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Imaggeo on Mondays: A massive slump

1 Sep

One of the regions that has experienced most warming over the second half of the 20th century is the Potter Peninsula on King George Island in Antartica. It is here that Marc Oliva and his collaborators are studying what the effects of the warming conditions on the geomorphological processes prevailing in these environments.

“Permafrost is present almost down to sea level in the South Shetland Islands, in Maritime Antarctica” says Marc, “in some recent deglaciated environments in this archipelago, the presence of permafrost favours very active paraglacial processes”.

Permafrost is defined as the ground that remains frozen for periods longer than two consecutive years and constitutes a key component of the Cryosphere. However, it is not fully understood how it reacts to climate variability. In this sense, there is an on-going effort to improve our knowledge on these topics by carrying out long–term monitoring of permafrost, as well as of geomorphological processes, in order to better understand the response of the terrestrial ecosystems to recent warming trends.

This weeks’ Imaggeo on Mondays picture shows a massive slump and the exposed permafrost in the shoreline of a lake in Potter Peninsula (King George Island, Maritime Antarctica). Following the deglaciation of this ice-free area paraglacial processes are very active transferring unconsolidated sediments down-slope to the lake.

Slump-permafrost, Potter Peninsula, Antarctica. (Credit: Marc Oliva via imaggeo.egu.eu)

Slump-permafrost, Potter Peninsula, Antarctica. (Credit: Marc Oliva via imaggeo.egu.eu)

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.

Imaggeo on Mondays: Beneath a star-studded sky

4 Aug

Marco Matteucci captured this image of the night sky on the slopes of Mount Rosa, the second tallest peak in Alps. Mount Rosa straddles the border between southern Switzerland and Italy the pink mountain’s name comes from the Franco-Provençal word rouése, meaning glacier. Much off the Swiss side of the mountain is enveloped in the ice of Gorner Glacier, the second largest glacier in the Alps. On the Italian side, lies Belvedere Glacier, which is fed by the snow that falls on Mount Rosa.

Mount Rosa ridge, Valle d'Aosta, Italy. (Credit: Marco Matteucci via imaggeo.egu.eu)

Mount Rosa ridge, Valle d’Aosta, Italy. (Credit: Marco Matteucci via imaggeo.egu.eu)

Wish you could capture images like this yourself? You can! Take a look at this brief guide to space photography for some hints and tips. 

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.

Imaggeo on Mondays: Entering a frozen world

21 Jul

Dmitry Vlasov, a PhD Student and junior scientist from Lomonosov Moscow State University, brings us this week’s Imaggeo on Mondays. He shares his experience of taking part in a student scientific society expedition to Lake Baikal.

This picture shows icy shores of Lake Baikal – a UNESCO World Heritage Site and the world’s largest natural freshwater reservoir (containing about one fifth of Earth’s unfrozen surface freshwater). It is also the deepest lake on our planet (1,642 m).

The icy shores of Lake Baikal. (Credit: Dmitry Vlasov, via imaggeo.egu.eu)

The icy shores of Lake Baikal. (Credit: Dmitry Vlasov, via imaggeo.egu.eu)

The aim of the expedition was to do an eco-geochemical assessment of the environment in and around Ulan-Ude (the capital of Republic of Buryatia). Snow samples were collected all around the city to determine their chemical composition and the concentrations of different chemical elements present in the snowpack. We also studied the isotopic composition of snow to help find the sites where air masses form.

Weather-wise, we were lucky – according to locals this winter was a warm and snowy one. The temperature was (only!) -25 to -33 degrees Celsius. Times were tough when strong, cold and piercing winds froze our hands and faces.

To find out the impact of transport and industry on the snow’s chemical composition within the city, we took background snow samples at different distances and in and around it. One such area was set to the northeast of the city, close to the Turka and Goryachinsk settlements across the notch from Ulan-Ude. This photo was taken in that exact spot. It took about 2.5 hours to make the 170 km journey from Ulan-Ude by car, but we didn’t regret it. The scenery was amazing! The cover of ice over the lake sparkled bright blue, despite being exceptionally transparent. Because of the water’s choppy nature, ice on the Lake Baikal often cracks and billows to form a chain of miniature ice mountains, alternated with relatively smooth ice plains. I’d never seen anything like this before.

All the participants were very excited about expedition – it showed the students different sides of scientific life: work in rather hard weather conditions, analytical lab studies, route planning and of course the breathtaking beauty and outstanding power of nature.

By Dmitry Vlasov, PhD Student and junior scientist, Lomonosov Moscow State University

Acknowledgement:

The expedition was carried out with the financial support of the Russian Geographical Society and the Russian Foundation for Basic Research (project № 13-05-41191 and project RGS “Complex Expedition Selenga-Baikal”).

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.

Imaggeo on Mondays: Shaken, not stirred – sediment shows signs of past earthquakes

23 Jun

Nore Praet, a PhD student from Ghent University in Belgium, brings us this week’s Imaggeo on Mondays. She sets the scene for an investigation into past earthquakes and explains how peering through a lake’s icy surface and its murky waters, and into the sediment below can help scientists find out more about the impact of earthquakes in the future…

Early this year, I set off with a group of scientists (including Koen De Rycker, Maarten Van Daele and Philipp Kempf) from the Renard Centre of Marine Geology to conduct fieldwork in South-Central Alaska. The reason for our stay was the search for past megathrust earthquakes (earthquakes produced by the subduction of an oceanic tectonic plate under a continental plate), which had an unusually high magnitude and destructive power.

The most recent Alaskan megathrust earthquake was the Great Alaskan Earthquake in 1964, which represents the second largest earthquake ever instrumentally recorded (9.2 on the moment magnitude scale). In order to have an estimate when such a large earthquake may strike again, we need to study the recurrence pattern of past earthquakes. Since megathrust earthquakes typically have recurrence periods of several centuries, historical archives will not suffice. This is where natural archives, like lake sediments, come in. These records have the advantage of going much further back in time, and they are what brought us to Alaska’s Eklutna Lake.

Zooming in on some individual ice crystal aggregates (few centimeters across) and geometric frost patterns on the frozen surface of Eklutna Lake in Southern Alaska. (Credit: Nore Praet via imaggeo.egu.eu)

Zooming in on individual ice crystal aggregates (few centimeters across) and geometric frost patterns on the frozen surface of Eklutna Lake, Alaska. (Credit: Nore Praet via imaggeo.egu.eu)

Lake sediments can contain very distinct earthquake traces because seismic shaking produces underwater landslides that leave well-defined sediment deposits in the lake basin.

Long sediment cores, extending some 15 metres through these deposits, make it possible to construct a palaeoseismic record. From this we can make an estimate of the recurrence rate of megathrust earthquakes. This will be crucial for understanding seismic hazard in South-Central Alaska and, in particular, in the densely populated city of Anchorage.

This photo, taken in early February, captured the moment where we officially started the fieldwork, after checking the thickness of the ice and its stability.

The constant struggle with the almighty Alaskan cryosphere was the real common theme during the fieldwork. The freezing cold, together with ice formation on the coring equipment, seriously hampered the efficiency of the coring operation. It took some time to accept these conditions and adjust to the demanding laws of this harsh wilderness, but once you are willing to invest the energy into working here, every day nature surprises you with her astonishing beauty.

By Nore Praet, Ghent University

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.

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