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Geodynamics

Imaggeo on Mondays: Strombolian eruption

Imaggeo on Mondays: Strombolian eruption

Jonas Kuhn, a researcher at Heidelberg University , took the photograph during a field campaign at Stromboli volcano in Italy. The objective of this campaign was to gather data from different gaseous compounds of the volcanic plume. Via emission fluxes of volcanic gases (e.g. SO2, CO2, halogen compounds…) or the ratio of emitted gases, one can retrieve information about the interior of the volcano and magma dynamics. Volcanic gas measurements can therefore contribute to better understanding volcanoes and in predict volcanic activity.

There are several ways in which scientists can gather information about volcanic processes from plume gas measurements. Let’s start by taking a look at sulphur dioxide, as it is emitted by volcanoes in large amounts. A relatively novel measurement instrument, the SO2 Camera, is able to record 2D SO2 distributions with a high time resolution. This means that SO2 emission fluxes can be determined and linked to other volcanological data sets as e.g. seismic data or simply to the occurrence of explosions. The high resolution SO2 emission fluxe data can give insight into the footprints of volcanic processes like the bursting of gas bubbles in the magma. So depending on e.g. the viscosity of the magma one would expect different frequencies in the emission flux of different volcanoes.

“In our group, a lot of work was done on further developing such camera systems. In volcanology this technique has only been applied for the past decade,” explains Jonas.

Another innovative device for fast optical in situ measurement of SO2 andCO2, as well as chemical in situ measurements of halogen compounds in the plume was also tested during the field trip. By using the ratios of other gases to SO2 and the known SO2 flux (from the SO2 camera measurement), fluxes of the other gases can be estimated. Different gases have different solubilities in magma, so they are released from the magma at different pressures.  Ratios of gas abundances in the volcanic plume can therefore contain information on, for instance, changes in the magma level (it’s not uncommon for magma to be ‘invisible’ in the interior of the volcano). The magma level can also be a crucial indicator of volcanic activity.

“What made this field campaign special was that relatively new and young volcanic measurement techniques were tested and used,” outlines Jonas, who goes on to point out ““many of them are still in the development stages. The volcanic gas measurement field is very exciting at this time. Interesting insights have been gained in the last decades and there is still a lot of ideas and new technologies coming up.”

By Jonas Khun,  Researcher at Heidelberg University and Laura Roberts Artal, EGU Communications Officer

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/.

Imaggeo on Mondays: The place where water runs through rocks

Imaggeo on Mondays: The place where water runs through rocks

Antelope Canyon, located in Arizona, USA, was formed by erosion of the Navajo Sandstone, primarily due to flash flooding and secondarily due to other sub-aerial processes (think of physical weathering processes such as freeze-thaw weathering exfoliation and salt crystallisation). Rainwater runs into the extensive basin above the slot canyon sections, picking up speed and sand as it rushes into the narrow passageways. Over time the passageways are eroded away, making the corridors deeper and smoothing hard edges in such a way as to form characteristic ‘flowing’ shapes in the rock.

The Navajo Sandstone was deposited in an aeolian (wind-blown) environment composed of large sand dunes: imagine a sea of sand, or an erg, as it is known scientifically, not dissimilar to the present Sarah desert landscape. The exact age of the Navajo Sandstone is controversial, with dated ages ranging from Triassic to early Jurassic, spanning a time period between 250 million years ago to approximately 175 million years ago. The difficulty in determining the exact age of the unit lies in its lack of age diagnostic fossils. The Navajo Sandstone is not alone in this quandary, dating is a common problem in aeolian sediments.

“The picture was taken during a three week Southwest USA road trip in summer 2012. One of the highlights was the visit to Antelope slot canyon, which is located on Navajo land east of Page, Arizona. The Navajo name for Upper Antelope Canyon is Tsé bighánílíní, which means the place where water runs through rocks,” explains Frederik Tack, an atmospheric scientist from the Belgian Institute for Space Aeronomy and author of today’s Imaggeo on Monday’s photograph.

The erosive processes which form the canyon are still ongoing. There is an elevated risk of flash floods, meaning the canyon can only be visited as part of guide tours.

“The canyon was actually quite crowded which made taking this picture challenging, especially as I wanted to capture the peace and solitude of the landscape,” describes Tack.

The effort was worth it: Waved rocks of Antelope slot canyon was one of the EGU’s 2015 Photo Contest finalists!

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/.

GeoTalk: Meet Andi Rudersdorf, winner of I’m a Geoscientist 2015!

GeoTalk: Meet Andi Rudersdorf, winner of I’m a Geoscientist 2015!

Earlier this year we ran the second I’m a Geoscientist event, an online chat-based game show in which school kids vote for their favourite geoscience communicators. In this week’s GeoTalk, Laura Roberts  talks to Andi Rudersdorf, a neotectonics PhD student and winner of this year’s I’m a Geoscientist…

First, for those who didn’t been following I’m a Geoscientist, can you tell us a little about yourself and what made you decide to take part in the competition?

My name is Andreas Rudersdorf, Andi, and I’m a Geoscientist – studying the neotectonics of an intracontinental basin in the Gobi Desert: the Ejina Basin. This basin lies between the Tibetan Plateau and the Gobi Altai ranges. Currently, I am finishing my PhD thesis at Neotectonics and Natural Hazards | RWTH Aachen University on the integration of geological, geophysical and remote sensing data which I collected to find out when and where tectonic processes shaped the Ejina Basin, where the topography is very flat and where only few prominent geological features document past earthquakes.

I first heard of I’m a Scientist last year when the first geoscience event was advertised and when I was just about to plan my trip to the EGU General Assembly. We have just had an intern in our institute who really liked all the different topics we were working on during that time and I thought it would be great to get in touch with even more pupils and to excite their curiosity in geosciences and to show them what I do.

Have you done any geoscience outreach before?

Our working group in Aachen is quite activeon social media – my colleagues and I are trying to get our friends and followers involved in what we study and publish. So sharing pictures and stories about my work was not new to me. I even suggested to my supervisor that we create a Facebook page to reach out to even more people. However, I guess that the first followers were our students – so the outreach component was rather small at that time…

But there is this great community and blog called paleoseismicity.org, where my friend Christoph and many other authors from the scientific community around the world write about scientific news, recent earthquakes, tsunamis, past and upcoming meetings, field work and recent developments in the fields ofearthquakes and active tectonics. I joined the authors during my Master’s in 2011 and now I’m preparing a weekly section called the Friday links. Of course we aim to reach the scientific community, but we also have lots of readers outside of science.

What inspired you to take part in the competition?

From my blogging experience I knew how good it feels to get feedback when you share your work and how motivating it can be to see others learn new things.

Last year, my supervisor Klaus Reicherter got in touch with school classes where he and my colleagues started a project to teach geology and natural hazards to young pupils. The pupils were really keen to learn about our work and they loved the experiments and field trips they did together. They eventually planned to prepare the first German ShakeOut Day, a school event where earthquake awareness is raised and the right actions during earthquakes are trained. I was impressed by this project and was certain I wanted to take part in a similar event: then the call for the second “I’m a Geoscientist event” started circulating.

What was your toughest question during the competition and how did you respond?

There were quite a few questions that were tough to answer, for example the ones on what happened before or during the big bang, or whether a dress is white and gold or blue and black… In the questions section those questions were great, because I had the time to read a bit on topics outside my field or sometimes think outside the box, and then answer what I learned. During the chats with the students, I just had to learn to say that I didn’t know. And the pupils liked that!

Andi out in the field. Credit: Andreas Rudersdorf

Andi out in the field. Credit: Andreas Rudersdorf

What was the question you enjoyed the most?

I enjoyed all the questions on natural hazards and climate change, because it showed that the pupils were aware of current topics. I loved explaining earthquakes, because I could share how and why I study them and why it is important to learn about the past to understand the present.

You’re the lucky winner of 500 euros, how do you hope to spend it?

I’m still planning to engage more pupils with active faults and earthquakes! But I still have a couple of things to solve before I can break the news…

What’s your top tip for aspiring geoscientists?

Oh, I hope I can give great advice in a couple of years from now. Today I can say that it certainly is fun and rewarding to pursue a career in science. It’s great to answer small scientific questions that may eventually lead to figuring out how to answer the big questions we face today.

 

 

Imaggeo on Mondays: A voyage through scales – The Badlands National Park, South Dakota.

Imaggeo on Mondays: A voyage through scales – The Badlands National Park, South Dakota.

Layer upon layer of sand, clay and silt, cemented together over time to form the sedimentary units of the Badlands National Park in South Dakota, USA. The sediments, delivered by rivers and streams that criss-crossed the landscape, accumulated over a period of millions of years, ranging from the late Cretaceous Period (67 to 75 million years ago) throughout to the Oligocene Epoch (26 to 34 million years ago). Interbedded greyish volcanic ash layers, sandstones deposited in ancient river channels, red fossil soils (palaeosols), and black muds deposited in shallow prehistoric seas are testament to an ever changing landscape.

Fast forward to 500,000 years ago and the landscape was very different. The Cheyenne River diverted the flow of the ancient small streams and rivers down its own river bed, in a geomorphological process called capture. The destructive power of the river dominated over the deposition of sediment. The river cut through the layers of sediments and produced the stunning landscape preserved today.

“The picture was taken in 2009 as I made a road trip with my brother across the United States, from Chicago to San Francisco,” explains Iain Willis, author of today’s Imaggeo on Mondays photograph. “After a long day’s drive, we approached the edge of the Badlands in the late afternoon after turning off route 90. I took the picture of my brother after we’d taken a short walk across a couple of peaks. I didn’t think the picture would be so dramatic as it was actually pretty overcast but as I was setting up the sun was momentarily piercing through. I originally shot in colour but after seeing it in monochrome, it looked far more dramatic.”

Dramatic enough for the judges of this year’s Imaggeo Photo Competition to award Willis the prize for the image which best represented the theme of the 2015 General Assembly: A Voyage through Scales.

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/.

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