17 August 2011
“Mount Boom” a bit of a bust: NatGeo’s “How to Build a Volcano”
Posted by Jessica Ball
Last week I happened to be watching the National Geographic Channel and caught their new program, “How to Build a Volcano”. Being somewhat interested in volcano-building processes myself, I sat down with a pad of paper and got ready to take notes for a review.
The show started off with an exciting idea: bring together a special effects team and a group of volcanologists and try to replicate volcanic processes on a large (but controllable scale). Thus, building a volcano. The four volcanologists (Mike Manga and Ben Andrews of UC Berkeley, Josef Dufek of Georgia Tech, and Ed Llewellin of Durham University) worked with special effects expert Max MacDonald to create a 10-meter-high volcano in a Canadian quarry (and we all know from Mythbusters that anything involving an abandoned quarry is also going to involve explosions).
The construction methods involved were pretty much what you might expect from a scaled-up version of a paper-mache tabletop volcano, although in this case the group used shipping containers, mesh, burlap, and spray-concrete. But I noticed one interesting thing right off: This volcano wasn’t exactly to scale. And by “not to scale”, I mean “45 degree slopes”. In most volcanoes, slope steepness is limited by the “angle of repose“, or the angle at which things are too unstable to stay put. This angle is rarely greater than 30 degrees. But Mount Boom, as the group called it, had implausibly steep slopes. The volcano admittedly looked pretty cool for a one-day construction job, but if the volcanologists and special effects folks were trying to make the setup as true to nature as possible, they didn’t do a very good job. (After the main edifice was constructed they did extend the slopes a bit with dirt and gravel, but in volcanic processes, that first drop is pretty important, and oversteepening the slopes can give moving material a lot of extra inertia momentum.)
The volcanologists had two goals in the program: to model pyroclastic processes (namely a pyroclastic flow), and to test whether slug flow was possible in a lava-filled conduit. The edifice of Mount Boom was only really necessary for the first, but used for the second as well, since it would look pretty darn cool to film both there. (Another nitpick: it wasn’t clear from the narration or the explanations the volcanologists were giving that they wanted to observe gas slugs in a conduit, and the narrator kept going on about lava flows.)
While the experiments were being set up, the volcanologists trucked off to some real volcanoes to illustrate what they wanted to model. In one case, a group visited Mount St. Helens, and in the other, went to Stromboli. Mount St. Helens was predictably scenic but not particularly active, but Stromboli was supposedly surprising to the group that visited. Instead of the ‘usual’ Strombolian eruptions, the summit craters were extruding lava flows and experiencing more violent Strombolian eruptions. (The show played on this to make it seem like no one knew what they were going to find up there, which – despite the cloudy conditions – I highly doubt was true. Stromboli is one of the best-observed volcanoes in the world, and I would be surprised myself to find that the volcanologists had made the trek to the top without having first looked into the current eruption conditions.) Note: I deserved to be surprised – apparently this actually was the case! See Dr. Ed Llewellyn’s commentary in this post.
The experiments themselves are pretty clever. In the pyroclastic flow reproduction, fly ash, sand and rocks (as well as colored balls for tracers) were heated and then blasted from the volcano with compressed air and explosives. It wasn’t a sustained eruption, but it was enough to produce a column of material that then collapsed and formed a ‘pyroclastic flow’ on the lower slope Mount Boom. The eruption was recorded with a FLIR thermal camera and a video camera, slides were laid out to catch fallout, and posts were placed in the path of the flow and covered in sticky tape to collect samples. In the ‘Strombolian’ eruption, a boiler was set up to ‘erupt’ heated, pressurized water; a gas trap within the boiler was able to release ‘slugs’ of carbon dioxide into a clear column of water, with the goal of seeing if the gas would maintain its coherence through the length of the conduit. The experiment proved that in a cylindrical conduit, it was possible to expel a slug of gas and burst it at the surface, creating the spray of ‘lava’ that characterizes a Strombolian eruption.
The experiments – difficult setup aside – were pretty straightforward and performed well for only a few days’ worth of setup, but there were some problems which could make it difficult to use the results in a publication (if that was ever the goal of the investigation).
Something which could be due to some poor editing (or ignoring the scientists’ input) are the narrator’s comments on the results of the pyroclastic flow experiment, which are extremely misleading. In the show, the narrator says that pyroclastic flows have been thought to be relatively “simple currents” – which is incorrect. Volcanologists have thought for decades that pyroclastic flows are complicated phenomena, encompassing elements of granular and fluid flows. Current pyroclastic flow models (such as TITAN2D and VolcFlow) assume this in order to choose the equations which define the flow behavior. Saying otherwise ignores the research that’s been – and is being – done to work out how different parts of a flow (the rocky basal avalanche, the overlying turbulent cloud of ash and gas, the mixing zone between the two, etc.) interact.
The experiment shown on “How to Build a Volcano” may have produced the first artificial pyroclastic flow of such a large size, but the results aren’t didn’t seem to me to be particularly groundbreaking. I’m curious why the volcanologists depicted in the show didn’t object more strenuously to this inaccurate characterization, but to give them the benefit of the doubt, they probably weren’t involved in the scripting or editing process. On a positive note, using sticky tape and colored balls for markers in the PF was a cool idea, and something that you couldn’t get away with in an actual flow. Instead, scientists have to use rock types, mineralogy, textural, and photo/video evidence to map flow paths. It’s also totally impossible to sample a flow as it’s happening, which the sticky tape allowed the volcanologists to do.
The gas “slugs” simulation is interesting, but didn’t appear to be not very accurate. (Note: There’s a lot more background to this than I realized – and scaling concerns – so again, check out Dr. Llewellyn’s comments here.) An experiment which was trying to approximate the behavior of gas in a magma should have used something much more viscous than water. This would be a bit difficult, especially if you had some sticky substance gunking up the boiler, but as it was presented, this experiment didn’t try very hard for an accurate model. Also, the model raises some questions because it assumed that the “conduit” was a lovely smooth-sided tube, which probably wouldn’t be the case in a natural system. What happens if those gas slugs run into rough walls, or obstructions? The results of the gas slug experiment were visually appealing, but seemed pretty preliminary – not as final as the narrator made them seem.
I suppose it’s too much to expect a TV show to be totally accurate when it comes to scaled-down natural systems, but I was confused at the way the experiment was being portrayed – as if it was rigorous enough to be used for significant research. There are some problems that would have been fairly easy to fix, but as it was presented in the show, the experiment was neat but more of a visual spectacle than anything else. The idea of bringing special effects experts into the mix was something that might be useful to pursue – especially for a setup like Buffalo’s new large-scale volcanological experimental facility. All in all, it was an entertaining show – I certainly wouldn’t pass up the chance to build a giant model volcano – but the science needed appeared to need a little work.
I was thinking the same thing. The description of the show definitely did not match the actual show. I was SO disappointed!
I enjoyed your review and have decided that must be a very tolerant and generous person. Even though I often have the TV as background media I chose not to watch this show because I expected so little. One thing I was wondering about which you might be able to answer is whether there is the possibility of learning something useful from a small scale experimental simulation along these lines? Before I read your review I would have guessed not, but your review implies the belief that there might be something worthwhile to be gained.
Oh, there is definitely lots to learn from small-scale experiments – most of the ones that volcanologists (and geologists in general) perform are necessarily scaled-down from natural phenomena, just because it would be so difficult to experiment on something like a pyroclastic flow or volcanic conduit. As I mentioned in the last paragraph, my own institution is developing a facility dedicated to this kind of experimentation, so there is definitely impetus for it!
I saw the show, too, intrigued at what they might have in mind, but theirs was a collosal waste of time, I thought. Too many differences in materials, pressures, heat, etc., to bear any resemblance to what happens in a real paroxysm.
I wouldn’t say it was a total waste of time – just seeing if they could set up an experiment like that is definitely useful, and something that my own university will eventually be trying to do – but they could certainly have been more rigorous in the material and structural choices. That said, in any experiment or model approximating a natural system, there have to be simplifications, because there are just too many variables to every possibly model accurately.
Going to see if they will be re-airing that.
Your post is so informative.
Very glad I found your blog! All of my art is inspired by nature and geology, and my current series of paintings is inspired by my time at Kilauea Volcano.
I am your newest blog follower and invite you to check out my blog, too.
Best,
Mary C. Nasser
http://www.marycnasser.com/blog.html
[…] featured in National Geographic’s “How to Build a Volcano”, with commentary on my review of the show. He’s given me permission to post excerpts from his message here, which will clarify a few […]
The NG show had a bit of a ‘pimp your volcano’ feel. Lots of welding and big machines.
To see what might have been possible with a more rigorous approach to mount boom-scale experiments, see papers below. Scale of those is a bit smaller (not that much smaller for the operational bits), but much greater than lab scale. And everything else …
Dellino P, Zimanowski B, Buttner R, La Volpe L, Mele D, Sulpizio R (2007) Large-scale experiments on the mechanics of pyroclastic flows: Design, engineering, and first results. Journal of Geophysical Research-Solid Earth 112 (B4): doi:10.1029/2006JB004313
Dellino P, Büttner R, Dioguardi F, Doronzo DM, La Volpe L, Mele D, Sonder I, Sulpizio R, Zimanowski B (2010) Experimental evidence links volcanic particle characteristics to pyroclastic flow hazard. Earth Planet Sci Lett 295 (1-2):314-320
The planned Buffalo facility will be cool when (if?) it gets set up — hope it happens.
[…] nice: magmacumlaude. (Yes, geologists are given to bad plays on words). See for example the write-up of NatGeo’s “How to build a volcano“. LD_AddCustomAttr("AdOpt", "1"); […]
Hi Jessica, my name is Mark and I was the picture editor on the show. A great experience it was, let me just say that. That said, as much as I respect your scientific eye, unfortunately with broadcast television entertainment value is always at the top of the list. You of all people would know, with any science…leaps and bounds are made in tiny little seemingly insignificant steps.
Unlike the science community, the TV audience is fickle, impatient and strangely enough will (research indicates, these aren’t my rules) flip the channel if they’re not following or bored. It would have been great to have made it a 90 minute and we could have expanded the science element more. We shot a ratio of 90:1 so 90 hours of footage for a 1 hour documentary. There is a LOT of science in there, the volcanologists are the real deal and the pyroclastic flow materials (choices) had their scientific purpose.
Anyway not writing to defend per say, just giving you the slightly askew perspective of the TV world. I thought all scientists involved were great guys, VERY smart in their field and will hopefully be able to carry on further and less TV friendly experiments to help further the knowledge of how these geological beasts work.
All the best with your educational ventures!
-Mark
Mark,
Thanks for the insight! I’ve talked to a few of the scientists since, and I have a better appreciation for how they were constrained by the setting and the filming arrangements – and what had to be done to make the experiment television-worthy. It is too bad it couldn’t have been longer, but for a broadcast show there was definitely a lot of science packed in (and science that most people don’t get to see!)
We’ve recently had some folks filming our large-scale experiments at UB, and I can see how difficult it must be for filmmakers to tell a compelling story while compressing a multi-day experimental setup into an hour or so! It’s great to get some perspective on it from the media side of things, though.
Jessica
Our job isn’t that difficult, we do what we love and I hope the same for you! It seems like it!!
All the best with your studies Jessica! I’ll look for you as a scientific contributor in future series!