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Imaggeo

Imaggeo on Mondays: The road to nowhere – natural hazards in the Peloponnese

Imaggeo on Mondays: The road to nowhere – natural hazards in the Peloponnese

The Gulf of Corinth, in southern Greece, separates the Peloponnese peninsula from the continental mainland. The structural geology of the region is complex, largely defined by the subduction of the African Plate below the Eurasian Plate (a little to the south).

The Gulf itself is an active extensional marine basin, i.e., one that is pulling open and where sediments accumulate. Sedimentary basins result from the thinning, and therefore sinking, of the underlying crust (though other factors can also come into play). The rifting in the region is relatively new, dating back some five million years, and results in rare but dangerous earthquakes.

The active tectonics result in a plethora of other natural hazards, not only earthquakes.  Minor and major faults crisscross the area and have the potential to trigger landslides, posing a threat to lives and infrastructure. A road, swept away in a landslide, in the northern Peloponnese (along the southern margin of the Corinth rift) is a clear example of the hazard.

“This photo was taken in the Valimi fault block [editor’s note: a section of bedrock bound on either side by faults], east of the Krathis valley. West of this valley, the landscape is characterised by  narrow and deep gorges as the present day rivers cut into the well-consolidated conglomerates deposited during the active extension of the basin,” explains Romain Hemelsdaël, author of this week’s imaggeo on Mondays photograph.

Characteristically, sediments deposited in actively extensional rifts where the Earth’s crust and lithosphere are being pulled apart, as at the Gulf of Corinth, change in size (both horizontally and vertically) and composition. To the east of the Krathis valley, the sediments are being uplifted and are dominated by less competent sandstones and siltstones, as opposed to the conglomerates found in the Valimi fault block.

“The present landscape along this part of the rift margin forms large valleys covered by active landslides,” clarifies Romain. “In this photograph, the road was initially constructed directly on silts which were deposited by lakes and rivers. Up the hill, a temporary track currently replaces the road but this track still remains within an active landslide.”

 

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: what corals can tell us about past climate change

Imaggeo on Mondays: what corals can tell us about past climate change

Reconstructing past climates is a tricky task at the best of times. It requires an ample data set and a good understanding of proxies. Add into the mix some underwater fieldwork and the challenge got a whole lot harder! In today’s Imaggeo on Monday’s post, Isaac Kerlow explains how information locked in corals can tell the story of past climates and how important it is, not only to carry out the research, but to communicate the results to the public! If you stick with this post until the end you’ll be rewarded with a super informative video too!

One of the main science communication initiatives at the Earth Observatory of Singapore (EOS) is about producing short films that showcase the scientific research of the principal investigators. The collection of films created by the EOS Art+Media group is called the “Knowledge Capsules” and they are free to view and download on the internet. On this occasion the filmmaking team travelled to Checheng, Southern Taiwan, to document and explain the field methods of the Marine Geochemistry team.

Creating a successful science film for a mainstream audience requires an understanding of the scientists’ methods, theories and goals. During principal photography that takes place during expeditions the filmmaking team needs to stay a step ahead of the game in order to capture the critical moments such as this image where Dr. Nathalie Goodkin passes a sample of Porites coral (a type of stony, finger-like, coral) to a scientist aboard the research vessel.

The Marine Geochemistry team at EOS investigates Earth’s climate history through the study of corals. This region is where the Kuroshio Current intrudes into the South China Sea. The team extracted samples of the Porites coral species that are approximately 300 to 500 years old, as well as seawater in which these corals grow. Because the chemical composition of corals depends on the seawater in which they grow, analysing the coral samples can give an indication of the temperature and salinity of the surrounding seawater. With these results, the team is able to reconstruct global climate systems throughout several centuries.

By Isaac Kerlow, Earth Observatory of Singapore

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: Get involved!

Imaggeo on Mondays: Get involved!

Today’s featured image is a throw back to our 2016 General Assembly! Did you enjoy this year’s 619 unique scientific sessions and 321 side events at conference? Did you know that EGU members and conference attendees can play an active role in shaping the scientific programme of the conference? It is super easy! You can suggest a session (with conveners and description), and/or modifications to the existing skeleton programme sessions. So, if you’ve got a great idea for a session for the 2017 conference, be it oral, poster or PICO, be sure to submit it before this Friday, 9th September!

But helping us prepare the next General Assembly is not the only way you can have a say in EGU activities over the coming weeks. The EGU’s Autumn Elections are coming up too and we need your help to identify suitable candidates for vacancies as Division Presidents and Treasurer. Until the 15th of September you can nominate candidates for the positions. Think you’ve got it takes to have a go at the role? Then you are also welcome to nominate yourself!

Finally, did you know that as part of its ‘science for policy’ programme, the EGU is creating a database to identify expertise within the Union that can be used in policy-related events of geoscientific relevance, for example, submitting response texts to the European Parliament’s calls for expert advice? Please register if you have an interest in policy and want to participate more in the science policy process. By registering for this database you may be emailed from time to time with requests to respond to specific events.

For other EGU related news, why not visit our news pages, or catch up on the latest via our monthly newsletter (which you can receive direct to your inbox, simply sig up!)?

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: Living flows

Imaggeo on Mondays: Living flows

There are handful true wildernesses left on the planet. Only a few, far flung corners, of the globe remain truly remote and unspoilt. To explore and experience untouched landscapes you might find yourself making the journey to the dunes in Sossuvlei in Namibia, or to the salty plain of the Salar Uyuni in Bolivia. But it’s not necessary to travel so far to discover an area where humans have, so far, left little mark. One of the last wilds is right here in Europe, in the northern territories of Sweden. Today’s spectacular photograph of the Laitaure delta is brought to you by Marc Girons Lopez, one of the winners of the 2016 edition of the EGU’s Photo Contest!

The photograph shows a part of the Laitaure delta, at the entrance of Sarek National Park (Northern Sweden). Sarek is one of the oldest national parks in Europe and it is often considered to be one of the last wild areas in Europe. The Sami people, however, have traditionally used these lands.

This delta is formed by the Rapa River when it flows into Lake Laitaure. The Rapa River springs from the Sarektjåkkå glacier and is fed by over thirty glaciers. The specific flow of the Rapa River — the ratio between its flow and the area of its catchment — is the highest in Sweden. The magnitude of the flow has strong seasonal fluctuations which are reflected in the sediment transport, which can be as high as 10,000 tons per day during the summer. This heavy sediment load gives the river its characteristics greyish colour. The different colours in the backwater zones may be produced by dissolved organic matter from decomposing vegetation.

The delta in this area is flanked by  patches of montane forests along the river banks in an area otherwise covered by marshes. Regarding the fauna, according to Wikipedia the Eurasian teal, the Eurasian wigeon, the greater scaup, the red-breasted merganser, the sedge warbler and the common reed bunting are common in the Laitaure delta.

By Marc Girons Lopez, researcher at the Centre for Natural Disaster Science, Uppsala University

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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