The artistry of geology

CHRIS HATZIS
Eavesdrop on Experts, a podcast about stories of inspiration and insights. It’s where expert types obsess, confess and profess. I’m Chris Hatzis, let’s eavesdrop on experts changing the world - one lecture, one experiment, one interview at a time.

You’d be surprised at the vast history lying just beneath our feet – from remnants of channels carved deep below, to evidence of glaciers long gone, and hundreds of fossils waiting to be excavated. The known layers of rock underneath Melbourne date back some 400 million years – but that is just the beginning.

Michael Webster is an engineering geologist at Golder Associates who also lectures for the Master of Engineering here at the University of Melbourne. He’s passionate about Victoria’s geological history and its continuously evolving state.

Michael and Golder Associates recently undertook geotechnical assessments of the Testing Grounds site at the arts precinct of Melbourne for future development. Golder’s experts developed 3D models of the geology of the site and the main model was 3D-printed and featured in the exhibition 'Turning Digital Geology into Art: an underground journey into Melbourne’s arts precinct'. Art and science successfully mixed.

Our reporter Dr Andi Horvath sat down to talk all things rock and soil with Michael Webster.

ANDI HORVATH
Now, you lecture here on campus in geology?

MICHAEL WEBSTER
Yes I do. I actually just came from one just now. I lectured the Master of Engineering students on the engineering geology of Melbourne and on-site investigations. The lectures are ongoing so I’m not going to give them any answers to the assignments for the end of the week.

ANDI HORVATH
Oh okay. If we were stalking you today, what revelation would we hear about Melbourne and its geology?



MICHAEL WEBSTER

People don’t actually know all there is to know about it. So there is - as Donald Rumsfeld would say - lots of known unknowns and unknown unknowns in it. There is some rock that’s 400 plus million years old, 380 million years and then there’s nothing for the next 340 million years. So there’s a big gap where we don’t actually know anything. There’s nothing recorded. There’s no evidence of dinosaurs in Melbourne at all. So you have to go down a fair way down to Gippsland or out Bacchus Marsh way. But yeah there’s a huge gap in our geological history we don’t know about.

ANDI HORVATH
Is that because the layers are just not there, telling us what happened during that era?

MICHAEL WEBSTER
Yeah, that’s a pretty good way to look at it. So either they were never deposited in the first place, which is kind of unlikely over such a time period, or they were deposited and then scrubbed away. Out in Bacchus Marsh for example, during a period called the Permian, there’s actually evidence of glaciers, alright. So there’s evidence of glaciers just outside of Melbourne, nothing recorded in that era at all around Melbourne.

ANDI HORVATH
Some people might even say, don’t we know everything about what’s under the ground and let’s just leave it there and if there’s nothing important what’s there to do?

MICHAEL WEBSTER

Why do we care? Yeah, totally. So the answer is we know a little bit. We’ve seen a window into it but, for example, the deepest we’ve drilled I think off the top of my head is about 14 kilometres and that was done a long time ago. The radius of the earth is about 6300 kilometres so already if you look at that as a percentage, we haven’t really gone very far. But more than that everything that you do interacts with the ground really if you think about it. Even an aircraft has to land somewhere on a runway and the runway has to be built to a certain standard on the ground. Your tunnels, your buildings. Everything interacts with the ground even if you don’t think about it and because of that you need to understand a lot about what’s going on. Because geology varies it’s a natural process, it’s never the same. You can have completely different geology at sites that are next to each other.

ANDI HORVATH
Do you have a research topic at the moment you’re investigating?

MICHAEL WEBSTER
One of the big things that I’m particularly interested in is the neotectonics of Melbourne. You might not know it but we have very little earthquakes - even in central Melbourne - quite frequently. So everyone knows about - well a lot of people know about the earthquakes down in Gippsland or the Otways but actually in Melbourne itself there have been earthquakes.

ANDI HORVATH
Have there?

MICHAEL WEBSTER
There have. Very, very little ones.

ANDI HORVATH
I’ve not felt a thing.



MICHAEL WEBSTER
Oh that’s the thing, you’d have to be a seismic instrument to actually feel these ones but they are there. They occur at all depths, some of them quite deep, some of them quite shallow. I was actually in conversation with one of your colleagues from the Geology Department about them and about the location of them and where these fault structures go. It’s been fantastic.

ANDI HORVATH
Well do tell. Why are they there?

MICHAEL WEBSTER
Well, they exist because of things that happened hundreds of millions of years ago. These faults in the ground are formed by huge pressures. Think about places like the western United States, they’ve got the big Cascade Range volcanos over there and we had something similar hundreds of millions of years ago where we are today. The forces and the stresses broke the ground in these fault zones and these fault zones - obviously the ground didn’t heal itself - they’re still there. So the forces today, even though they are different, still exploit those weaknesses that exist in the ground and so stress regimes change, things change but those defects are still there and you still get those earthquakes even today. That actually goes so far as not just earthquakes but the ground is lifting in different places in different ways and it’s sinking in other areas. You can sometimes draw pretty straight lines to actually see these things. It’s quite remarkable.

ANDI HORVATH
How do they actually measure that? I’ve got in my mind these ancient Chinese frogs that hold a ball in their mouth [laughs].



MICHAEL WEBSTER

[Laughs].

ANDI HORVATH
If there’s an earthquake they drop the ball and that’s how we know things are happening. I think things have moved on since then.

MICHAEL WEBSTER
Just a little bit.

ANDI HORVATH
How do they [laughs] measure earthquakes?

MICHAEL WEBSTER

So they use seismographs. Very, very sensitive equipment. It’s typically buried in the ground a little way so that you don’t have any atmospheric influence and they measure very minor earth tremors. But these things of course, if you’ve got heavy trucks driving by or you’ve got a variety of things, all of that will interfere with this equipment. But yeah, things buried in the ground all over the place and you can - if you have three of them and they work out when the wave hits at each location, you can actually triangulate exactly where the earthquake occurred in three dimensions.

More than that now we’ve even used things called interferometry where you have different wavelength stuff coming in from satellites down to the ground and all the way back up to space and they can measure minute changes across a large area to work out if things are moving, both horizontally but also vertically. So you can see in incredible detail, for example London and the way it’s broken up into a whole lot of different fault blocks. You don’t think London is a place of earthquakes and active tectonics but it is. It’s moving all the time.

ANDI HORVATH
In cases of large earthquakes, particularly the devastation that some of them can cause, are we better at predicting earthquakes?



MICHAEL WEBSTER

Unfortunately, not really. We know generally where the really nasty zones are. So for example Alaska, the western United States, Japan, the Philippines, Indonesia, effectively the Pacific Rim of Fire is a great example. But there’s an amazing study called the Lisbon Earthquake. It was in 1700 and something, it’s described as the earthquake that killed God because it occurred on - I believe it was on All Souls day - sorry, All Saints day or Christmas, one of the two - and everyone was in church, the earthquake struck - it was a magnitude nine estimated which is an enormous earthquake, it’s about the same one that hit Japan - flattened the churches, flattened the city. The city caught on fire, everyone ran to the harbour then a tsunami hit and killed all those people that ran down to the harbour.

So it was a devastating earthquake and the crazy thing is they still don’t know why it occurred. Because it’s nowhere near anything geologically that’s telling you, watch out there’s an active fault and there’s something going on. So they don’t know why. Yes you can predict sometimes as to where it could be, you don’t know when it’s going to happen generally - you get a bit of a feel maybe but there are always these random events that are just - yeah. It’s crazy but it’s true.

ANDI HORVATH
Okay so there’s still some work to be done.



MICHAEL WEBSTER
[Laughs] just a few things to be done yes.

ANDI HORVATH
[Laughs] okay.



MICHAEL WEBSTER

[Laughs].

ANDI HORVATH
Well your students better get onto it.

MICHAEL WEBSTER

I know. Neotectonics, it’s a great topic.

ANDI HORVATH
[Laughs] tell me about your artwork endeavours. You’ve somehow combined geology and artwork.



MICHAEL WEBSTER
[Laughs] yes, trust the art gallery to manage to find an exhibition out of anything. But yeah, so basically what I do as a day-to-day is build three dimensional ground models, alright. So effectively I’m trying to recreate in three dimensions what’s happening in the ground. Of course because there’s a lot of history there, things crosscutting each other, geological surfaces, lava flows - there’s two lava flows inside this model and a bunch of other things, effectively get these beautiful layers cutting across each other, building up and up and up over, in this case, a series of about three/four million years all built up to the present day. As a result of that you get this really quite beautiful, intricate, three dimensional picture which we presented to the Arts Centre more as a, for your interest and information. The Arts Centre then said to us, we want to exhibit that. Can you print out some posters and such and we said, sure. Then they said, we want to 3D print that, are you okay with that? Sure.

So we’ve 3D printed the ground model in collaboration with the Arts Centre and Development Victoria and we put on an exhibition at the Testing Grounds which is on City Road and Sturt Street there. It ran for a few weeks and it was lovely to see people’s interest and connection with the ground. I’ve always found that geology is - it’s one of the more approachable sciences. If people talk about gravity waves it’s absolutely fascinating but I mean I’ve got no idea what I’m hearing or seeing. Whereas with geology it’s there, it’s rivers, it’s volcanos, it’s lava. It’s all those things.

ANDI HORVATH
It’s tangible.



MICHAEL WEBSTER

It is, it’s entirely tangible.

ANDI HORVATH
It’s visual. Yeah.



MICHAEL WEBSTER

That’s right. It operates at a time scale that I myself really struggle with and most people don’t appreciate, but it’s there. You can touch it. You can see it. Exactly.

ANDI HORVATH
Now when you look at the layers of what’s underneath us, you would have assigned colours to these. Because I was thinking, how can that be an artwork? I mean isn’t it all shades of brown and yellow and [laughs].



MICHAEL WEBSTER

[Laughs].

ANDI HORVATH
But, how does it work? Why does it become art?



MICHAEL WEBSTER

It’s funny isn’t it because, yeah you think it’s all shades of brown and grey and green and generally it actually is in the ground. Now you’re talking to a man who’s colour blind so I have been prescribed the exact red/green/blue values that the geological survey of Victoria gave back in the day for the different geological units. However, originally the first geological maps produced over in the United Kingdom were produced in such a way that the geologists at the time used the colour of each of the soils or rocks that he encountered and actually used that to create the geological map. So their geological maps are very much those muted colours but they are beautiful because you can actually see what’s in a reality. So if you were to go out into central Australia for example and you had that beautiful, rich, red colour, that’s exactly what you would see on the geological maps should you have followed their way of doing things. It’s remarkable. It’s beautiful.

ANDI HORVATH
I guess it’s not every day we hear the word geology and art in the same sentence.


MICHAEL WEBSTER

[Laughs] no.

ANDI HORVATH
It’s a genuine collaboration. Where to next with this project?

MICHAEL WEBSTER

Universities, actually. So we’ve talked to a number of universities just quietly about such things. Three dimensional modelling is something that’s not going away professionally and in fact now some contracting companies and government bodies will refuse to deal with you if you are not producing things in three dimensions, for a number of reasons. So we’ve been promoting that for universities and as part of that, what better way to promote it than to say, well it’s art, it’s here, it’s very pretty and you can get exhibited.

ANDI HORVATH
Michael, tell me about your career and some of the changes you’ve seen in geology or geology research.



MICHAEL WEBSTER
The great thing about it is from when I started to now we have learned a lot. We talked about is there - if you know everything there is to know. The answer is no. We - even within Melbourne we’ve discovered new geological units. I mean for example the eastern half of Melbourne according to the geological map is all that old bedrock material. But we found these deep, 18 metre deep channels carved through the city that aren’t noted. It’s been wonderful to actually map these things out and share that knowledge.

The other big change that I can see is the shift from two dimensions to three dimensions. So that shift occurs because obviously now computers are getting more powerful but people are asking a lot more of the information that you put forward.

So, originally you get out your coloured pencils, you draw on your borehole sticks and you connect the lines in a way that made geological sense. Now you get all of this information, you interrogate it, you draw it into three dimensions and you create these beautiful geological surfaces that are then incorporated into the geotechnical design and you can actually influence design in a significant way with this three dimensional modelling, such that they can shift the alignment of a tunnel or change where a railway station is put and these kind of things. It’s all very collaborative.

ANDI HORVATH
What are some of the misconceptions people have about geology?



MICHAEL WEBSTER
You actually touched upon it before when you said that everything was known. So what you find is that people assume that the geological map of Melbourne is the answer and the memoirs that are written about the geological map are the answer and then you’re effectively just plodding along site by site with already effectively the cheat sheet in front of you. The answer is no. It changes so rapidly that everything you see is just a generalisation of what’s there and even the generalisation isn’t necessarily accurate. For example, the geological map was drawn in 1973 and it’s built upon earlier works but ultimately there was already a city on the geological map when the time came, so how could you possibly give an accurate representation of what’s in the ground. People tend not to think about that and they just assume that, yeah what you see is what you get, what has been done before is the answer. This doesn’t even touch upon the fact that sometimes people actually came to the wrong conclusions.

So some of the geological units that were described previously were actually completely separate beasties from each other and they were just lumped together but there’s actually millions of years between them. They come from completely different origins. For example what was thought to be river iron sediments actually were something called a tuff. It was an explosive volcanic event. Yet they were lumped in together with each other. Things like that.

ANDI HORVATH
One burning question I’ve been dying to ask a geologist and I’m in the position to be able to do that now [laughs] right here.



MICHAEL WEBSTER

[Laughs].

ANDI HORVATH
Is do we still find new rocks? You know how biologists find new species or they might find a species they thought was extinct and it’s come back. Do geologists still find new types of rocks?



MICHAEL WEBSTER
In a way yeah. So there are certain minerals and things like that that are unique to particular areas. So there’s this old fella out in Broken Hill and he’s got his museum of minerals that he’s found over the last however many dozens of years of working out there and some of them are unique to his shed basically. He’s found them out there and that’s it. They haven’t been found anywhere else. Much in the same way now if you’re actually talking about rock types and these kind of things, well yes but you’re going to have to go to other planets, which is what they’re doing, alright. So they’re looking now in other areas and other places for interesting and different geology. In fact if you want to be an astronaut, one of the best careers [laughs] to have is that of a geologist. You’d be surprised at how many geologists have made it into space.

ANDI HORVATH
[Laughs] so your students will probably find jobs. Michael what advice do you give to your students?



MICHAEL WEBSTER
Everything that’s come before you is an approximation and there is no one answer, alright. So the advice that I was given to do with this ground modelling is every ground model is wrong just some of them are useful. Much in the same way there is no one answer. If you ask 10 geologists to draw you up the ground model with the same data you’ll get 10 completely different models. However, it’s the way that you interpret the information to make geological sense and being able to communicate that with others which differentiates you from anyone else.

ANDI HORVATH
One of the big issues in society is about the sustainable soils of the future and that soils are disappearing. Are geologists contributing to this sort of future of soils as well?



MICHAEL WEBSTER
Not as much as you’d want them to. Geology and engineering in general is quite a conservative profession and look I get that. For example, concrete technology. There’s technology out there now that is a far more environmentally friendly version of what’s happening in the industry currently. However, if you’re relying on this concrete to hold up a 70/80 story building, you don’t want to be on the experimental edge, you know, if something goes wrong. However, I think that they can do more. So one of the areas that I studied in my undergraduate, which I am disappointed to see not being adopted in Australia - however it is adopted overseas - is something called shallow geothermal energy. Shallow geothermal energy involves effectively storing and retrieving heat out of the ground. So in summer you put heat into the ground - cool your building - and in winter you pull that heat back out again and heat your building. It’s a far more efficient way of heating and cooling your building than what we use now. It’s effectively like a delayed solar power in a way.

ANDI HORVATH
I love that.



MICHAEL WEBSTER
So do I. Come on everyone, [do] it.

ANDI HORVATH
Yeah. Alright. PhD students.



MICHAEL WEBSTER
Yeah, that’s right. Well in fact Melbourne University PhD graduands in the field of shallow geothermal energy are now associates and principals at Golder where I work. We try and push this technology but we find the industries to be a little bit on the conservative side. I’d encourage universities in particular to try and adopt this technology and prove that it works in Australian conditions. Then be a leader to industry to show that this is actually the way of the future.

ANDI HORVATH
Needs a little dollop of entrepreneurial spirit and start up energy I reckon.

MICHAEL WEBSTER
That’s right.

ANDI HORVATH
Come on, come on millennials, off you go.



MICHAEL WEBSTER

[Laughs].

ANDI HORVATH
You’re the key. Michael, we love our experts to obsess, confess and profess. I need a confession from you.

MICHAEL WEBSTER
You don’t always get it right. I’m an engineering geologist so part of my work is engineering and sometimes the geology surprises myself and it surprises others and you don’t always get it right. So things fall down for example and you’ve just got to be mindful that your designs and your communication with others is such that you can actually accommodate that safely. That things aren’t always as you expect them, as you model, as you predict.

ANDI HORVATH
Next time we see some cutaway earth or next time we see an interesting rock sample, what do you want us to think about?

MICHAEL WEBSTER
Think about its history. So for example, if you’re driving along in Gippsland and you go to the side of the road down there you might be able to find little fossils in the rock. These things existed before trees were on the earth. These little fellas were in a shallow sea environment and they were - they lived their little lives out there, but they lived in a time period that is so completely different that if you were to stand on the Australian continent - for a start the eastern third would be missing - and the rest of it wouldn’t have any vegetation at all. All the life at that time existed in the oceans. Just an appreciation that not everything you see today existed previously and things always change and it changes in such an imperceptible and slow way that we can’t really appreciate it.

ANDI HORVATH
So even the map of deep time, which is what’s below the surface, is an ever evolving thing?

MICHAEL WEBSTER
Absolutely, yes. Geologists enjoy fighting amongst themselves as to what constitutes different geological eras and yes our understanding is constantly evolving. Absolutely.

ANDI HORVATH
Michael Webster, thank you.



MICHAEL WEBSTER

Thank you very much for having me.

CHRIS HATZIS
Thank you to Michael Webster, engineering geologist and lecturer at the Master of Engineering, University of Melbourne. And thanks to our reporter Dr Andi Horvath.

Eavesdrop on Experts - stories of inspiration and insights - was made possible by the University of Melbourne. This episode was recorded on September 17, 2019. You’ll find a full transcript on the Pursuit website. Audio engineering by me, Chris Hatzis. Co-production - Silvi Vann-Wall and Dr Andi Horvath. Eavesdrop on Experts is licensed under Creative Commons, Copyright 2019, The University of Melbourne. If you enjoyed this episode, review us on Apple Podcasts and check out the rest of the Eavesdrop episodes in our archive. I’m Chris Hatzis, producer and editor. Join us again next time for another Eavesdrop on Experts.