Here are some of my highlights from last week’s European Geoscience Union conference. These were presentations dirty hailstones formed in subglacial volcanic eruptions, a workshop on social media and blogging in geosciences, a splinter meeting on open source software in geoscience and The Great Debate on shale gas/fracking.
Dirty volcanic hail
Þórður (Thordur) Arason presented the first detailed study of volcanic ash-filled hailstones. These are closely related to subglacial volcanic eruptions, such the two most-recent Icelandic events. He studied examples from the deposits of the May 2011 Grímsvötn eruption that he collected, still frozen, from layers between the pumice and ash deposits that formed during the eruption, high on the Vatnajökull glacier
These ice-cemented spheres of volcanic ash formed during the Grímsvötn eruption in Iceland in May 2011, and are similar to the hailstones described at EGU 2013. I took this photo when I visited the crater area three months later. It was an adventurous trip, involving monster trucks and crevasses. Click the image to read more.
Arason measured the sizes of the hailstones (mostly 1-2 mm) from close-up photographs. He weighed a big rectangular block of them, then allowed it to melt so that he could collect that ash grains inside. The hailstones contained 15-40% ash, with grains from a few microns to over 1 mm in diameter.
Quantifying the contents of the hailstones is important for a number of reasons. Firstly, by mixing ash grains with ice, you change the particle size and optical properties of the grains. Arason demonstrated how this can lead to huge errors in measurements of ash plumes made by radar, and ice-covered ash is a problem for satellite measurements, too. Secondly, by trapping very fine ash, the hailstones stop it drifting off downwind towards Europe. These processes will be included in the next generation of computer models for ash dispersal.
It must take a lot of water to make so many hailstones. Thanks to Magnús Tumi Guðmundsson, we have a pretty good idea of how much. In his talk, he described changes in the Vatnajökull glacier around the eruption site. There is a permanent subglacial lake at Grímsvötn that periodically releases meltwater floods (jökulhlaups) out onto the lowlands, so Icelanders have detailed maps of the ice surface and of the bedrock beneath.
In this case, the volume of missing ice is equivalent to the water that went up with the plume, because there was no jökulhlaup during the eruption. Guðmundsson found this volume was around 0.1 km3, which is about one seventh of the volume of tephra (pumice, ash and rock debris) that were produced during the eruption. Averaging all this water over the 4 days when the eruption was most powerful gives a discharge of about 290 m3s-1. This is equivalent to a fountain with 10% of the discharge of the Nile, shooting straight up into the air.
Social media and blogging workshop
The social media and blogging workshop panel included the geobloggers and tweeters Jon Tennant (@protohedgehog), Laura Roberts (@LauRob85), James King (@DrAeolus) and Dave Petley (@davepetley) and was chaired by EGU social media officer Sara Mynott (@EuroGeosciences). They discussed the advantages of Twitter (finding breaking news first; access to well-informed people on any topic; making contacts from all over the world), and of blogging (explain things in more detail than traditional media are interested in; raise your academic profile; become a contact point for journalists interested in your subject).
I was interested to hear that some PhD student bloggers are writing on blogs that their supervisors had set up but didn’t have time to write themselves. It was also interesting that some climate scientists are discouraged from blogging by the abuse that they receive in their comments from climate change deniers.
Dave Petley is a professor in the Institute of Hazard, Risk and Resilience at Durham University and runs The Landslide Blog, hosted by the American Geophysical Union. By professor, I mean in the UK senior-academic-who-runs-his-own-research-group sense of the word, as opposed to the US academic-with-a-permanent-(tenured)-position sense. His story was especially convincing. In the six years since he began his blog, he has seen traffic to the site gradually increase to over 1,000 visitors per day. Over the same period, he showed how citations to his papers had also risen sharply and said he now receives many more invites to meetings and conferences.
Dave also described how a blog post that he wrote about a fatal flash flood in Nepal became the global focal point for people looking for information on the event, including Nepali journalists and visiting tourists. An ex-Soviet military pilot provided YouTube footage showing that the cause was a landslide from the mountain Annapurna IV, and NASA contributed satellite imagery. The results of the study will be written up as a scientific publication.
I’ve found a similar benefit from blogging. In 2011, I wrote a post asking members of the UK public to collect ash fall from the eruption of the Grímsvötn eruption, and posted the request on Twitter. We received over 130 samples from across the country, and the results, which include a map of where ash was found, will be published in the Journal of Applied Volcanology in the next few weeks.
Free and Open Source Software (FOSS) in the Geosciences
Following an oversubscribed splinter meeting last year, the profile of Free and Open Source Software in the Geosciences continues to increase. This year featured another Splinter Meeting and a dedicated session featuring both talks and posters. I made it along to part of the Splinter Meeting, which highlighted the benefits of using free/open source software and displayed the huge and growing range of tools that are available.
The panel highlighted that a great way to test some of these tools out is to download the OSGeoLive DVD, which contains the latest versions of over 50 different packages. Simply fire up your machine with the disk in the drive and it will boot into a fully-functioning Linux desktop with all the software installed and ready to go. When you are done playing, shut the machine down and take the disk back out. Your original operating system will be untouched.
The OSGeo-Live DVD is a great way to try out open source GIS software
The arguments for open source in science were strengthened recently by editorial in the journal Nature, and by articles in the journal Science. The Scientific Method rests on experiments being tested by different people. Many advances in science come from computer modelling, but if scientists do not publish their code, how can others test it?
Related to this were issues about where the code should be stored. Ideally, the code would become citable item so that scientists get recognition when others use it. Reproducibility of results was also discussed. Using open source software, as opposed to proprietary code whose internal workings are a commercial secret, ensures that the exact versions of software used will always be available to those attempting to reproduce a result.
The Great Debate – Shale gas: to frack or not to frack
Hydraulic fracturing, also known as fracking, involves pumping high-pressure water into underground rocks, forcing them to crack and to release previously-inaccesible natural gas. It is a controversial process, and the EGU Great Debate was advertised as an opportunity for top scientists do discuss the pros and cons of getting fossil fuels in this way. These are summarised nicely in the session outline.
I was excited to watch this debate taking place in front of a technical audience, looking forward to getting into the details of charts of production rates in wells, descriptions of changes to rock properties during fracking and projections of future changes in global gas prices. Many others were, too, and it was standing room only. Disappointingly, the whole event turned out to be very thin on data. One guy said that shale gas would all be gone in fewer than 20 years, then another said that it would last more than 100. Neither presented any evidence for where those numbers had come from. A wasted opportunity, I think.
[Since getting home, I’ve found Matt Herod’s write-up of the debate. It seems that he was also disappointed by lack of hard data. His post contains a link to the video of the debate and some good background information on fracking in general].
Pingback: Grímsvötn 2011 (Part 2): Effects on aviation of the biggest Icelandic eruption since Katla 1918 | Volcan01010