< Norfolk Volcano

Making a volcano: why we need to get topography right

< Norfolk Volcano

Making a volcano: why we need to get topography right

I’m starting to feel like an old fart. In this Google-Earth-enabled, saved-by-SatNav world I sometimes wonder if there is any space left for map geeks like me. I’ve spent rather too much of my adult life staring at contours for one reason or another. I love it.

We all  love landscape and topography, however. This powers our drive to find ways to represent landscapes that captures some of the excitement of being out and about in them. When it comes to clarity, precision and accuracy (often needed for scientific purposes) it ‘s still hard to beat the old-fashioned contour.

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Photo taken by Jon Stone. This volcano (Tungurahua) had a sudden explosion on the 14th of July that sent pyroclastic density currents down some of its beautiful valleys, trashing them.

Volcanoes usually dominate any landscape they occupy. They are the landscape and they destroy and control it; occasionally on timescales faster than you can choke down your morning cornflakes. The pathways of many of the vast billowing clouds of hot ash, gas and scorching rock that pile out from the mouths of volcanoes are controlled by the topography; filling, scraping and changing it as they go.

Just as there are many and varied types of volcanic activity (lava flows, pyroclastic density currents, explosions big and small, lahars) there are many brilliant types of volcanoes, their topography providing tell-tale signs of the processes that carved them. Volcanoes can get too big and unstable for their unconsolidated, tectonically active boots too, collapsing and losing entire sides only to build them up again with more material another day. And, yes, just sometimes they really can ‘blow their tops’ leaving toothy gaps in the landscape for all to admire.

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The classic volcano that lost its top (and side). National Geographic photograph of tourists standing before the volcano as it is now admiring the ‘before’ image of Mt St Helens, USA. This was taken just as the eruption began in May 1980.

So, all of this means that we had to get the topography of Norfolk Merapi right. If the Firework Volcano is truly going to be a volcano and not just a cone of card with some fireworks coming out we need to find a way to make a proper scale model.

We are starting with the contours, using Geographical Information Systems (and we are lucky enough to have several world-leading experts in that domain at UEA) we will create topographic layers (leaning on the good old contour!) that we will scale up and turn into a frame around which we will build our model.

In much the same way as the fields and trees appear draped over the topography in the photo of Tungurahua above, we will drape the contour frame with (fire retardant) materials and paint it to make it look properly like Merapi.

The relationship between topography, volcanoes and their hazards is an extremely powerful one. In some of the research that we do here at UEA we explored the influence between people’s understanding of the hazard information and the way in which it was conveyed. We found that good visualisations (just like Google Earth) really helped people to situate themselves and rationalise their locations relative to the hazard associated with volcanic flows. Much easier to tell where the truly safe places were. So, absolutely worth all the bother then.

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Two contrasting maps of the island of Montserrat. These show where people questioned located important topographic features when asked to do it on (a) a blank contour map (top) and (b) a good aerial photograph (bottom). Tar River Valley is the main valley where pyroclastic density currents flowed (red triangles). Other features are important hills (orange squares and green triangles) and valleys (blue v’s) relative to volcanic hazards. Maps are adapted from a diagram in Haynes, K., Barclay, J and Pidgeon, N.F. ‘Volcanic hazard communication using maps: an evaluation of their effectiveness’ Bulletin of Volcanology 70:123-138

And, finally, of course, its just amazing to have the opportunity to add just that little bit more topography to Norfolk, even if it is only temporary.

[You can find out more about the work we are doing on risk communication and a host of other research related to living alongside volcanic eruptions by visiting streva.ac.uk or following  @StrevaProject  ]

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