Archive | May, 2011

Imaggeo on Mondays: Rhosilli Beach

30 May

Rosilli Beach

An image of Rhosilli beach in Gower, Swansea, Wales. Image by Jorge Mataix-Solera, distributed by EGU under a Creative Commons licence.

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

Grímsvötn eruption and the importance of research

26 May

This perspective on the Grímsvötn eruption and volcanic activity, ash transport and ash detection comes from Dr Mike Burton. Dr Burton is a Senior Researcher at the Istituto Nazionale di Geofisica e Vulcanologia, Pisa, Italy. His research includes utilising novel gas and video imaging techniques to better understand volcanic processes. At the EGU General Assembly 2011, he convened GMPV5 Monitoring and observations of active volcanoes using in-situ and remote sensing techniques along with Thomas Staudacher , Jurgen Neuberg , Hugo Delgado Granados, and Alessandro Bonaccorso.”

Once more with feeling

Just a little more than a year after the eruption of Eyjafalla another Icelandic volcano, Grímsvötn, is injecting volcanic ash and gas high into the atmosphere, disrupting air traffic over Europe. This time the eruption has been much more intense, with an eruption column reaching up to 20 km in the initial stages of the activity. Fortunately the eruption has swiftly waned, and at the time of writing eruptive activity has reduced greatly. Nevertheless, the volcanic ash already injected into the upper troposphere will continue to circulate for several days before it becomes so dilute that it no longer poses a risk to aviation, and we see that airports in northern Europe have had to close as air traffic restrictions are put in place. Such events remind us of the enormous importance that European level research in volcanic activity, ash transport and ash detection has for improving our ability to both understand and react to rapidly changing events.

Volcanic eruptions, while challenging to predict, are produced from well-known areas, particularly in Iceland where frequent eruptions have been extremely well-documented and well-observed for many years. This allows statistical analysis of the frequency of such events and preparation for their eventuality. Unfortunately, while scientists from many nations have lobbied for increased resources to deal with this issue, governments have been slow to act, but the recent eruptions on Iceland and their consequent impact on the European economy through disruption to air traffic has produced an unprecedented focus on this issue. This focus was exemplified at the recent EGU General Assembly in Vienna in April where a series of well-attended sessions focussed on the science of the 2010 eruption, modelling of the ash dispersal and analysis of satellite and lidar measurements of ash. It is clear that further research is a fundamental priority for Europe in order to produce improving responses to the inevitable eruptions which will occur in the future, not just from Iceland, but also from Italy and potentially the Azores and Canary Islands as well.

Grimsvötn eruption observations from the field

26 May

This description on the Grímsvötn eruption comes from Dr Olgeir Sigmarsson, an Icelandic volcanologist who is Director of Research, CNRS at the Laboratoire Magmas et Volcans, Observatoire de Physique du Globe de Clermont-Ferrand. He also works at the Institute of Earth Sciences, University of Iceland. His research is on geochemistry: genesis, chronology and evolution of magma. Dr Sigmarsson has been collecting tephra samples from the glacier in the field near to the Grimsvötn volcano and the below contains information from his Icelandic colleagues.

The Grimsvötn eruption 2011 has stopped for the time being. It started around 19:00 last Saturday (21 May) and it’s eruption column rose to approximately 17 km during the first night. It thus penetrated into the stratosphere, observed for the first time for an eruption from Grimsvötn volcano. Grimsvötn is a complex caldera structure covered by the largest ice-cap in Europe, namely Vatnajökull. The high-temperature area melts the floating ice on the subglacial lake that occasionally is lifted from the bedrock by the water mass, emptying the lake and creating glacier bursts, better known as jökulhlaup. Such pressure release generates more vigorous boiling in the geothermal system and sometimes may act as a trigger for an eruption (such as in the 2004 eruption). Fortunately the last jökulhlaup occurred last autumn, leaving little water in the subglacial caldera lake.

The actual eruption emitted approximately 10-20 tons/sec of tephra during the first day but declined rapidly and on the 24th May the column rose only to 3 km height during occasional explosions. On the 4th day, only vapour explosions with little solid material were observed at the crater close to the south wall of the caldera. Tephra fall was noticed all over Iceland (with the exception of the Westfjord peninsula) with grain-size having approximately 10% finer than 10 micronmeters and 50% finer than 50 micronmeters. Based on preliminary measured tephra thickness, the volume is crudely estimated as ½ cubic km of freshly fallen tephra.

Seismicity and deformation indicate a shallow magma source and the magma is basaltic of quartz-normatve tholeiite composition similar to all historic tephra. However, since the Laki eruption, increased concentrations of incompatible elements have increased with time suggesting a closed-system behaviour with minimal deeper input of more primitive magma. The fact the actual eruption was very explosive in the beginning and rose above the tropopause indicate either (1) a more evolved basaltic magma than before or (2) a deeper gas-rich magma entering into the plumbing system beneath Grimsvötn caldera. The first possibility would suggest that the volcano is evolving towards more evolved magma with higher gas content
and potential high explosivity, whereas the second possibility suggests a changing feeding system with renewal of fresh basalt from depth. These two possibilities can be distinguished by precise trace element analysis of the actual tephra.

Grímsvötn volcanic eruption

24 May

The Grímsvötn volcano in Iceland started erupting on 21 May 2011. Icelandic airspace was closed soon after with flights now being affected in the United Kingdom.

This post brings together some good sources of imagery and information. These sources are not endorsed by the European Geosciences Union, more a resource letting people know what is available. If you know of a good source of information, let us know in the comments or email us.

The UK Met Office is responsible for ash cloud monitoring for Northern European airspace. Their pages include warnings issues and maps showing predicted ash cloud movements.

NASA Earth Observatoryimagery is available (such as below). Including commentary on the image.

Grímsvötn Modis Natural-Color Image (NASA, 2011)

The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) has imagery and animcationsfrom various satellites, including real-time images. An example is shown below.

Grímsvötn Altitude Imagery, copyright EUMETSAT (2011)

Grímsvötn Altitude Imagery, copyright EUMETSAT (2011)

News and information from Iceland itself is available from the Iceland Met Office and the University of Iceland Institute of Earth Sciences which has an Eruption in Grímsvötn 2011 page, which contains photos, satellite imagery, GPS time series, chemical composition information, and relevant scientific publications alongside status reports.

Relevant abstracts about the Grímsvötn volcano that were presented at the EGU General Assembly 2011 are Óladóttir et al., Thordarson et al., and Magnússon et al..

Imaggeo on Mondays: Water Angel

23 May

Water Angel

A “water angel” seems to appear in the upper part of the Trift Glacier Lake in the Swiss Alps. This image was a finalist in the EGU GA 2011 Photo Competition.

Image by Romain Schläppy, distributed by EGU under a Creative Commons licence.

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

EGU GA 2011 Feedback Survey: please complete

20 May

The EGU General Assembly 2011 was again a great success with 4,333 oral and 8,439 poster presentations in a dozen union wide and 520 disciplinary sessions, along with townhall meetings, short courses, splinter meetings, etc. At the conference 10,725 scientists from 96 countries participated, of which 28% were students, 15,000 copies of EGU Today distributed, keen media presence and reporting, and thousands of visits to the webstreams as well as to the EGU 2011 blog. We thank all of you very much for your attendance and your active contribution to this great event.

Last year, we had a GA feedback form and asked 24 questions. We received 1,819 responses (results), which were examined carefully and helped us in many important decisions.

This year, we again would like to ask EGU GA participants to take 10-15 minutes of time to complete the short questionnaire here. If you an abstract accepted for the General Assembly 2011 but did not attend we’re also interested in your views.

Your input is genuinely invaluable in shaping the EGU GA 2012, to be held 22–27 April 2012, Vienna, Austria. Thank you very much in advance!

Meet the EGU at EAGE in Vienna

18 May

Are you going to European Assoication of Geoscientists and Engineers 73rd Conference23-26th May 2011? If so please visit the EGU at Booth 2450 in Hall B, Reed Messe Wien and meet the executive secretary, Philippe Courtial.

Imaggeo on Mondays: Carboniferous arachnid

16 May

Carboniferous arachnid Eophrynus prestvicii

A 3D reconstruction of the 312 million year old arachnid Eophrynus prestvicii, from a CT scan of the fossil. Arachnids such as this – members of the Trigonotarbida – were amongst the first terrestrial predators. This image was one of the finalists in the EGU GA 2011 Photo Competition. To find out more about this image, see Friday’s post: 3D reconstructions of ancient arachnids.

Image by Russell Garwood, distributed by EGU under a Creative Commons licence.

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

3D reconstructions of ancient arachnids

13 May

One of the finalists in the European Geosciences Union General Assembly 2011 Photo Competition was an image from Russell Garwood. This image was not a traditional photograph but a 3D reconstruction of a 312 million year old arachnid Eophrynus prestvicii, from a CT scan of the fossil. The image itself will be the feature for the Imaggeo Mondays post on 16th May. However, due to the different nature of the image Russell has put together a brief description of the image and how it was created.

Russell Garwood is a invertebrate palaeontologist who is currently based at the Natural History Museum in London. He has a personal research webpage. He presented work on Tomographic reconstruction in palaeontology at the EGU General Assembly 2011.

Many Carboniferous fossils, such as this specimen of Eophrynus prestvicii, are found as three-dimensional voids within siderite (iron carbonate) concretions. This means that traditional palaeontological techniques – for example, splitting the rock open and inspecting the surface revealed – result in incomplete data recovery. Such limitations can be overcome with the aid of x-ray micro-tomography (XMT), a high-resolution form of CT scanning. This remarkably complete specimen of Eophrynus prestvicii was first described in 1871, and was used three years ago to test the applicability of XMT to siderite-hosted fossils, resulting in this image. The XMT provided a slice-based (tomographic) dataset. Custom software (called SPIERS) was used to threshold and clean each slice, and then define regions of interest. This allowed the limbs to be rendered separately and coloured. The image you see was then created by outputting a finished ‘virtual fossil’ as a mesh, and using the open source ray-tracer Blender to model it under user-defined lighting conditions. The reconstruction reveals an arachnid with heavy armour – presumably a defensive adaptation – and also showed, for the first time, the mouthparts (or chelicerae) of the species. Representatives of the order to which this species belongs, the Trigonotarbida, were amongst the earliest terrestrial predators. While this Carboniferous (~311 million year old) specimen postdates these early examples of the order by many millions of years, it too was a predator, probably running down its prey with its long limbs. The same techniques has now been applied to a wide range of the arthropods living in these Carboniferous coal forests. The image first appeared in the publication Garwood et al. (2009). A more comprehensive introduction to these techniques can be found in the publication Garwood et al. (2010).

Garwood, R.J., Dunlop, J.A. & Sutton, M.D. 2009. High-fidelity X-ray micro-tomography reconstruction of siderite-hosted Carboniferous arachnids. Biology Letters, 5(6):841-844. doi: 10.1098/rsbl.2009.0464 link, , requires subscription for full article]
Garwood, R.J., Rahman, I.A. & Sutton, M.D. 2010. From clergymen to computers – the advent of virtual palaeontology. Geology Today, 26(3):96-100.
doi: 10.1111/j.1365-2451.2010.00753.x link, requires subscription for full article

Geocinema films available online (3/3)

13 May

This is the last in a series of posts (Part 1, Part 2) with descriptions and online locations of Geocinema films. A film’s inclusion in the Geocinema does not mean that EGU endorses any opinions expressed in the film. If you have a film you’d like to submit for the Geocinema at the EGU GA 2012 look out for the call.

Inspection Exercise in Jordan, 6 mins [Online]
This film discusses a simulated on-site inspection exercise that was carried out in regards to monitoring compliance of the Comprehensive Nuclear-Test-Ban Treaty.

Listening for Nuclear Noise, 5 mins [Online]
This film discusses some of the technology used to monitor compliance of the Comprehensive Nuclear-Test-Ban Treaty. In particular the technology that goes into a typical infrasound monitoring station, this particular station is located in the Bavarian Forest.

EISCAT_3D, our window to geospace, 7 min [Online]
FFAB:UK, together with EISCAT Scientific Association, has produced an information film about the EISCAT_3D project. It explains the background, the concept, and some of the new science that will be possible when the EISCAT_3D facilities are completed.

Earth System Trailer, 7 mins [Online]
Trailer for a documentary feature about climate, what the scientists know, what is unknown and what needs to be done to improve our stewardship of this planet. ESS trailer explores the need for next generation supercomputing to develop climate models which are a prerequisite to predicting climate change with scientific certainty.

SNORTEX – Snow reflectance transition experiment, 10 mins [Online]
The video introduces the SNORTEX (Snow Reflectance Transition Experiment) campaign taken place in Sodankylä (lat. 67.4N), Finland, in spring 2009. An overview on the background, objectives and expected scientific outcome of the campaign is given. Experimental methods and equipment employed in ground-based and air-borne measurements of snow reflectance and characterization of snow properties are presented.

Science@ESA: Solar System, Siblings of Earth and the Moon and Titan, 54 mins total [Online, with others]
In these Science@ESA vodcasts Rebecca Barnes looks at the Solar System. We’ll discover the scale and structure of the Solar System, find out why we explore it and introduce the European missions launched on a quest to further investigate our local celestial neighbourhood. We’ll look at two of the terrestrial planets: Venus and Mars, explore their similarities and differences to Earth and find out about the European missions that are helping to unravel their mysteries. Finally we’ll look at the Earth’s Moon and Titan, two very different natural satellites in our Solar System, and find out about the two ESA missions that have explored them.

Huygens probe landing on Earthlike world, 5 mins [Online]
This short film documents spectacular descent of ESA’s Huygens on Saturn’s giant moon Titan.