‘Extreme’ sedimentation event associated with Icelandic volcanic eruption
The ongoing eruption of the Eyjafjallajokull volcano in Iceland is making big news because of the effect of the ash on flights in northern Europe. My two main sources of information, the Eruptions blog and The Volcanism Blog, both do a great job of not only relaying up-to-date information but providing tons of links to various scientific organizations reacting to and studying this geologic event.
I wanted to highlight this video I came across showing a jökulhlaup in process. A jökulhlaup is the Icelandic word for a glacial outburst flood that is commonly generated by subglacial melting during a volcanic eruption. I think the term is also used for similar magnitude flood events from glacial lakes when an ice (or debris) dam abruptly fails.
I also want to point out the train of waves from 0:46-0:57 seconds in the video. I’m not sure — don’t quote me on this — but those appear to be associated with supercritical flow (most are introduced to this concept discussing the formation of antidunes). Perhaps a train of hydraulic jumps or some kind of cyclic step process? A quick search came across this paper interpreting supercritical flow based on the sedimentary deposits from a jökulhlaup in 1918 in Iceland.