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Douglas Schmitt

Douglas Schmitt

Professor and Stephen and Karen Brand Endowed Chair of Unconventional Energy, Purdue University

By David Zierler, Director of the Caltech Heritage Project
May 3, 2022

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It's Tuesday, May 3, 2022. I am delighted to be here with Professor Douglas R. Schmitt. Doug, great to be with you. Thank you for joining me today.


ZIERLER: To start, would you tell me your title and institutional affiliation?

SCHMITT: Right now, I'm the Brand Professor of Unconventional Energy at Purdue University. But I've actually been here only since 2018. Before that, I was at University of Alberta as a Professor and Canada Research Chair for 29 years.

ZIERLER: Who are Stephen and Karen Brand? And is there any particular connection with your research?

SCHMITT: He was a PhD geology graduate from Purdue, and he went into the petroleum industry and did quite well. He's there in Houston, and I met them. He's a geologist. He just wanted there to be more geology/geophysics input to a lot of the modern things going on with energy developments. A lot of it is engineering driven. I think that was his prime motivation, that really, there should be geology/geophysics-type people more involved, too.

ZIERLER: I can't help but ask, but the term unconventional in your title, unconventional energy, what does that connote as it relates to what you do?

SCHMITT: I connote it to mean different things. Some people would make that mean hydraulic fracturing in shales for gas production. But I've been involved with understanding rock properties with that, and forces in the earth, and induced seismicity, for example. But I'm also very interested in other aspects, say, related to sequestration of carbon, and coming is sequestration of hydrogen because we need to store hydrogen if we move a lot of our processes that way, underground and also geothermal. I've been involved with all of those kinds of aspects.

ZIERLER: There's geophysics, there's seismology, there's mineral physics, earth material physics, so many difficult subfields. At the end of the day, what's the best way to describe what you do?

SCHMITT: I'm a little bit of an odd duck, so I would describe myself as a rock physicist, but I do both lab and field work. Because the earth is what we're measuring, trying to understand the physical properties of the earth. But at the core of what I do–and it comes here in my time at Caltech, actually, I was a mineral physicist. I've grown away from that, but it's really understanding rock properties in the earth and how they're affected by different things, whether I'm doing it in the field or in my lab.

ZIERLER: Is your research more on the observational-experimental side or the theoretical side?

SCHMITT: You have to be a special person to be a theoretician, and I'm not patient enough. I'm really more an observational type of person.

ZIERLER: Are there theories that provide guideposts to your observational and experimental work?

SCHMITT: Of course, and part of my work has been trying to test some of those theories, which need to be tested, in my view. For example, how seismic waves reflect off of different kinds of interfaces in the earth. In my lab, we developed ways to fundamentally test some of those theories that have been around for a long time. But nobody ever tested them. And we took a lot on faith. Things like that. But running the gamut through to studying–take this piece of rock. How would it behave under the pressure and temperature if I stick CO2 into it? What would its seismic waves be? There's quite a gamut within my lab.

ZIERLER: For you, when is it important to do field work, to go out yourself, and when is it sufficient to have data remotely coming to you?

SCHMITT: I guess I'd never really had data remotely coming to me. Part of my PhD work at Caltech was on measuring forces in the earth from bore holes. It was kind of a bizarre project. But that got me into scientific drilling in a big way. And I've been involved with probably 15 or more scientific drilling projects globally on a variety of different topics. We go out, we're on the rig, we collect the data, we also collect active source where we have our own vibrator truck, and we'll collect seismic data over certain kinds of features in the earth. Right now, we're doing a lot with impact structures, for example, trying to understand their structure, the velocities within them, what that means for damage, how craters are created, issues like that. Very rarely do I get data from someone else. Usually, I'm the guy who likes to go out and get it. Maybe I'm crazy. [Laugh] But that's not the way a lot of the science is done today, I realize.

ZIERLER: What interface do you have with industry, either for utilizing some of their tools or, on the flip side, them taking an interest in what you're doing and applying it for commercial purpose?

SCHMITT: Of course, I use similar tools to what industry would use, particularly seismic reflection profiling. But what's in my lab is actually quite unique. In the past, companies or projects that were industrially related would say, "Send me earth materials." And we'd try and characterize them as much as we could, basically abuse them in the lab, subject them to pressure, temperature, pulse them, measure how much they squeeze up, things like that. And that has applications to understanding–at scales that I can't deal with, say what they deal with in industry, very, very large scales, orders of magnitude, what kind of data they can collect. It's almost impossible for a professor to deal with that today. But that allows them to then interpret their data more fully. For example, if you're injecting carbon dioxide into the ground, and you want to know where it goes. The work that we've done in the past would help you interpret those seismic results to say, "OK, it's here, and maybe the pressure is that, and there's so much CO2 there," things like that. That would be one example.

ZIERLER: With all of the talk about sustainability in the field–you mentioned carbon sequestration. Does that affect the kind of research you do and are able to do? Or is that really just a buzzword?

SCHMITT: No, it's something that's going to be happening probably on an increasingly large-scale. It's stop-gap. We can't cut the fossil fuels overnight, and we're never going to be completely able to do that. There are certain things we still will need. But we can't release so much CO2 either, or greenhouse gases in general. The stopgap for the next few decades will probably be just putting it underground. It's going to require a huge amount of effort and resources, and it's going to provide maybe 15% of the solution. But it's happening and is going to be happening at an increasing scale just because of the pressure to reduce CO2, particularly for industry. Coal-fired power plants don't make money anymore, but things like that that are producing a lot of CO2, making cement, making steel.

We need to do something with that. For the time being, getting rid of the CO2 is probably going to be a fairly important part of reducing the amount of CO2 that actually gets released. And it's actually pretty interesting scientifically. You take something that's somewhat chemically reactive, has unique physical properties itself, and you put it into the ground, and what happens? It runs the gamut from producing earthquakes to how does it react underground 100 years or 1,000 years become rock itself? There's a wide variety of really interesting issues with that. If we go to hydrogen, I think that's even going to be more intensified because hydrogen's more reactive and biologically active in things. Both those two things will be ramping up in this decade, I think.

ZIERLER: I'm curious what of the seismic monitoring techniques you learned at Caltech have stayed with you throughout your career.

SCHMITT: Actually, I didn't do seismic. I worked with Tom Ahrens. You probably talked to other people who worked with Tom Ahrens. He had these cannons, and we fired things at minerals, put them under very high pressure and temperature. That was half my thesis. The other half was working on trying to measure forces and stress in the earth. That's kind of the launching pad that sent me down into rock properties and drilling. I took courses on seismology at Caltech, but a lot of what I'd done in the applied seismology–I did work before I came to Caltech in industry as a geophysicist, so I had some background that way. Then, I developed a lot of what I've learned since when I was an assistant professor and continuing. I think what Caltech did give me was a good theoretical background to have that and some of those skills. Although, like I said, I'm not the best theoretician. [Laugh] But just a good grounding to move from.

ZIERLER: What about optical interferometry? Was that something you did at Caltech?

SCHMITT: Yeah, it was. That was the stress measurement. It was kind of a bizarre project. I guess I'm old now, but you've probably seen the holograms with laser light in three dimensions. We applied that technique to measure tiny deformations on a bore hall wall, and those tiny deformations would tell us what the force in the earth was. When we got that, we could understand the stresses in the earth. I was really involved with that, and I continued that. I actually developed some other techniques that continued–it was more in the engineering literature–trying to measure tiny deformations of thing using optical methods, and those techniques still exist today. But that was the project that kind of got me down the road that I'm on now, into my post-doc and from there on.

ZIERLER: For your research group at Purdue, what are the kinds of careers that your students go into?

SCHMITT: Well, let me back up because I've had a lot of students. [Laugh] I've had about 20 PhDs and maybe 45 masters. Alberta was a good place to be because we had a very strong, very quantitative geophysics group. Most of the people went to industry. I should have 300 papers, but they start working before they're finished, most of them. And some went into academia, of course, globally. One of them just became the chief geophysicist of Saudi Aramco, for example. They've all done very well. At Purdue, I'm rebuilding the group. It's like starting again, coming to a new country. I have three grad students. I think one will probably go to industry, one for sure should be a professor, but she wants to go to Google. [Laugh] It pays so much right now. She's a very brilliant woman. The master's student I'm hoping stays as a PhD, and he wants to do planetary, so I'm sure he'll be academic. But here, it'd be more academic at Purdue than it would've been at Alberta. I've had students doing quite a mix of things and in different industries, too. As you probably know, earth sciences have had a bit of a problem the last five years or so, at least in industry. But the good thing is that my students were able to find jobs in machine learning and take it elsewhere. I'm happy I gave them the right background that they could do those kinds of alternative things.

ZIERLER: Just as a snapshot in time, what are you currently working on?

SCHMITT: I'm not good at saying no. [Laugh] Right now, one student is working on a deep bore hole in Alberta, the analysis of the stresses and the forces in the earth there. Another student is working on bore-hole data I collected with my colleagues on the Alpine Fault in New Zealand to understand it and its structure. There's a meteor impact crater very conveniently nearby, 30 miles away, and we collected seismic data over that. One student is working on that for his master's. Recently, I had two PhDs finish. One did his work on seismic work and rock properties associated with the Chicxulub impact that killed the dinosaurs and was on that drilling project. The other one was working on forces in the earth related to induced earthquakes, where we were able to understand the forces in the earth better and try and determine what caused those earthquakes. I do too many different kinds of things, I think. [Laugh]

ZIERLER: Let's now go back prior to your time at Caltech. Tell me about your education at the University of Lethbridge. Were you specifically focused on geophysics and seismology, even then?

SCHMITT: No. It was a great time to be at the University of Lethbridge. It was only 1,500 students. It was a brand-new university almost, maybe less than a decade old. I was TA-ing my third year, and I got to know the professors very well. There was no geophysics then. It was too small a school. But there was physics, so I took a physics degree. That got me a good background in physics, and I wanted to continue in physics. Then, what happened was, literally, I was walking down the hall before I graduated, and my former TA said, "Hey, Doug, you want a job?" And I said, "OK." [Laugh] Because I hadn't really planned out what I'd be doing as well as I should've. I got an interview, and I got a job as a geophysicist in 1980. If you recall, that was the time when the energy crises were high. There were shortages coming off of Iran and things like that, so things were booming. That got me into geophysics, then I went to grad school and kind of shifted to the mineral physics and bore hole stuff with Dr. Ahrens, then moved from there. But I'm glad because I love geophysics. I probably would've been doing some kind of collider physics or something. You never know. But I'm happy I ended up in geophysics because you can bring in so many different aspects. It's really good, broad science.

ZIERLER: Tell me about your time in industry and if that was useful in focusing your interest once you got to Caltech.

SCHMITT: Yeah, it was. That's what got me into geophysics. That's why I applied to geophysics for graduate school. It was at a company called Texaco, which is mostly gone now. But I worked in a geophysics group interpreting seismic data. I didn't have a good idea what I was doing at the beginning, but I learned. It was a different time because there were no computers. Everything had maps, and they colored on the maps, and things like that. But that got me into geophysics, and I was able to play on the computers there a little bit and start my learning. It was a great place to learn, a very supportive environment where you had the senior geophysicists helping the younger geophysicists. And they were very good to me. When I said I wanted to go to grad school, they actually helped support me a little bit. And then, we parted ways very amicably when I said I wanted to do a PhD. It was different times. I don't think things like that would happen today.

ZIERLER: Being in industry and out of school for a few years, what mentors, if any, did you rely on in terms of thinking about where you should apply for grad school?

SCHMITT: I don't know. [Laugh] I was taking some courses at the University of Calgary, and there was a young professor there. But I have to admit, I was pretty naive, so I applied to a lot of different places. I'm not sure why I applied to Caltech. To be frank, it was probably because my aunt lived in the Valley, to some degree. [Laugh] And I wanted to get away and get a broader view. I applied to Canadian schools and some US schools. It might've been why I came to Caltech was I had my aunt close by. [Laugh] But it was a good choice. I have to admit, I was from a small community in Southern Alberta, and I didn't know anything about the academic game at all. I'm still pretty naive. Some people seem to know about this academic game. They're born into it. But I wasn't.

ZIERLER: It seems like you did OK. [Laugh]

SCHMITT: Seems like I kind of fell through. [Laugh]

ZIERLER: What were your impressions when you first arrived in Pasadena?

SCHMITT: I was scared. I'll tell you a funny story. I get to Caltech, and this was the first few months I'm there. And there's this very distinguished-looking fellow walking around with white hair and short, looking official. Then, I thought, "Oh, all these famous professors here, this must be some famous professor." Then, a few months later, I see him, and he's down digging in the flower bed. It turned out to be one of the gardeners. [Laugh] It's a great story, probably a fantastic person, but how he bore himself and everything, I just thought he was a professor. But it was overwhelming. Like I said, times have changed a lot in the world. I came from a fairly isolated, rural area. I was thrown in with my friends now, and they were from all over, like Luciana from Mexico, Ronan from France, and so on, this different mix of American accents. It was a little bit overwhelming at first.

ZIERLER: What was the process for determining who would be your thesis advisor?

SCHMITT: It's not as strong as it was when we were there, and I don't know what they do now, but at that time, you'd come in, and basically there'd be a cohort of graduate students, say, in geophysics. And we'd be put in one room to begin with because they were short of space. But you then started taking courses. Nobody really assigned you a professor. I think today, it's much more–maybe not at Caltech, but other places, you almost know who you're going to work with before you arrive because funding has to be in place and all that. But there, this was one of the beauties of the place. We had to do three projects. Each of them had to be a different topic. And then, after one year, we would present those, and that would basically be our examination as to whether we should continue to be in the PhD.

But during the process of those three projects, you worked with three different professors and got to see a potential project you might like and continue with it. I actually did two with Ahrens because Ahrens seemed to grab onto me for some reason. [Laugh] And another one with Rob Clayton I wish I'd continued on because other people did similar things about a decade later and got it published all over the place. But I did that. These projects were a way to see what you wanted to work on and who you wanted to work with. Then, I ended up working with Ahrens. I think the experimental aspects interested me, and he was also quite an insistent person. [Laugh] I didn't go there saying I wanted to do this with that person. Again, it was back to my naivete of not knowing what I was doing.

ZIERLER: Once you got the lay of the land, what was your sense in the early 1980s that the big debates were in geophysics and seismology? What was happening at the Seismo Lab that people were excited about at that point?

SCHMITT: The mineral physics community, for example, was quite small at that point, just from that perspective. And some of the things that were happening around that time were finding new high-pressure mineral phases, particularly one called perovskite, not at Caltech but at other places, people had found. The growth in trying to understand what might be deep in the earth was one big thing. There were a lot of shorter-term things. There'd be an earthquake, and everyone would run out and study that earthquake for a while. Then, some of the early tomography work of the earth, where people would take the arrival times and back-calculate for what the deep structure of the earth would be in detail, starting to see major structure in the mantle related to subduction and upwelling parts of the mantle. And of course, those have been refined continuously since, those kinds of models. I think those were probably the things that stuck out to me the most.

ZIERLER: What was Ahrens specifically working on at that point?

SCHMITT: He had a large group. He was working on quite a few things. One aspect was trying to measure the temperature-volume-pressure relationships of different kinds of minerals so we could understand better what seismic velocities might be in the earth. There was a lot of that kind of work going on. But he was advancing things on measuring temperatures, for example. Some of the work I did was measuring the temperature of shocked quartz, which would be pressures that weren't that deep, maybe 300 kilometers, compared to what some of the other work is. Another big project was measuring the temperature of molten iron, for example, that Sally Ridden, one of my fellow students in the Lab, worked on. And those are numbers that help constrain–these are still things that are not that well-known–what the outer, molten part of the core might be. Kind of important experiments that way. He was also involved in looking at impact structures related to Chicxulub. He and one of his colleagues did some of the first numerical models of impact structures to see what happens when something big comes in, what gets thrown out into the atmosphere, how shockwaves propagate away, and that was early numerical modeling, which has become quite a subfield now. And then, there was this stress project that I worked on. That probably wasn't as mainstream, but I think he had an idea and got the money to pursue it.

ZIERLER: What computers were in use at the Seismo Lab at that point?

SCHMITT: I can't remember the names, but they'd be nothing compared to what we have today. There was an old-style mainframe that was still there, where you had tapes and everything. You had to learn how to mount the tapes. Then, I think Rob Clayton got a new computer. Unix-based systems were coming in, so I had to learn Unix and C++ with Rob. Then, some of the first kinds of workstations. I remember maybe about two or three years when I was a grad student, Rob Clayton or someone else would've gotten a workstation, and it had a color screen. [Laugh] And you could make images on it. A good friend spent six months just trying to figure out color maps because no one knew this. Things we take for granted today. How to make a color map so if you have an image of something, what that would look like on that workstation. Color screens, actually. Then, Cheryl [?] and I were actually house parents at Page House, so we had access that what I call luggable, 40-pound computers with a little screen like that. Both Cheryl and I wrote our PhDs on one of these things, an IBM kind of thing. Then, we printed it on the main computer at the Lab. That was coming in, the little Apples and those kinds of PC computers. That was starting to ramp up much more rapidly toward the end of my grad school.

ZIERLER: In developing your thesis, how much of it was Ahrens giving you a problem to work on, and how much was you coming up with the idea yourself?

SCHMITT: Well, he came up with the stress measurement, the main idea, and another PhD student had worked on it, then I continued it. And then, the shock wave things, he got me going. But what Ahrens let me do, essentially, and I'm not sure I do this with my grad students, though I should, he seemed to just let me go and develop the experiments after that. Maybe he didn't want to spend the time. [Laugh] But he gave me an enormous amount of freedom. He got me started on shock temperature measurements. That was the first year and a half or so, and we got a little paper. Then, I kind of drove what I wanted to measure, and developed the technique further, and what materials I wanted to study, and how to study them. Of course, there was always supervision, and you could ask questions. But really, he gave me an enormous amount of freedom to do what I wanted.

ZIERLER: What were some of the ideas in the field at that point, and how was your thesis research responsive to them?

SCHMITT: Again, the mineral physics aspect. At that point, I think we were getting a better feel for what was in the deep earth. New techniques were also developing that I was never involved with, but diamond cells, where you could take small pieces to very high pressure and understand the physical properties of the material squeezed between two diamonds. I think it was just at that point that the community was still grasping for answers such as, what are the physical properties of these minerals that might be deeper in the earth? When do they melt? What might be the speed of seismic waves through them? Although, those were indirect measurements. Then, on the stress measurement, it was actually pretty active at that point. There were a lot of people working in bore holes, trying to understand earthquakes and how they formed. And that work has continued and evolved, certainly. But at that point, there was a lot of effort into trying to understand the forces in the earth. I think that's what led in part to the project I worked on.

There'd been knowledge of some early induced earthquakes in Denver, for example, magnitude 6 earthquakes in the 60s that were induced by deep injection of fluids. People did experiments in Colorado out in the middle of nowhere and were able to induce small earthquakes and understand them. I think people were grasping at how to measure the actual forces in the earth then. And we still are. It's kind of an unsolved, difficult problem. There's understanding earthquakes, but there are also very practical issues. If you drill a bore hole, is it going to stay open, or is it going to collapse? Things as simple as that. And that depends on what the forces are. That's just one example of what applications could be on a practical side.

ZIERLER: How much did you rely on synthetic samples for your research, and how much was the result of field research, going out and getting stuff yourself?

SCHMITT: In the Lab, it was all synthetic samples. I'd get measurements on things like crystalline quartz, fused quartz, glassy quartz, sodium chloride, potassium chloride, things like that. That was all synthetic. I actually did field work with Tom, and we went out to Rifle, Colorado. At the time, Union Oil was trying to get oil out of material called oil shale. It's actually probably not even energy-efficient. You had to find it, then cook it, then you'd get oil out of it. It was a really dirty process. They had a mine, they let us go in, there was a mine pillar, and with this instrument we made with the optical holography, we made measurements in it. We got good data for sure. I went out twice. Actually, Tom went out once that the field. [Laugh] But I wasn't really bringing in samples to work on. There was a bore hole, and you'd put in a specially designed instrument. That's probably where I got the sense that you actually had to go out in the earth and probe it to better understand what's going on.

ZIERLER: What were some of the principal conclusions of your thesis research?

SCHMITT: I guess on the shockwave side, it was measuring melting temperatures of these different minerals up to pressures that would be about 200 kilometers deep in the earth. The sodium chloride was maybe a more physics based one, studying what temperature the salt would melt at. Because people would need that data to try and understand theoretical models better for melting. At that time, the big computers weren't around. There's been a lot of growth in understanding of those processes since. But at the time, people were still grasping, using thermodynamic arguments and that to try and understand what's going on. In the stress one, we got data, and I'm not sure we made any fundamental conclusions from that, but we demonstrated the technique could work. I kind of went away from it because I went and did a post-doc, working on bore holes, and that's where I learned to work on rock properties more, too.

But at Caltech we all assumed that when you drill a bore hole, it'll be this perfect cylinder going into the earth. In reality, what happens is, the rocks fail, there's a lot going on. It's actually an extremely difficult environment to work on. Some of the people who helped me, the technicians, were great people, but they'd done easy things like put seismometers on the moon. If you have to put something in a bore hole under pressure and temperature in something that large, it's a very different kind of situation. It was excellent training for me to understand the problems of the stresses in the earth, but I'm not sure I got much of a conclusion out of it. But it did lead me into other aspects of it, so I can't really complain. [Laugh]

ZIERLER: When you went to Stanford for your post-doc, was that specifically to pursue new interests in mineral physics?

SCHMITT: No, it was the stress [measurement]. There was quite a well-known guy named Mark Zoback, and he was a brand-new professor. He'd been at the USGS for a decade or more, doing a lot of research on stress measurement in the earth using techniques like hydraulic fracturing, small hydraulic fractures, where you just make a crack, and you can interpret those curves to understand the forces. By the time you've done your PhD, you've had enough sometimes of what you are working on. I thought, "I've got to find a new method." I went there because I assumed that this hydraulic fracturing would be the golden key to understanding stress. And of course, it's not either. But that's what drove me. I went to Stanford, and that was great. I learned about bore hole geophysics, and at the time, they had a world-leading rock physics lab to understand the physical properties of rocks. As I said, I torture the rocks in the lab now, so I learned a lot of the techniques and picked them up there, being exposed to how to make rock property measurements. Then, that kind of grew when I expanded to Alberta. But that's what I got out of Stanford. It was more rock physics. As I said before, from my perspective now, I kind of see myself as a rock physicist who just uses both field and laboratory techniques to understand how rocks behave under different conditions.

ZIERLER: How much of a new direction was your post-doc? What was relevant from your time at Caltech, what was totally new to you?

SCHMITT: Stress measurement was the broad theme, but the techniques were completely new to me. The hydraulic fracturing, working with pressure systems, learning how to carry out measurements in bore holes. And again, they let me do things that I would never let a post-doc do who didn't have the experience, but it was different times. There was a bore hole on the San Andreas Fault, Cajon Pass on the way up to I-15, when you're going up the hill. There was a bore hole drilled there, and they let me log with a simple instrument at 7,000 feet depth, running this huge truck all by myself after a day of training. [Laugh] You just don't do that today. Things were a lot easier in those days. But there were those techniques, then there were the rock property techniques in the lab. It was complementary but quite different, a new direction.

ZIERLER: Tell me about the opportunity that came up at the University of Alberta. Is it a large program in geophysics?

SCHMITT: Yeah, it is. I'd already had two job offers back in Canada in other universities. Then, EOS had this ad out from University of Alberta, and my family is from Alberta, so I applied to it. They flew me up right away and interviewed me. The job was for an experimental seismologist, which I've never seen anywhere else before or since. I'm an experimentalist. I probably wasn't the best at seismology because I'd never done it, but I learned a lot, applied the techniques I learned at Stanford, built up a lab, carrying out shallow seismic measurements, bore hole seismic measurements. I even got a seismic vibrator truck that I brought with me to Purdue. The seismology gives me a really nice way to test, if I have a bore hole in particular and can put sensors into that bore hole, how the waves go through the earth. Then, that allows me to study those waves and figure out what's actually happening with the rocks where they live. That's what happened at Alberta, moving to applied seismology more. Or I should say active-source seismology because a lot of the projects, when really applied, were different. Like Chicxulub Crater.

ZIERLER: What does that mean, active source seismology?

SCHMITT: At Caltech, Rob Clayton would work with active source. You use a human source, like dynamite or this vibrator truck I have. I take the vibrator truck, and we vibrate the ground a certain way, then we listen to the vibrations. Most of the Caltech people would've been using seismometers that sit there and listen all the time, waiting for earthquake waves to come in passively, whereas active source, you're controlling the source, and you control where the sensors are. Then, you can use that to image into the earth. You never hear about applied geophysics and seismology, but it's actually a high-tech industry that consumes a sizable fraction of the earth's computing power to make these images of the subsurface, primarily for the petroleum industry so they know where to drill. Through risk reduction, there have been billions and billions of dollars spent developing these methods to image into the earth. What's exciting right now a little bit is that those two are starting to merge. And I think they should've a long time ago. The modern sensors we use now are all passive. They sit for a month. But you'll run around with your seismic source, and activate it, then take the data off. In the applied field, the concerns about human-induced seismicity, where you have sensors, and you have to listen to little earthquakes that come in, have really taken off in the last decade. The more applied community and earthquake-based community are started to merge more and more, so it's kind of an exciting time. Both have good ideas but have kind of lived in different silos. I think it'd be a really good cross-fertilization.

ZIERLER: I'm curious if the growth in computational power was significant enough that it sticks out in your memory over the course of your research career where it really became a vital tool for your work.

SCHMITT: Oh, yeah. I'm not a modeler, I do very little modeling, but just seeing the capacity for what we can model now, all the way from minerals to large imaging of the earth's subsurface, you can't live without it. But that was already starting by the time I became an assistant professor. You couldn't live without a computer. It's been around for a long time. But the fact that it's becoming more easily accessible to more and more people, the high-level computational routines, modeling of wave fields, modeling of stresses in the earth, things like that, where you need very large computational resources, I think that's another positive thing. I need to learn more about that myself. I'm not the best modeler, like I said. But I've tried to make sure my students know how to use those advanced computational techniques now because they can't live without it going forward.

ZIERLER: I asked earlier about sustainability in a contemporary context. In the historical narrative, you were, of course, at the University of Alberta right at the time when climate change and sustainability really started to come onto the horizon. Did that affect things in real time for you and your students?

SCHMITT: I'm going to back up right to that time when I started being an assistant professor 30 years ago, when you first heard these inklings about CO2 being important in a more general way. It did, I think, have an increasing amount of influence through my entire career since then, particularly with the geological sequestration of carbon. I've probably been working on that for over 15 years now in various aspects, in the lab and the field. It started to become important, for sure. I was in Alberta, which of course is the oil sands or the tar sands, and I did some work there for sure. It's still a fantastic resources, and we need to get it out, and we need to do it properly. What always made me angry a little bit was the way particularly the government in Alberta would hide away a lot of it instead of being transparent when they could've been about how much pollution they were producing or whatever. If they'd been more transparent about that earlier, I don't think Alberta would be seen as the bad boy of the planet.

And that made me angry 20 years ago, the way things were being handled. Maybe I should've stood up earlier, but I was a professor. [Laugh] It was hard to make progress. And maybe it's been on my mind even before many of the other ones who were in a more pure academic mode because I could see what was happening there, that there were important things that needed to be done. It's still an incredible resources, and we're going to need it for the next thousand years because we're going to need these hydrocarbons still in one form or another. Not to burn them, hopefully, but for other things.

ZIERLER: Like what? When you say other things besides burning, what do you have in mind?

SCHMITT: Petrochemicals, stuff like this. In fact, some of the early people who looked at the oil in, say, the 1850s said, "Oh, this is too valuable to burn." It's a very dense kind of chemical organic. And maybe we can reproduce all of it other ways. But I think it's still going to be around and needed in various forms. Although, we shouldn't be burning it. I think what kind of angered me back in that timeframe was just the avoidance or the lack of monitoring. And we see this today, still. If you don't monitor something, you don't know about it, and therefore, it's not a problem. Those kinds of things, the lack of transparency, probably hurt the whole image much more than anything else did, really, because they weren't upfront about things. That's changed. Now, the oil companies actually are probably much further to the left of the government. [Laugh] About a month ago, I went to an event and heard old tropes such as, "We're only 1% of the problem. Why should we care when everybody else is doing this?" And I still hear those same exact arguments today. In Indiana, where I am now, I got this emergency call to come down for a state senate hearing about a month ago in which they were to deal with CO2 sequestration.

As you know, Indiana is a rather conservative state. [Laugh] I heard the exact same words coming out of very similar people. They were dealing with an issue that had to do with CO2 sequestration –there are a lot of legal issues dealing with sequestration of carbon underground. Who owns the pore space? These issues were dealt in other jurisdictions, like Alberta and probably Illinois 15 years ago. But they were avoiding these issues in Indiana. What pushed them was some of the big companies wanting to have hydrogen here to make steel. We still can't make hydrogen from solar and wind yet. It's just not efficient. We're going to have to make it from methane, which will produce CO2, and we've got to bury that carbon dioxide. This was being pushed from industry because they want to de-carbonize as much as they can here in Indiana. Finally, these guys were saying, "Why should we worry about this?" Just listening to the politicians, the same old things.

It was just a hearing, so I don't know how the final vote went, but they agreed to allow certain things to move forward to allow carbon sequestration to move forward. Here, they've been ignoring it, and still are, climate change. If you have a certain political view, you almost have to say certain things, which is really unfortunate. But I think it's breaking outside of this control. Enough of the big companies know they're going to lose business globally. And it comes down to money, unfortunately. But I think things have changed. That's why I said earlier, I think we're going to see an awful lot of CO2 sequestration and that coming forward.

ZIERLER: Tell me about your tenure as a Canada Research Chair. What responsibilities did that entail?

SCHMITT: It gave me a little bit of a reduced teaching load and a little bit more resources. Again, I was able to pretty much do what I wanted. The Canadian system was a little freer that way than the US system in that I think you can direct your own research much more, whereas here, you've got NSF, you've got to be buddy-buddy with everyone. I think it's harder in the States, I hate to say, to find that more innovative path because you're kind of somewhat guided by all of these people, say, at NSF or whatever and what they think is the good thing or the hot thing to do. There's a real herd mentality sometimes. But they gave me some resources that allowed me to get a pretty good number of students and to test out some weirder things. Some of those fundamental measurements I said of testing, say, how waves reflect from earth materials. I would never get funding for that from NSF. And I could never get it from the DOE because it's too basic. I think it allowed me to do some kind of more crazy and innovative things. That was the good thing about that.

ZIERLER: I'm curious because we need China as an energy partner in more ways than one, when you worked as a visiting professor there, what did you learn about the Chinese approach to hydrocarbons?

SCHMITT: I teach a course at China University of Petroleum, but I've also been very lucky. I visited a lot of places in China as part of the drilling. That's hard to say because I never really was involved that much with their industry but with the professors and students at the schools. What I will say is, and I think this is the whole country, they're putting enormous resources into developing their geophysical technologies and training large numbers of people. In this field of rock physics I talk about now, I think there are more people in China doing rock physics than the rest of the countries combined. They have the labs, the support. Sometimes not all of them know what to do with what they've got. Fantastic equipment, whereas others do. And they're getting better and better. They're on a real roll to develop their economy. There are 600 million people in China who are still living in abject poverty, 400 million that are doing pretty well, coming more towards our living standards, so they still have a ways to go. Right now, I think they're getting energy from wherever they can get it, whether it be coal, gas, oil, or wind. Aside from COVID, I'm teaching a new course on energy. I shouldn't say anything, but I'd like to get some kind of textbook out of this on fossil fuels, energy, and society, which is the course I'm teaching.

Just to see how much of the resources are being consumed by China, that course has given me this opportunity to kind of overview a lot of that, how much coal they're using, how much gas, all of this, to grow their economy. We've benefitted from that in a way. They're producing a lot of CO2, but they've shipped all the stuff to Walmart. Really, we're not guilt-free in growth of emissions. But China is really on the move. It's just phenomenal growth, amazing what they've been able to put together in this last 15 years in terms of the cities. I was in Chengdu, and they just put in a ring road in a couple of years. Here, the lawyers would be arguing for the next decade. You just can't do that in North America. They put in enormous amounts of subway systems. New York City, they finally put in a new line. How many decades did that take? They're really on a roll, and we've got to get our act together again, try and be more innovative. I think we've rested on our laurels too much here in North America.

ZIERLER: In all your interactions in China, is your sense that most people recognize the connection between climate change and carbon emissions and understand what a strategic threat this is for China and everyone else?

SCHMITT: The people I interact with, yeah, the scientists. I haven't heard anyone say that they don't believe it, for example. They're also taking steps to try and mitigate, so there are big efforts there to look at carbon sequestration, for example. But their economies aren't in the same place ours are, so how much effort they'll put into that right away, I don't know. On the other hand, the way they do things, they could be the ones who get in front of us and develop the technologies if we're not careful. Same with geothermal. Because they are putting enormous resources into all these kinds of fields. I think they realize it. Whether their politicians or businessmen do, they may realize it but not care. I've been in Beijing, where you can barely see the sun. I think there is pressure from the general populace because the general populace are richer now. I heard one Chinese person tell me this: "We're richer now, so we want to have a good life and live a long time." They've stopped smoking and things like this, so they realize the health problems. I think within China, there is pressure to try and clean this up. Whether it works in that system or not, I don't know.

ZIERLER: It's a very complicated issue, but I wonder if you have a sense in talking to scientists who themselves might have an understanding of the political ramifications of how China understands its role between the developed world and the developing world in its relation to responsibility to cut carbon emissions. In other worlds, the industrialized world has created this situation, burning fossil fuels for the past century and a half. Where does China see itself in that narrative in terms of responsibility?

SCHMITT: That's a tough one. I don't know that I've actually ever had that discussion with Chinese scientists. You have to be careful there what you talk about, too, especially now. In the last three years or so, the mood has changed quite a bit. I really don't know. I know they're certainly aware of the problem, and they see the pollution in front of them quite often. But whether that goes then to saying–and China is producing a sizable fraction of the problem today. But whether that then gets linked to, "We need to cut back more," I don't know that I could answer that question.

ZIERLER: Back to North America, tell me about the circumstances leading you to join the faculty at Purdue.

SCHMITT: This is really a hard one. I'd been at Alberta 29 years, and it seemed…

ZIERLER: It was a rather late career move.

SCHMITT: Yeah. It was the second time I'd gotten called, actually. I must've been on some list. Another university had called me, but they didn't give me a chair. I don't know, I was just kind of ready. It'd been 29 years, and it seemed like I'd done what I could. For example, I taught geophysics field school for over 13 years at Alberta, then I'd recently come off that, and I was feeling a bit of a void there. [Laugh] I think I was just ready. I taught the same courses for a long time. In the back of my mind, I might've been starting to wonder, "Is it time to retire?" Then, they called me, I came down, and they seemed to want me. We said, "Let's go for it." I'm not going to say it's been easy because it's worse than being an assistant professor. New teaching, a new system entirely for funding and that. That's been a challenge. And I still have responsibilities back in Alberta. But not everybody gets to give it another go, right? I think it was mostly that, this late in my career. And it's fun because there's a big planetary group here that was actually developed–maybe part of the reason I'm here is because a guy named Jay Melosh, a famous planetary scientist who had been at Caltech but left as a professor before I got there, he knew Tom Ahrens pretty well, seemed to really push for me. I call myself the unconventional Unconventional Energy Chair because I do all these other things, not just hydraulic fracturing and shale. I think he might've liked those aspects. It was a really nice group, I really felt welcome, and I was just ready for a change. We did the jump.

ZIERLER: Did that present new research opportunities for you, being in a new environment to take on different kinds of projects?

SCHMITT: Oh, yeah. Like I said, the planetary people are here, so I'm getting some new collaborations going on that. I'd like to spend more time there, but I'm not sure how much I will. Then, making new collaborations with some of the big CO2 projects, particularly in Illinois, next door. Then, one issue with Canada is that the level of funding for, say, the scientific drilling, it was hard to participate globally like this. I think coming to the States would give me more opportunities to obtain funding to be part of these international drilling projects. There were lots of reasons. I still need to get some funding, but that's coming. You've got to get the lay of the land and get into the network here. It's a lot more network-based. [Laugh] That's taking some time, but it'll come.

ZIERLER: Did you take students with you from Alberta, or you started brand new?

SCHMITT: I pretty much started brand new. But I still had five students in Alberta, and they completed their PhDs, the last one in December. That was the back-and-forth. COVID kind of set things back because even to Canada, we couldn't travel very easily, and they couldn't come down here to work in the lab. They all stayed for a variety of reasons. One had a job. There are no mountains in Indiana, and one of them needed mountains, things like this. Others were close to the end of their PhD.

ZIERLER: Now that we've worked right up to the present, for the last part of our talk, a few retrospective questions, then we'll end looking to the future. First, have you kept in touch with the Seismo Lab over the years?

SCHMITT: Not as much as I should. I kind of keep in touch with Rob Clayton here and there and a few of the others. But it gets harder because a lot of the professors who taught me have now passed on or are certainly in retirement. But I also keep in touch with a number of my cohort from grad school. You kind of get a sense for what's going on there, and you still meet these people at meetings. I'm not sure I know exactly who the young professors at Caltech are. [Laugh] I've gone in a different direction. Some of them probably say I've gone in the wrong direction, but I don't care, I've had a great time. We're doing more applied work, near-surface work. But I've kind of maybe lost touch with the younger professors, but I try and keep some tab on what's happening there.

ZIERLER: Exactly on that point, because you have switched up your career focus over the years, I wonder what you might have learned at the Seismo Lab in terms of your approach to the science or in terms of collaboration that might've stayed with you, no matter what you went on to do.

SCHMITT: Dr. Tom Ahrens is a pretty intense person. I may not be outwardly intense, but I think the intensity to focus on a problem, try to get into it, to try and get the physics right, the basics, trying to understand it, then a lot of the, say, technical skills, you don't stop those, you keep developing them your whole life. I think that's what Caltech basically gave me. The other thing was a really great group of grad students. I talked about the three projects you have to do in the very first year with three different professors, then you presented those to a committee of some of the professors to see if you should continue in the PhD. But before that, the group of graduate students and post-docs was extremely supportive. Before you went to your exam, all of them or a very large number of them would come, they'd sit down, and you'd present what you were going to present to the professors. The students would pretend they were the professors, give you a hard time to help you for that exam. Even though you weren't collaborating directly with each other on a project, you were getting a sense that there was support and how to try and build a supportive community. I think that was something I really gained. Then, when I went out into the world, I tried to build communities like that elsewhere, but it's impossible. A lot of type-A academic personalities. [Laugh] But at Purdue, there is some of that element again, and that's really nice, to come back where everybody seems more supportive, trying to have their, "My grad students are here, and your grad students are there," kind of thing. Even though I wasn't successful, how to possibly build a really supportive kind of community. Then, just the technical aspects that I learned from.

ZIERLER: Finally, for you, looking to the future, given all the twists and turns that your research career has taken, what might you take on next that you haven't yet?

SCHMITT: I don't know that I'm going to have huge shifts in what I'm doing. What's exciting to me right now is, if we go to hydrogen storage in a big way, how to ensure that's done safely to contribute to that from more of an applied perspective. From the more academic perspective, we collected seismic data near this Kentland crater. I've worked on four craters so far around the world. It could be, hopefully before I retire, there will be a project where we go to Barringer Crater or Meteor Crater in Arizona, and redo a lot of the geophysics there, and drill maybe. That's a simple crater, and that would be one kind of offbeat project that would interest me and that I'd hope I could contribute to.

ZIERLER: Doug, on that note, it's been great spending this time with you. So glad we were able to get your experiences and perspectives from the Seismo Lab days and everything else. I'd like to thank you so much.

SCHMITT: Thanks a lot, David.