is co-organised with the AGU (American Geophysical Union), will be on open access publishing. The discussion kicks off at 15:30 in Room R1.
Today we also announce the results of the EGU Photo Contest and the Communicate Your Science Video Competition. Head over to the EGU Booth at 12:15 to find out who the winners are.
Following the success of this year’s theme, EGU 2016 will also have a theme: Active Planet. Join us on this adventure in Vienna next year (17–22 April 2016)!
What have you thought of the Assembly this week? Let us know at www.egu2015.eu/feedback and help make EGU 2016 even better.
We hope you’ve had a wonderful week and look forward to seeing you in 2016!
Nibbling round the edges. Credit: Maria Hernandez-Soriano (distributed via imaggeo.egu.eu)
Vienna skyline. (Credit: Mimikama, distributed via Pixabay)
The General Assembly is coming to an end, with only one full day left to go. Many of the participants will make their way home over the weekend, but if you’ve chosen to stay on for a little longer, then this list of cultural activities and things to do in Vienna might just be the ticket!
Rear of the opera house, showing the stage wings. (Credit: Markus Leupold-Löwenthal, distributed by Wikimedia Commons).
Opera for All
This event takes great performances out of the opera house and into the open square. This Saturday, you can experience L’Italiana in Algeri for free. The performance starts at 19:00, make sure you’re at the Staatsoper early to get a seat!
After your busy week at EGU, treat yourselves to something sweet at chocolate emporium Xocolat, a boutique and workshop where you can watch chocolatiers at work and even try your hand at making chocolate yourself! Situated in the 9th district, beneath the stone arches of the Ferstel passage, Xocolat offers the creations of Catalan chocolatier Enric Rovira, Californian Scharffen Berger and Austrian brand Zotter. http://www.xocolat.at/de/
Vienna Residence Orchestra
Spend an evening in Vienna’s most beautiful palaces this week to unwind after your week at EGU. Wiener Residenzorchester, or the Vienna Residence Orchestra, are a chamber orchestra with a long
tradition of playing Viennese classics in Vienna’s most beautiful palaces. The enchanting sounds of the orchestra, accompanied by opera singers and ballet dances will take you on a journey through Imperial Vienna. http://www.wro.at/vienna-classics/
Eclectic flea market
From buckets of tulips to pickles, wines and plump, and purple-flushed figs, you can find it all at the Naschmarkt. Saturday can be busy, so a early start it best!
Location: 4, Linke und Rechte Wienzeile. U1, U2, U4 Karlsplatz.
Get a view of Vienna
It may be cliche, but no trip to Vienna is complete without a ride on the 19th-century Riesenrad or giant ferris wheel. It’s the only remaining work of British engineer Walter Basset who also built wheels for Blackpool, London and Paris.
The Eastern Ukinrek Maar, Alaska. Credit: R. Russell, Alaska Department of Fish and Game, USGS.
Following his session at the EGU General Assembly, Greg Valentine (Buffalo University) spoke to Sara Mynott about how he creates model volcanoes, specifically maar-diatremes, and blows them up to better understand what goes on in an eruption…
So what is a maar-diatreme?
A diatreme is a vent-like structure, mostly made up of broken up bedrock and magma. Initially, you have a dyke that channels magma straight up to the surface, but somewhere along the line the magma interacts with groundwater. This causes explosions below ground, which start to build up zones of debris. Once you get a debris-filled zone, the magma comes up in fingers that probably facilitate further interaction with water.
Tell me a little about your experiments…
We have an experimental site near Buffalo, New York. It’s out in the countryside, so we can be messy and loud.
We dig a trench (20m long, 4m wide and 2m deep) and make craters between 1 and 2 metres in diameter. It’s like landscaping. We have a guy who normally works in gardens, he comes and digs the trench, and we go shopping at quarries and buy different types of sand and gravel to fill it, bringing in truckloads and truckloads of sediment. But first we add some explosives.
What we’re trying to do is relate what we see in a surface eruption to what goes in the subsurface. In the experiments we can completely control that – from what makes up the sediment layers to the amount of energy and where the explosion occurs.
How much explosive energy do you put into your experiments and how does that compare to what you would see naturally?
We’re working with about a million Joules – it’s about half a stick of dynamite, something like that. The natural explosions are maybe 3 to 6 orders of magnitude larger.
Valentine and his team were standing about 75m away from the explosion, but that didn’t stop a couple of stray rocks landing behind them! Here, the plume is about 15 m high and the clumps of sand that are being thrown out are several centimetres across. The scaled depth? Just right. Credit: Graettinger et al. (2014).
How does the depth and energy of the explosion affect what happens in an eruption?
To tackle this we use this thing called scaled depth, which relates the depth of the explosion to the energy involved. This way of characterising underground explosions has been used for over a hundred years, by people who do mining, geotechnical engineering and weapons testing.
We know that if we have a very small scaled depth, most of the energy goes into the atmosphere. You get a big bang – it’s very dramatic, it’s very fun, you can see the camera shaking when the shockwave hits the camera, but it doesn’t excavate that much of a crater. If you get it too deep, so the scaled depth is really large, nothing comes out. This is because more of the energy is being absorbed by the ground. So there’s this intermediate scaled depth where you get the most crater excavation.
How often do these explosions occur at a particular location or at different depths? Is there any regular pattern at a particular volcano?
We don’t understand enough yet to be able to say that, except that there are probably many – perhaps hundreds – of explosions at a natural maar-diatreme. We suspect that probably more of the explosions happen near the surface because there’s less confining pressure – something that acts against the explosion.
The depth? Too deep. The ground goes up when the shockwave hits it from below, but then it sinks. Look closely – the tennis balls on the surface are used as ballistic markers, but rather than being thrown out in the explosion, they sink as the ground subsides to form a small crater. Credit: Graettinger et al. (2014).
What proportion of the world’s volcanoes are maar-diatremes?
If you just counted each volcano on Earth, not including under the ocean, maar-diatremes would be the second most abundant. They tend to be what we call monogenetic – they have one eruptive episode that may be a few weeks to a few years long and they’re dead.
Usually, they occur in what we call volcanic fields, which, instead of having one central cone, have many small volcanoes over an area. There are many such fields in Europe, including Chaîne des Puys in France and Campi Flegrei in Italy. A volcanic field may have an eruptive period every 1,000 years or so, some more frequent and some less frequent.
What risk do maar-diatremes pose to the human population?
Many of these volcanic fields are inhabited. If an eruption occurred close to Naples, there would be tens to thousands of people affected. Auckland, New Zealand, is almost entirely built on a young volcanic field. It’s dormant right now, but sometime something will happen. Mexico City is another one.
If an explosion were to occur close to the surface in one of these places, what impact would it have?
It could make a crater that is 100-200 metres in diameter and throw blocks – big rocks – 100s of metres from the volcano, probably generate a lot of ash and pyroclastic flows.
What do you love most about your job?
The flexibility to pursue different lines of research wherever they take me.
Finally, what advice would you give a young scientist wanting to get into experimental volcanology the way that you have?
They should make sure they have a good physics and math background, try to get an internship with somebody and just dive in!
By Sara Mynott, Press Assistant at the 2015 General Assembly and PhD student at the University of Exeter.