Author Archives: John A. Stevenson

Gas, not ice, makes subglacial rhyolite explode

A recent study by Jacqui Owen (Lancaster University), Hugh Tuffen and Dave McGarvie shows that the explosivity of a subglacial rhyolite eruption is determined while the magma is still deep beneath the ground. Rhyolite is a particularly thick and gloopy … Continue reading

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UK Environment Advisor’s talk on climate change

If you are in any doubt that climate change is the biggest issue of our time, then I highly recommend watching the talk given by Prof Robert Watson, the former Chief Scientific Advisor to the UK’s Department for Environment, Food … Continue reading

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Easily change coordinate projection systems in Python with pyproj

Python is an easy-to-use programming language which, thanks to a growing number of cool extension modules, is really taking off in the world of scientific data handling.  The Proj4 libraries are a set of programs for performing coordinate system transformations.  … Continue reading

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A visual estimate of the proportions of mixtures: pumice vs. lithics

When a volcano erupts explosively, the tephra that comes out is a mixture of material that was molten at the time and bits of other old, cold rock that happened to get caught up in the blast.  These are referred … Continue reading

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Ten swimming pools of travel chaos

An article published this week reveals the volume, grainsize and eruption rate characteristics of the tephra (volcanic ash, pumice and other materials) erupted during the eruption of Eyjafjallajökull in 2010.  This information is important because these are the inputs needed … Continue reading

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Iceland horse fun

Ever the practical joker, Dobbin thought it would be hilarious to rohypnol the water trough…

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Fieldwork update: Progress map, river crossings and bulldozers

This is a quick post to let you know how the fieldwork is going so far. Sampling the distal deposits of Hekla’s largest eruptions since the ice age The aim of my project is to sample the deposits of the … Continue reading

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Glacier of the mountains of the islands

Everyone has heard of Eyjafjallajökull. Not everyone can pronounce it. It is almost as infamous for its long name than for the travel disruption that it caused. But the name is much easier when you break it down into its … Continue reading

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On the geology of Prometheus

Contrary to the advice of pretty much everyone that has seen it, I went to see Prometheus at the weekend. A big reason for going was that I knew they had filmed part of it in Iceland. I had seen … Continue reading

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Insight into climate debate at the Volcanism and the Atmosphere conference

Last week was the American Geophysical Union (AGU) Chapman Conference on Volcanism and the Atmosphere in Selfoss, Iceland. It covered topics such as explosive eruptions, satellite detection of volcanic ash, aviation hazards and climate modelling. Unlike larger meetings, where sessions … Continue reading

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