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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/.

Imaggeo on Mondays: Late Holocene Fever

Imaggeo on Mondays: Late Holocene Fever

A huge ice fall off the Perito Moreno glacier in the Los Glaciares National Park, southwest Santa Cruz Province, Argentina, was voted one of the three best pictures entered into the EGU’s annual photo contest, by the conference participants at the 2015 General Assembly.

Perito Moreno glacier is one of 48 glaciers feeding into the Southern Patagonia ice field, which combined with the Northern Patagonia ice field, comprise the largest temperate ice mass in the Southern Hemisphere. Like many other mountain glaciers, Perito Moreno, is highly sensitive to climate change. At the surface of a glacier, erosive processes know as ablation, can remove ice from the bulk of the glacial mass. If the ice lost is not replaced in sufficient quantities by rainfall and snow provided by weather systems, the energy balance of the glacier is upset and the glacier starts to shrink. At the glacial surface, the processes of accumulation and ablation, clearly manifest the strict connection between glaciers and climate.

In a recent interview, Bernard Francou, a renowned French glaciologist, explained that glacier depletion in the Andes region has increased dramatically in the second half of the 20th century. In recent decades the glacier recession rates increased at an unprecedented rate when compared to the last the last three centuries. It is estimated that glaciers in this region have lost between 35% and 50% of their area and volume since 1976.

Christian Massari, a hydrology postdoctoral researcher of the Italian National Research Council, says “capturing the precise moment when the large chunk of ice broke off the glacier front was not easy task. It required concentration to patiently wait two hours, on a hot January day, to capture the critical moment.”

You can watch a video of a similar ice fall event, which took place in January 2012, here.

Southern Patagonia Ice Field. Credit: Astronaut photograph ISS038-E-47324 was acquired on February 13, 2014, with a Nikon D3S digital camera using a 65 millimeter lens, and is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by the Expedition 38 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed.

Southern Patagonia Ice Field . Credit: Astronaut photograph ISS038-E-47324 was acquired on February 13, 2014, with a Nikon D3S digital camera using a 65 millimeter lens, and is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by the Expedition 38 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. (Distributed via Nasa Earth Observatory, Image of the Day ).

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: Sunset over the Labrador Sea

Ruby skies and calm waters are the backdrop for this week’s Imaggeo image – one of the ten finalist images in this year’s EGU Photo contest.

 Sunset over the Labrador Sea. Credit: Christof Pearce (distributed via  imaggeo.egu.eu)

Sunset over the Labrador Sea. Credit: Christof Pearce (distributed via imaggeo.egu.eu)

“I took the picture while on a scientific cruise in West Greenland in 2013,” explains Christof Pearce, a postdoctoral researcher at Stockholm University. “We spent most of the time inside the fjord systems around the Greenland capital, Nuuk, but this specific day we were outside on the shelf in the open Labrador Sea. The black dot on the horizon toward the right of the image is a massive iceberg floating in the distance.”

Pearce took part in a research cruise which aimed to obtain high-resolution marine sedimentary records, which would shed light on the geology and past climate of Greenland during the Holocene, the epoch which began 11,700 years ago and continues to the present day.

A total of 12 scientists and students took part in the Danish-Greenlandic-Canadian research cruise in the Godthåbsfjord complex and on the West Greenland shelf. By acquiring cores of the sediments at the bottom of the sea floor, the research team would be able to gather information such as sediment lithology, stable isotopes preserved in fossil foraminifera – sea fairing little creatures – which can yield information about past climates, amongst other data. One of the main research aims was to learn more about the rate at which the Greenland Ice Sheet melted during the Holocene and how this affected local climate conditions and the wider climate system.

“The picture was taken approximately 25 kilometres off the shore of west Greenland coast. In this region the water depth is ca. 500 meters,” describes Pearce. “At this location we deployed a so-called gravity corer and took a 6 meter long sediment core from the ocean floor. Based on radiocarbon measurements – by measuring how much carbon 14 is left in a sample, the age of the sampled units can be known – we now know that these 6 meters correspond to approximately 12000 years of sedimentation, and thus it captures a history of climate and oceanography from the last ice age all the way to present day.”

 

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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