Mark Richards (PhD '86), Seismologist and UW Provost

From his small town roots in Texas to his current responsibilities leading academic affairs at the University of Washington, Mark Richards's graduate work at Caltech's Seismology Laboratory led to a wide-ranging research career in geophysics and seismology, and ultimately, to academic administration. Richards has investigated the large-scale dynamics of Earth, the moon, Mars, and Venus; rotational dynamics and global plate motions in historical perspective; the geological evolution of the Galápagos Islands; and the role of geological process in mass extinctions.

After completing his undergraduate degree at UT Austin, Richards pursued graduate research at Caltech's Seismo Lab, where he worked with Brad Hager and Tom Ahrens (MS '58). His thesis examined the fundamental question of how to understand the large-scale structure of thermal convection and dynamics in Earth's interior and plate motions. Subsequent to Caltech, Richards joined the faculty at the University of Oregon before transferring to UC Berkeley, where he served as chair in the Department of Earth and Planetary Science, dean of mathematical and physical sciences, and executive dean for the College of Letters and Science. He has served in his current role at the University of Washington since 2018.

Richards is a fellow of the American Geophysical Union and the California Academy of Sciences.

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It's Tuesday, May 31st, 2022. I am very happy to be here with Dr. Mark Richards. Mark, it's great to be with you. Thank you very much for joining me today.

MARK RICHARDS: Looking forward.

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

RICHARDS: I am currently the Provost and Executive Vice President of the University of Washington.

ZIERLER: What are some of the exciting things that are happening at UW these days?

RICHARDS: It has been an exciting couple of years with COVID. We were the first university in the country to go 100% remote because the state of Washington was the first to be really hit hard by COVID, so the last two years have been anything but normal. As a general rule, the University of Washington is doing very well compared to peer R1 public universities. Lots and lots of things going on that are exciting. We have advances in everything from quantum computing to precision medicine and all sorts of activity on campus in terms of race and equity and justice. We just hired last year by far the most diverse group of faculty we've seen at least in living memory. Depending on who you count, between 27% and 31% of the new tenure-track faculty we hired were underrepresented minority faculty, mostly brown and black faculty, and that was a huge increase over previous years. It wasn't by accident; we put a lot of effort into that.

ZIERLER: Has your own research agenda been able to stay on track during all of these turbulent years?

RICHARDS: I became a dean at Berkeley in 2002, and that seems like ancient history now, which I did for 12 years before I went back to regular faculty duty for four years before I came to University of Washington. I made a really conscious decision even at that time that there was no way in the world I was ever going to find myself in a position where I got behind in my research in such fashion that I couldn't go back to being regular faculty. That if I had to give up administration or research, I would give up administration tomorrow.

The other thing—I would say this is particularly true at Berkeley—is that deans are expected to stay active as scholars and researchers. It's not true at all places, and in fact, when I came to the University of Washington, that was sometimes true but not often. But you know what? It creates a perverse incentive. You spend seven or ten years as a dean, you get out of research, and then what do you do? You either continue as a dean or advance in administration, or you're done, kind of, because it's really hard in sciences as well as other fields—once you get out of it, it's hard to get back on board. So I always, for the last 20 years, have made sure that I squared away time to stay active in research.

When I went back to the faculty at Berkeley for four years, from 2014 to 2018, regular faculty, that was sort of the most productive research years of my career, actually, and it was great! Kind of had a new perspective. I remain active now. I think I sent you the David Attenborough clip—

ZIERLER: Yes.

RICHARDS: I don't know if you saw it. I don't know if you took the two hours to watch the entire thing.

ZIERLER: I did.

RICHARDS: Did you? As science documentaries go, they did a pretty good job.

Leadership at the University of Washington

ZIERLER: Now, what is your home faculty appointment at UW?

RICHARDS: Earth and Space Sciences. I'm basically a geophysicist, but the department at UW is called Earth and Space Sciences. My department at Berkeley was called Earth and Planetary Science, so quite similar.

ZIERLER: With all of your administrative responsibilities, do you have a research group? Do you have grad students? Are you able to teach at all?

RICHARDS: Marginally. Most of the research I do I would say is with colleagues rather than students and postdocs. At Berkeley I always had a graduate student and a postdoc or two even as an administrator. At UW, I had a postdoc who just got a great job at NASA and just left, so I do have postdocs. I haven't had any graduate students at UW. I am going to teach. As a matter of fact, I'm going to teach a course on Earth history this coming year. It's not part of what I'm supposed to do as an administrator, but I like teaching. I actually have another motive, which is that I'm going to spend a lot of time setting up this course. It's going to be a winter quarter course on History and Evolution of the Earth. I'm going to put a lot of time into this between now and winter. It's stuff that I've taught at Berkeley before. This particular version is going to be for non-majors, but I'm going to put together the course under what's called universal design. I don't know if you know what universal design is, but this is a set of principles—it originated in architecture for ADA access, but this really has to do with making the way you teach a course accessible to a broader range of students—students with disabilities, students who need occasional remote access, et cetera. It's kind of my way of walking the walk of what all of our faculty have been up against for the last couple years and something I'm kind of curious about. And, I enjoy teaching. I like students.

ZIERLER: Over the course of your research career, when have you been more on the theoretical side, and when have you been more on the observational and experimental side?

RICHARDS: I would say I have done experimental work. I had a lab at Berkeley for a while for experimental fluid mechanics and geophysics, but I gave that up. That's one of the things I let go when I was dean, because I didn't want to have to maintain a lab. I would say most of my work straddles the observational and theoretical side of geophysics, which is that I don't necessarily develop a lot of theory per se myself, but I use a lot, and I spend a lot of time in the field with observers. There's no particular reason that you could point to why I actually needed to travel to North Dakota to see that site, to do what was I was doing, but in another way it makes all the difference in the world. You know what's real. You get to talk to people in the field. I really enjoy that. It gives a certain sense of adventure. I've worked in North Dakota. I've been working in the Galapagos on and off for three decades, and I've got a new project there hopefully that's about to get funded. I work in India, in volcanism in India as well. That's why I got into geophysics, so I could go out and have fun.

Volcanism and Mass Extinctions

ZIERLER: Is volcanism a one-off project in India, or have you always been interested in volcanos?

RICHARDS: Always been interested. I started to get interested in the certain style of volcanism that we associate with features like Hawaii and Yellowstone, otherwise known as hot-spot volcanism or intraplate volcanism; that is, volcanos that are not clearly associated with plate boundaries. For example, familiar plate boundaries volcanos to you might be Mount Saint Helens, Mount Shasta, Mount Rainier on the West Coast, Fuji in Japan. These are all associated with convergence or subduction zones where one plate is going underneath another. That is the most common subaerial form of volcanism. The most common form of volcanism on the Earth occurs at mid-ocean ridges for plates to spread apart. I don't work on that so much. But this intraplate volcanism is interesting because it comes from the Earth's deep interior and what we call mantle plumes or plumes of hot stuff rising probably from the core-mantle boundary. India is an enormous outburst, what's called the Deccan Traps, which was simultaneous with the extinction of the dinosaurs, which still remains one of the great geological mysteries of all time, is we have one mass extinction and two causes. The Deccan Traps eruptions, which occurred at the initiation of a new mantle plume that is now currently active at Reunion Island in the Indian Ocean. Of course, we have the Chicxulub impact at the same time. In fact, one of the recent controversial papers that Walter Alvarez and I wrote together was suggesting that the two might actually be related, in an odd way that I won't spend a lot of time going into, unless you want to.

ZIERLER: What's controversial about it? What are some of the orthodoxies in the field that you were trying to shake up?

RICHARDS: I'll give you a little background. The last four major mass extinctions in Earth history are all closely associated in time with enormous volcanic eruptions of this style. The largest mass extinction we know of occurred at the end of the Permian period, the Permian-Triassic boundary, and that's associated with an even larger set of volcanic eruptions in Siberia known as the Siberian Traps. The one just before that, and the one just after that, at the end-Triassic, was also associated with a large—we call these flood basalt events, because they're literally floods of lava. The Deccan Traps in India would have covered the state of California in about a kilometer-thick lava formation in less than a million years, to give you some idea of how big these things are. The—what geologists call a uniformitarian view—would say, "Obviously the mass extinction at the K-T boundary, the end of the dinosaurs must have been associated with these volcanos in India just like the others." And yet the evidence is that this large impact and Chicxulub crater, Northern Yucatan Peninsula, is actually the cause of the extinction.

Then you have to say, "Could there be some crazy way that the impact and the volcanism could have been related? Could the impact have triggered a volcanic event?" That's something people have speculated about for a long time. Generally, the answer is no. I don't know if you know who Walter Alvarez is; he discovered the Chicxulub impact, and he's my closest friend on the faculty at Berkeley, still. For 30 years, we've been scratching our heads over this perplexing problem. What we suggested in our 2015 paper is that there seems to be evidence that—the Deccan Traps eruptions in India were already occurring at least a million years before, or probably more, than the extinction boundary and the impact, so we know that the impact didn't cause the volcanism fundamentally, but we did find evidence that the volcanism accelerated the volume rate of flow, and also the geochemistry changed at that time. We wrote a paper suggesting that the impact may well have shifted the mode of volcanism and caused it to accelerate and therefore perhaps contributed to the mass extinction. This is a problem I've been working on since then. The tests that we did, I worked with the Berkeley Geochronology Center. We did very high-precision argon-argon dating of the formation. Actually the formation is right around the time where we predicted that this change in mode might have occurred. Lo and behold, it comes out within 30,000 years, the precision of the method, of the K-T boundary, of the impact, actually. That's something we're still interested in. It's controversial. I'm not wedded to the idea, but I'm certainly curious about it, and it has been a lot of fun.

ZIERLER: What are some of the missing links experimentally, observationally, that might bring finality to these debates?

RICHARDS: That's a multifaceted question. In terms of the mass extinction itself, there is little evidence that Deccan volcanism, in this particular flood basalt event, caused the extinction. There is a lot of evidence that the impact actually did, as per the video that you saw, in that particular location, although some of that was a little bit exaggerated in those terms. Less glamorous than the dinosaurs is that the microfauna of the oceans, the foraminifera extinction, which the ones that are planktonic—that is, the ones that are in the upper ocean—over 70% of those species went extinct very suddenly right at the iridium anomaly from the impact, so the microfaunal extinction was certainly not a result of a more gradual process of volcanic outgassing. Whether or not the dinosaurs as a whole—clearly the whole ecosystem was being stressed, because both of these things are going on at the same time. On the other hand, the evidence from Deccan is that the largest carbon dioxide and halogen gas emissions, which probably is what led to other mass extinctions from large volcanic events—the peak of those emissions was well before the K-T boundary, at least from what we see now.

Then there's also just a need for more and better geochronology. The other problem is that we think up to two thirds of volcanism associated with the Deccan eruptions are actually located offshore India to the west. There has been a good bit of seismic exploration in some bore holes drilled out there looking for oil deposits beneath the lava flows, but we haven't been able to get access to the Oil and Natural Gas Corporation of India's well log records and samples. We would give our right arm to be able to date some of those samples, because it's a big missing piece. We've got another decade of work before we get to some of these answers, but it's pretty fun. It's really fun stuff. Everybody loves the problem of the dinosaurs. Even David Attenborough. When we were filming that last July, the BBC film crew did not know at that time whether Attenborough was going to agree to do the narration. He only agreed to do it because he thought it was fun. [laughs]

ZIERLER: Some technical questions that you've pursued over the course of your career. First of all, computational geophysics, did computers reach a level of power at a certain point in your career where they became really viable to answer some of the questions you were after, or have they always been part of the equation for you?

RICHARDS: Fortunately, I came into geophysics with a good bit of background in computer programming. Not so much numerical analysis, but I learned that. I would say that in my business, in geodynamics, computational models of what we call convection, in the Earth's interior, and plate tectonic type behavior became fashionable in the 1970s, but the computing power was very lacking. By the 1980s, we were able to do things, numerical models that simulated aspects of plate tectonics that had sufficient resolution, but only in two dimensions. Earth is a three-dimensional planet; it's spherical. It wasn't until the 1990s that we had the computational power to really get close to doing the problem right with appropriate resolution. But over the last 20 years, it has become—I would say that we folks who do computational models in geodynamics are more limited by our imagination than we are by computing power. I have always had a pretty firm insistence that I don't really like output from numerical models that I can't understand ultimately on the back of an envelope. Again, that's kind of my bent toward combining theory and observation, computation. I don't like to get very far away from things that I can translate directly with common sense. So, I would say that the computational power we have right now is being put to great use by a few groups, at least, but I would say that I don't view computing power as a limit on what we're doing now.

ZIERLER: What areas in either or both continental drift and plate tectonics remain open questions that you've pursued from that perspective?

RICHARDS: Continental drift is kind of the older version. We don't really talk of that as a modern theory anymore, because it was based just on the notion of the magnetic sea floor record. But plate tectonics more generally, there are some things that we understand pretty well, I would say, which is that we understand the nature of what we call the oceanic lithosphere or plates, how they cool and thicken as they move away from ridges, and how their buoyancy changes, and therefore why they sink at subduction zones and things like that. But we don't understand very well yet—well, some people think we understand it better than others; I would say that I am on the side that we understand some things pretty well—that the primary driving forces for plate motions is probably derived from subduction zones, that is, where plates sink, because we view the ridges, where they spread apart, as largely passive features. I could spend a lot of time talking about why that is, but we don't think that those ridges are generally underlain by active upwelling structures. In fact, the active upwelling structures are what I was talking about before, these mantle plumes, but they do not explicitly seem to drive plate spreading motion. Although you do find a lot of mantle plumes near ridges, so it's kind of a complicated story.

There are other questions about whether or not there is some degree of chemical heterogeneity and layering in the mantle—whether, for example, the deeper mantle below, say, 1,000 kilometers or so, is inherently more dense, intrinsically more dense, and therefore resistant to kind of whole-mantle mixing. The evidence that that may be true is pretty weak. On the other hand, we know that to some extent it has to occur because there's lots of chemical heterogeneity in the mantle and the dense stuff is always going to be preferentially sinking. The question is, is that dynamically important? There's still a lot of questions out there. I'm sure if I had a half an hour to think about it, I could tell you a whole bunch more.

The other thing that I think is really often forgotten and fascinating is that we have two neighborhood terrestrial planets, solid planets—Venus and Mars. All three—Venus, Earth, and Mars—their tectonic regimes, so to speak, are completely different from each other. Mars is a one-plate planet, Earth has plate tectonics, and Venus has characteristics of lots of lithospheric or—the upper surface is very dynamic, but we don't see the character of plate motions that we see on the Earth. We see more continuous deformation. Probably the biggest thing that sets at least Earth apart from Venus is that we have water, both at the surface and in the rocks on the Earth, that creates a zone of weakness beneath the plates and allows the plates to move around with some independence. The problem of planetary perspective—why do we have plate tectonics on this planet, which we happen to be here—we evolved on this planet, and we probably evolved on this planet because there's water here, and the cycling of water into the deep interior is probably in no small part responsible for plate tectonics, so the fact that we live on a plate tectonically active planet is not an accident. The question is how common is that, how unique is the Earth. When we look at extra-solar planets, should we be looking for those characteristics as places that might harbor life?

ZIERLER: Intellectually and academically, your interest in tectonics beyond planet Earth—Venus, Mars, even the Moon—to what extent is having that different perspective valuable for better understanding the Earth?

RICHARDS: We have a whole bunch of stars out there in the galaxy. If the only star we had teaching us something about star formation and dynamics was our own sun, we would be greatly lacking in perspective. The same applies to planetary dynamics. It's great that we get to look at these other solid bodies in the solar system. Obviously Neptune and Saturn are fluid bodies, but they have satellites. They have some large satellites that are solid bodies, that have different—none of them show plate tectonics, really. One of the satellites of Jupiter is Europa, which is covered in ice, and that ice shows platelike behavior over an interior that's largely liquid. Our own Moon has different dynamics, has a different internal history. It has been largely dynamically inert for the last few billion years. So, they're all different. I can't think of two solid bodies in the solar system that actually resemble each other that much. It's pretty remarkable. It's just that you would not have much perspective on our particular situation without these other examples.

ZIERLER: You mentioned Europa and the possibility of tectonic activity there. There's also quite a bit of excitement, as you well know, about astrobiology and the possibility of microbial life on Europa. Perhaps that's connected in the way that you talk about the origins of life here.

RICHARDS: Possibly. I have to say that that's an area that I haven't covered so much. I've had students who are really interested in that. It's just an area that I haven't spent an awful lot of time on. But if I were a young scientist in the field, I'd certainly be focused on that. Then there's Titan, too, of course, which has I guess methane in the atmosphere, and all sorts of reasons. I think Titan may be NASA's biggest target right now for probing for extraterrestrial life other than Mars itself, of course. There are indications that Mars in its early history might well have supported life; not directly, but in terms of the conditions that were there.

From Austin to Caltech

ZIERLER: Let's set the stage. Prior to your graduate study at Caltech, when you were at UT Austin, was geophysics on your radar at that point? Were you interested in that?

RICHARDS: Not at all. I probably should start earlier than that, to really help you understand this. I grew up in a small college town in East Texas. At that time, it was called East Texas State University. My dad was a music professor there, and my mom was a piano teacher and organist. I was good at science and math at school. My mom was actually a math major, too. Everything I did seriously before I went to college had to do with music. I played a number of instruments. My older brother is a professional musician.

I got offered a scholarship at UT Austin in, of all things, chemical engineering, just because they picked my name out of a hat or something like that and I had good SAT scores or something. I went there and I said, "Well, sure, I kind of want to learn something about the non-musical world." I was interested in science, and engineering sounded interesting. I very quickly realized that I didn't like chemistry that much, after I got there, and I gravitated more toward the physics side of things. I ended up with an undergraduate degree called engineering science, which was really kind of a "roll your own" degree program. I would say that about half my courses were in physics, and about half were in electrical engineering. I was interested in plasma physics and lasers, and I was interested in perhaps working on nuclear fusion power. This was back in the mid 1970s.

ZIERLER: The big promise of fusion was right around the corner.

RICHARDS: That was 30 years away now, right? At that time, people were saying, "Well, maybe it's only 10 or 20 years away." I was excited about that. I came to Caltech as a grad student. I wasn't sure I wanted to go to graduate school at the time, so I applied only to Stanford, Caltech, and MIT. I hadn't really thought of applying to Caltech; the only reason I did apply to Caltech was that there was no application fee.

ZIERLER: [laughs]

RICHARDS: That's literally true. It turns out that I was probably headed toward MIT, because they had a well-known plasma physics group there, but Caltech offered me a better deal. I visited all these places. MIT kind of went out of their way to say, "Only about 40% of the students who start in our PhD program finish. This is a tough place." Et cetera. When I interviewed at Caltech, they said, "Hey, congratulations. The hardest thing about getting a Caltech PhD is getting admitted." I thought that was a good bit more attractive proposition, and so I came in applied physics. I started, and I spent two years. I eventually decided that wasn't what I wanted to do, but I got a master's in applied physics. My advisor was a guy named Bill Bridges, who has since retired. He invented the argon ion laser when he was at Hughes Research.

Also, when I came to Caltech, I fell in with a group of friends about half of whom were French graduate students who were expert mountaineers and alpinists. I started going mountain climbing every other weekend, and I kind of discovered how much I loved being outdoors and hiking and climbing and stuff. Then I met a couple people who were on the geophysics or geology side, or in the Division of Geological and Planetary Sciences. They were also from a similar background as mine, either engineering or physics, but they got to do it outdoors. I like to say to people, "It's like doing physics outdoors."

I left graduate school and I went to work for a year at Jet Propulsion Laboratory. I worked on the Seasat project, which is remote sensing of the oceans. What I had in mind actually was to apply to Scripps Institution of Oceanography and do physical oceanography. I ended up coming back to Caltech, but I spent the intervening summer studying classical guitar in Spain for the hell of it, but that's a distraction. When I was working on the Seasat project, I learned about using satellite geodesy to map the Earth's gravity field. I don't remember exactly how this happened, how this connection happened, but a new professor was arriving at Caltech that following summer named Brad Hager, who a long time ago left to go to MIT, and he was interested in doing what we would now call geodynamic modeling of the Earth's gravity field, the long-wavelength field and the relationship to the structure of the Earth's deep interior.

The Seismo Lab made me an offer to come back, which I still regard as kind of bizarre. At that time in my life, I had never had a single course in Earth sciences, much less geology. Other than what I had learned at JPL, I knew very little about the Earth. But it appealed to me, so I decided to do that instead of going to Scripps. I don't know if that answers your question or not, but that's the route I traveled. I would say that I still think like some combination of a physicist and an engineer. I have both in my background and I kind of flip back and forth.

ZIERLER: How much of a crash course, how much of an autodidact did you need to be, to get up to speed at the Seismo Lab?

RICHARDS: The Seismo Lab was a unique environment. There were a number of students who had come from backgrounds not all that dissimilar to mine. The Seismo Lab was all about geophysics. By that time, Seismo Lab was kind of a misnomer, because it was more than seismology, of course. It was very closely allied with the planetary science group. People like Peter Goldreich and David Stevenson were there. Dave may have retired by now. Peter is no longer there. They had lots of students coming directly from physics, a lot of people who decided that they didn't want to do particle physics; they wanted to learn about planets and the Earth. I wasn't so much a fish out of water. In fact, I think my physics background, because I had spent two years in applied physics at Caltech, taking physics courses, my physics background and applied math background was a good bit stronger than most of the students, probably. I won't say most. That's not fair; that would be arrogant. I would say that I had a very strong background in physics and applied mathematics, so that the courses that I took in seismology and geophysics, the hard part is the physics and the math. The Earth science part is not so hard.

However, I was really determined to not be one of those geophysicists who didn't really know much about the Earth. By the time I finished my PhD, I had taken most of the undergraduate curriculum in geology at Caltech—minerology, petrology, structural geology, geochemistry, and even field geology. I attribute that to one very good aspect of the way the Seismo Lab ran things. They had separate academic and research advisors. You had a research advisor—that was Brad Hager—and I started immediately doing research with him that went pretty well. Then I had an academic advisor whose job it was to kind of be an antidote to the selfish motivations of your research advisor who wants you in the lab all day doing research. That was a fellow named Tom Ahrens, who was an experimental geophysicist, high-pressure geophysicist. Tom basically gave me license, and argued with Brad I think sometimes, to allow me to take all this coursework in geology, which no doubt, even though I already had a master's degree, it still took me six years to get a PhD. Almost six years. No doubt, it took me at least a year longer because of that, but it made all the difference in the world in my career, because as a result I became much more independent in defining and seeking my own problems rather than having other people tell me what problems were worth working on.

ZIERLER: What was Brad working on at that point, and what was Tom pulling you away from, as a result?

RICHARDS: I don't want to create the false impression that there was a tension between them, but it's not something that Brad would have necessarily recommended me to do. But I had the support of someone who understood that I was in this for the long haul and I wanted this extra background. Brad was basically on the more theoretical side of what we call geodynamics, geophysics, although I would say that he, too—and I learned a lot about this from him; he was a very good advisor—was very much in the same vein of combining theory and observation. There's kind of a school of geodynamics of people who do that, as opposed to another school of geodynamics at the time that was very focused on mathematical and numerical modeling per se.

At the time, Rob Clayton at the Seismo Lab along with Adam Dziewonski at Harvard, they were developing among the first really decent resolution tomographic images of the Earth's interior, which can be translated with some simple assumptions—they're seismic velocity images, 3D heterogeneity, that you can translate into density heterogeneity. That is, hot stuff rising and cold stuff sinking. Then you can make another—the models that I developed showed how to convert that into models for the gravity field. We produced a paper in 1985. It's a Nature paper. I think Rob Clayton was the first author—and Rob, and Brad, and Adam Dziewonski and Rob Comer, we were all coauthors on that paper, which is a very heavily cited paper that provided the first clear explanation for the long wavelength shape of the Earth's gravity field and the interior dynamics. That was a significant accomplishment. I was fortunate. When you do something like that, and you're a kid, you don't realize, "Hey, this is really a home run," but it was. I ended up doing most of the rest of my thesis focused on those types of problems.

ZIERLER: What were the major research questions that propelled your thesis?

RICHARDS: It was kind of what I described just then: What can we understand about the relationship between the large-scale structure of thermal convection and dynamics in the interior, and plate motions? It turns out that solving that geoid problem, the gravitational field problem, didn't directly address that. It was later that I began work with David Engebretson, Yanick Ricard, some of my own students at Berkeley, where we were able to explain that that large-scale structure, which occurs at a scale that's kind of larger than plate tectonics—if you look at the density structure of the Earth's interior, the seismic structure, at first it doesn't look anything like plate tectonics. You say, "Well, what's going on here? We thought the hot stuff was rising under ridges and cold stuff sinking under convergence or subduction zones." It turns out if you integrate that history over about 100 million years, and you keep track of where all the cold stuff goes, it looks almost exactly like the large-scale structure. I would say explaining that was probably the second major accomplishment in my career. I wrote a paper with a guy—David Engebretson is a guy who does plate motion reconstructions. By using those reconstructions over the last 120 to 200 million years of Earth history, we were able to explain the relationship between the density structure in the Earth's interior and the history of plate motions.

ZIERLER: What were some of the advances in prior generations? In other words, even ten years earlier, both theoretically and observationally, what shoulders were you standing on that made what you accomplished possible?

RICHARDS: First of all, the advances in seismology that allowed this tomographic imaging had been pioneered well before. I've got to be careful about this, because there are so many people who deserve credit, but the one person I think is the dogged pioneer of this field was Adam Dziewonski at Harvard. It turns out that Adam and Richard O'Connell, who was Brad Hager's advisor at Harvard, and Brad, there was a paper—Dziewonski, Hager, and O'Connell—I'm trying to remember when that paper was; I think it was 1977—where some of the early images of internal structure from seismology were used to try to understand the large-scale dynamics and plate motions. That group at Harvard, especially Rick O'Connell and Adam Dziewonski, and of course Brad Hager was kind of their star graduate student, they really set the stage for that.

The 1985 paper was kind of the coup de grâce, because we finally had—I developed the theoretical models with Brad for how you translate density structure into gravity field, and the seismic tomography models had matured. In fact, Clayton used a method of—I guess it's back-projection tomography, whereas Dziewonski was using more normal mode seismology…two kind of somewhat independent methods of seismology, giving more or less the same answer on the density structure. In case you're interested—I don't know how much—I take it you're a scientist, because you're asking good questions.

ZIERLER: History of science. Adjacent.

RICHARDS: Here's the paradox: it turns out that if you look at the large-scale structure, the longest wavelength structure from seismic images of the Earth's interior and the gravity field, that what you find is that the gravity highs, where gravity is stronger, you are looking at low-density upwellings. Now that might strike you as odd, because low density should produce gravity low. But it turns out that when you have a large-scale upwelling, it pushes up the surface of the Earth, which is a compensating mass, and depending on what the interior viscosity structure of the planet is, that compensating mass can actually outweigh the driving mass that's causing the deformation, and you get the extra upwarping - positive topography of the Earth wins, in creating the gravity field. So, the gravity field is a small difference between large numbers. My models were the ones that showed how to explain that. That was a heady time. There were other people, there was a group in France that was doing similar work. I think our work has proven to have more lasting power. There were a lot of very smart people involved, and that was a large quest at that time.

ZIERLER: Your time at JPL earlier, did that plant a seed for your interest in planetary science beyond Earth?

RICHARDS: Yeah. It's funny; I went there as an engineer. I went there because I was interested in oceanography. The Seasat mission was launched to basically explore the oceans, but using an altimeter on the satellite to measure the distance between the satellite and the sea surface. The sea surface follows the shape of the gravity field. I thought I was interested in using this to understand ocean currents and what we call eddies and things like that that you can see gravitationally—large-scale eddies and ocean circulation—but then I got kind of interested in the gravity field itself and what's causing those bumps, other than the ocean signal, which is actually relatively small.

For some reason, I got connected with—I remember I had this odd meeting like in the winter, while I had probably applied to Scripps and was waiting to hear, and I got hauled into the Seismo Lab by Don Anderson and Brad Hager, because they wanted to talk to me about this stuff. They offered me a graduate fellowship on the spot and said, "If you want to come to the Seismo Lab, come back here and work on this stuff." I think Brad was new; he saw an opportunity for a new student who would be interested in what he was interested in. The whole thing is kind of odd. I can't say it was planned, but I can say it was very fortunate. In a way, it is a case where I was kind of just following my nose.

I'm grateful to Caltech. Caltech stuck with me. I bailed out. I left the PhD program in applied physics. They would have allowed me to return in applied physics, because I left in good stead, but then I didn't—the reason I told you that about getting admitted to Caltech is they say the hardest thing about getting a PhD at Caltech is being admitted; at that time, once Caltech admitted you, they didn't like to lose you. They were going to stick with you, even if it cost them some money, and even if they had to be patient.

ZIERLER: It's an investment.

RICHARDS: Yeah, they really saw it that way. I hope that's still an institutional quality there, because it's unusual. Certainly East Coast schools have this kind of washout mentality with both their graduate students and their junior faculty, whereas in the West Coast—Stanford, Caltech, Berkeley—there's more of an attitude of, "We may have to be patient with you, but we're going to invest in you, because we see quality." It certainly worked out really well for me.

ZIERLER: A generational question—I've been fortunate to talk to people who were at the old Seismo Lab, the mansion up in the halls.

RICHARDS: Yeah, I've been there.

Bridging the Old and New Seismo Labs

ZIERLER: Did you feel a connection to the foundational days of the Seismo Lab? Was that history part of your experience, would you say?

RICHARDS: Yeah, I would say that I think the new building, Mudd, was built in 1975, and that's when they moved? I showed up at the Seismo Lab in 1980, so the legacy of the old Kresge lab was still there. There's a joke that when Hiroo Kanamori, who is a very famous seismologist you probably know, when he first came to the old lab, that his office was a converted bathroom. That they were out of space, and they literally turned a bathroom into his office. [laughs] There was another famous old professor named Hewitt Dix who was a little bit of an odd person in the Seismo Lab, because he was an exploration seismologist. He was probably in his eighties, and I kind of bonded—he helped me with one of my three research propositions, actually. Then Charles Richter's office was across the hall from my office until he passed away, at the Lab.

People like Don Anderson, Clarence Allen, all those people had been at the old lab, and there was definitely the sense that—you know, daily coffee was a ritual, probably still is. Don Anderson would go down to the coffee room, the seminar room, and he would sit down in his chair and expect everybody to show up and talk about geophysics. That was definitely a legacy from the old Kresge lab, the sense that people would get together socially and scientifically in this kind of free exchange. Don was very good at that. He did a good job of making everybody feel like there was no such thing as a stupid question. A lot of free-for-all.

ZIERLER: Another generational question: Was data freely shared when you were at the Seismo Lab? In other words, nowadays it all runs over the internet. It almost doesn't matter where you are if you want to access the data. That was certainly true in the Seismo Lab's early years. What about in the intermediate years when you were there?

RICHARDS: Certainly among people within the lab, absolutely. There was no proprietary sense about data that I ever experienced. That was also kind of the beginnings of digital seismology becoming widely available, so the digital records were becoming more available. Kanamori was one of the people really pushing that. Because a lot of the seismograms I looked at and saw at the Seismo Lab were still paper charts that people had to hand-digitize. Literally. A lot of students spent a lot of time hand-digitizing seismograms from earthquake records to process and to model. Thinking back on it—I was just a grad student—I can't speak for the field as a whole, but geophysics as a field is pretty open. It's very international. I never had a sense that people were holding stuff back. There probably were practical considerations of just getting access to data, but I never had the sense that people would hide something or hold something because they didn't want you to scoop them or something like that.

ZIERLER: To foreshadow to your later interests in promoting diversity and inclusivity, in the late 1970s, early 1980s, was the Seismo Lab a place—were there women graduate students? Were there African American Seismo students at all?

RICHARDS: There wasn't much racial diversity at all, but there were women students. I arrived in 1980, so I didn't get there in the late 1970s. I got to Caltech in 1977. I look back—this is something that has bothered me a lot. I have to be really cautious, knowing that you might publish some of this, and I want to be careful what I say. The Seismo Lab at that time was admitting a lot of graduate students, a sizable fraction of my class and the classes before and after, and they were very talented, every one of them. I think there was a lot of inherent misogyny in science. There is now, but then, it was much more so. My guess is that those women—all the faculty were men. There were no women in the faculty in sight. I would say maybe one third of our students may have been women at the time, something like that, which at that time was a pretty high number. The classes before and after mine—I was there at a very heady time for the Seismo Lab. It was an extremely successful period of time scientifically. The folks that were my fellow graduate students, a lot of them went on to prestigious faculty positions elsewhere, but nearly all the ones I can think of who went on to prestigious faculty positions were men. The women tended to end up at national laboratories or soft money positions or oil industry.

I want to be really careful what I say here, because I'm kind of racking my brain saying, "Are there—?" I can't even think—there probably are some exceptions, but I can't think of any right now who went on to kind of R1 faculty positions. There must be some. I wouldn't be surprised if I'm missing it. But clearly the career paths ended up being different. I think that women in those times, you did not have, for example, any kind of provisions for family leave, so that women who thought about having children did not see being an assistant professor as something that was going to be very attractive. Working at a national laboratory or making more money in the oil industry, working for NASA, et cetera, I think was more attractive. I also think, in retrospect, that they probably were not encouraged to think about doing that.

I noticed you interviewed Thorne Lay. Thorne was a great student, a fantastic seismologist, went to Michigan, now has been at Santa Cruz, had a great career. People like Steve Grand. Gene Humphreys at Oregon, who is a dear friend of mine. I can think of a number—now, it may not even be that a majority of the men took faculty positions, but many of them took prominent faculty positions, myself included, in time. I went to Oregon first, and then I went to Berkeley. It has always struck me that I wish I could—having worked in diversity a lot for the last couple decades, I wish I could go back and kind of more accurately reconstruct what the dynamic must have been. Probably the most interesting thing would be to talk to some of those women colleagues and say, "Hey, what was that like? How did you feel there? How did people talk to you? What were you encouraged to do?"

ZIERLER: It was the foundational generation, so everybody was sort of figuring it out in real time.

RICHARDS: Yeah, and I can say that one of the things that I would say about Caltech in general, but the Seismo Lab in particular at that time—it was a very monastic existence. You were surrounded by all the help and resources you could ask for, brilliant people. You had support. Students would be there all hours of the night. There was a sense of not only were you kind of expected to work that hard, but it was fun. I'd say that at Caltech, you think about the quad out there and the way it's constructed and so forth—it's kind of a monastic place, or at least it was, yet I can imagine that that kind of monastic existence literally is built for men. Like I said, I've thought a lot about the fact that we had all these really talented young women graduate students, but their career paths were different. I say that cautiously. I'm cautious about what you might report about what I'm saying, because I expect there may be some exceptions that I'm overlooking. I don't mean to diminish their careers at all. There's nothing wrong with working for NASA, national labs, oil industry, et cetera. But it's conspicuous to me that the folks filling the faculty positions coming out of the Seismo Lab, at that very influential time, I think were nearly all men.

ZIERLER: To fast-forward, where you would have had more of a perspective on this, either at Oregon, Berkeley, UW—has that changed? Have things gotten better?

RICHARDS: Yeah, we're getting a lot better, in time. I would say that the incremental progress we've made, especially in the last couple decades, with women faculty at leading research universities, has been fairly steady, to the point where I would say there's still a lot of problems, and women would have a better perspective, but it is moving toward being self-sustaining. You can't say that about underrepresented minorities yet. The numbers—I publish on this [laughs]. For example, we still only have about 10% to 12% underrepresented minority PhD students in the mathematical, physical, and computer sciences. It's different in biological sciences, but I've worked in the former. It's even worse when you look at postdocs. This is something I've been really focused on and done a lot of work on in the last decade, mainly at Berkeley. We only have like 3% or 4% underrepresented postdocs, and postdocs are where we hire most of the faculty. In fact, we hire underrepresented faculty at a higher rate than postdocs are available, probably because we're trying harder and we pay more attention. The postdocs are this kind of unattended-to source of labor. I've been trying to get NSF to pay more attention to diversity among the postdoc ranks, because it feeds the scientific leadership ranks, not just professorial ranks.

ZIERLER: That's the crucial pipeline you're referring to.

RICHARDS: It is. The fraction of underrepresented minority postdocs is smaller than the fraction of faculty, interestingly. The fraction of faculty is—it depends on who you count and where—but around 5% or 6% nationally, but the postdocs are like 3% or 4%.

ZIERLER: To go back to the Seismo Lab, to close out your time there, besides Brad, who else was on your thesis committee?

RICHARDS: [laughs] I've got to remember—who was on my thesis committee? Dave Stevenson was. I think Tom Ahrens probably was. God, I'm really embarrassed to not be able to know for sure. Probably Barclay Kamb.

ZIERLER: Oh, wow.

RICHARDS: Barclay, you've probably heard of.

ZIERLER: Sure.

RICHARDS: I spent two summers living on a glacier with Barclay. I probably was a real torment to Brad Hager, because I spent so much of my time doing other stuff. We were required to do three research propositions, and I got interested early on, and I wanted adventures, so I was doing reflection seismology off of a glacier in Alaska. That's how I met Hewitt Dix, because he taught me about how to do reflection work. I also performed in two different musicals at Caltech. Let's see, we did South Pacific and Fiddler on the Roof. I was the leading male in both of those, because I came from a singing, music background. Dick Feynman was in South Pacific; he played the bongo drummer, which was quite a—he had just had his cancer surgery, and he had this giant scar across his abdomen, and he made a big point of having his shirt off on stage so everybody could see his scar.

ZIERLER: [laughs]

RICHARDS: He was such a character. Anyway, that's a distraction, too. What were you asking? Oh, my thesis committee. I believe it was Brad, Tom Ahrens, Barclay Kamp, and Dave Stevenson. Those are the names that come to mind. I should know that. You can go look up my thesis if you want. It's all there.

ZIERLER: Was it the kind of defense where you knew more than everyone else in the room?

RICHARDS: Dave Stevenson wouldn't say so. [laughs] But yeah, I would say that—Brad and I, he was a coauthor on all the work that I published for my thesis, so he understood very well what I was doing. I did stuff that he wouldn't have done otherwise, but I would say that he—I did have a sense of accomplisment…when I did my defense, there wasn't any doubt that I was going to pass. Nobody had any qualms about any of the work. It was all basically either ready for or submitted for publication, or published. It was kind of a matter of when I wanted to finish, and I got a postdoc in Australia, and then I left.

ZIERLER: Was ANU really attractive to you?

RICHARDS: Well, yeah. Again, I had some good fortune, which was that I was almost simultaneously offered a faculty position at University of Oregon and a postdoc at ANU. The ANU postdoc would have been a two- or three-year appointment, but I didn't want to turn down the faculty position at Oregon, because I liked this old hippie town. Eugene appealed to me. It was in the mountains and so forth. I talked the people at Oregon into letting me have a year to go to ANU, which is what I did. I didn't actually have quite a year, but it worked out really well. I went there, I believe, in March. Literally a week after I finished and turned in my thesis, I didn't stick around for my graduation, I went to Canberra. I flew to Australia. I was there pretty much for the better part of nine months. Then I came back to Eugene, and in January of 1987, I started on the faculty there.

The Australian experience for my postdoc worked out super well. I had a great advisor, Jeff Davies, there, and a couple other people—Ross Griffiths and Brian Kennett—that I worked with. My science work there worked out really well. I just didn't have enough time to finish it, so they supported me to come back the following two summers and work there, in Australia, and basically be supported to do my research. That was enormously beneficial to getting grants funded at NSF eventually and kind of getting kick-started. That postdoc was more than just a nine-month stint; altogether I probably spent about a year and a half there. I got to have my cake and eat it, too. I got the faculty position at Oregon.

ZIERLER: What aspects of the postdoc were extensions of your thesis research and what was new?

RICHARDS: Most of it was new. Fortunately, I had prepared nearly all of my thesis work for publication before I left, so when I went to Australia, I was able to do some really new stuff that turned out to be very fruitful, and to work with people who were doing—I worked with a seismologist named Brian Kennett. I worked with an experimental fluid mechanics person named Ross Griffiths. I just learned a lot. ANU was a very good place, but it was very different from the Caltech environment.

ZIERLER: Did Oregon have a strong program in geophysics?

RICHARDS: They had an okay program in geophysics.

ZIERLER: Was your hire part of a growth effort?

RICHARDS: Yeah, they hired two of us at the same time. A fellow who was a close friend of mine at Caltech, and one class ahead—they actually hired both of us in the same search, because they liked us both. His name is Gene Humphreys. In doing this historical project, you ought to talk to Gene. He's a fascinating person. He just retired from Oregon, so he stayed there in his career. Really colorful character and was one of the pioneers of seismic tomography and worked with Rob Clayton. Gene and I went to Oregon together. There was one other person who had been chair of the department who was a high-pressure mineral physicist named Harve Waff, who had talked the department into hiring another geophysicist and they ended up hiring two of us. Since then, they've gotten a lot better in geophysics. I left, but they've hired several more people that have turned out to be really good.

ZIERLER: To bring our conversation right back up to the present, did you have administrative responsibilities at Oregon, or did that path really start for you at Berkeley?

RICHARDS: No, I was just an assistant professor at Oregon. I think I got a good bit of attention my first couple years there, because I wrote a couple proposals, oddly, that got people's attention, to do some new work. I got recruited to Berkeley. In fact, Caltech was talking to me about—because Brad Hager had just left, and they were talking to me about coming back to Caltech, but I didn't really want to live in Southern California, so I ended up going to Berkeley. I had no administrative experience. I was at Berkeley for a few years, and then I got recruited to go back up northwest to the University of Washington. I actually spent a year and a quarter at University of Washington. That's a whole long story having to do with getting married and everything else, but I came back to Berkeley—I got brought back to Berkeley with a good promotion.

I also came back to Berkeley thinking that they really needed to start something in atmospheric science, which was just completely lacking at Berkeley. They didn't do any oceanography. They didn't do any atmospheric science to speak of. It was a real hole in the institution, from what I could tell. You're not going to create a new program in oceanography, because the oceanography schools like Scripps and Woods Hole are dominant, and you can't push them aside. But atmospheric science was a real opportunity. I started an initiative as a faculty member to establish an atmospheric science program, which got real traction. We went out and hired five people across four different departments. For that reason, I got made department chair in 1997, after I had been back three years.

Then my route to becoming a real administrator was even more odd, because in 1999, after I had been chair for two years, my wife was offered a really elite medical residency. She had just finished medical school at UCSF. She did an MD-PhD at UCSF Berkeley. She had also stayed home for three years with our twins, who were just born, and it was time for her to reestablish her career. I needed to be able to go to Johns Hopkins with her for her residency for a couple years, and they asked me to be an interim dean for one year, at Berkeley, at the same time. I made a deal with the provost. I said, "Okay, I will be interim dean for a year, but after that, I've got to have two years off so I can go to Baltimore." That's how I became an interim dean. It was kind of a deal with the devil, but it worked out. Then while I was in Baltimore, the dean who had gone on sabbatical while I was interim retired, and then they brought me back as the dean. They recruited me to come back as dean. It was all, again, kind of a giant accident, in a way, but fortuitous, for the most part.

ZIERLER: Kind of a theme with your career, going all the way back to undergrad.

RICHARDS: Yeah. Even my starting off in engineering at University of Texas was pretty serendipitous. It's not without—I would say that there's a balance, there. I knew I wanted to do something as an undergraduate that was not music. I basically wanted to learn how things worked. Engineering appealed to me. When I switched to geophysics at Caltech, it was because I wanted to be outdoors. When I ended up going into university administration, it was more family-involved, but it was something I felt like—not all academics are of the right mindset to be very good in administration. It's something that, after I had been department chair, I realized I kind of knew how to work with people that way. But that opportunity presented itself, and the rest is history.

Open Doors and Openness at Caltech

ZIERLER: On that note, for the last part of our talk, I'd like to ask a few retrospective questions, and then we'll end looking to the future. On the science side at Caltech, what has stayed with you, in terms of the approach to the research, understanding the data, when to go out in the field? What has stayed with you over the course of your career that you learned at Caltech?

RICHARDS: I guess what has stuck with me is something I hinted at before, which is that the Seismo Lab at that time was a place where—I had a research advisor, but every faculty member there had their door open to me, if I had interests or questions to pursue. There was a certain—I described it as a bit of a monastic existence, but also there was a community there, that was incredibly supportive and patient with students and their interests. There was not a sense of, "You work for Professor X; you need to grind out this thesis and get on with it." There was a sense of adventure and exploration.

The thing I would add to that is that it was a unique collection of intellectual skills and personalities. I can tell you the people who were on the faculty there when I was there. It was Hiroo Kanamori, Don Helmberger, Dave Harkrider, Don Anderson, Rob Clayton, Brad Hager. Clarence Allen, and people in planetary science like Dave Stevenson and Peter Goldreich, who happened to be interested in my work, for reasons that I won't go into. There was a sense of each of these were unique personalities, had unique views on science, often not even entirely compatible scientifically, but they got along and they respected each other. There was no stigma to my spending time learning about planetary dynamics from Dave Stevenson even though I was focused on the Earth. There was no stigma with the fact that I spent two summers learning about glaciology with Barclay Kamb in Alaska. All of those things, all of those different experiences added up to kind of making me my own scientist, whatever my own unique qualities are. I would say the fact that there was that variety of opportunity, and that freedom to explore, made me a much better scientist. If I had just had my nose to the grindstone, as is often true in PhD programs, I probably would have had a good thesis with Brad Hager, but my ability to be creative and adventuresome after that would have been much more limited.

ZIERLER: On the social side, in light of what you've gone on to do in academic leadership, in the way that Caltech invested in you and had an open door policy, and there was coffee, and there was that spirit of openness, what are some of the takeaways there in terms of establishing a healthy academic community?

RICHARDS: I don't think there's a formula. There are lots of different ones. They tend to come and go in time. I cannot speak, for example, about whether the Seismo Lab is still that way. It may or may not be. But I think the overall message is, "Pay attention to the fact that we're human beings." That that social environment matters a lot. In fact, it may be the most essential thing, in a way. As scientists and as academics, we tend to forget that. We tend to think that it's all about talent and hard work and money and support, et cetera. I don't know what you've found in your historical research, but I do believe that time of the early to mid 1980s at the Seismo Lab was an extraordinarily productive and creative time. I think there may have been some times after that when it wasn't quite that good, but I wasn't there. I don't know what you're finding, what you're hearing from other people.

ZIERLER: A range of responses; yours is right in the middle. Last question, looking to the future: If and when you do get that opportunity to step down as provost and you want to go back to research full-time, what would you work on?

RICHARDS: Oh, I already know that; I'm doing it. [laughs] There are three major areas of research that I'm pursuing right now. They'll come and go, bubble up in time. I'm always going to be interested in this question of large-scale volcanism associated with mantle plumes and the potential relation to mass extinction. It's just an endlessly fascinating problem with all sorts of implications. My skill set is pretty well suited to working on that type of a problem. The other thing is I hope to god that I can continue to work in the Galapagos, because that's basically the relationship between geology and evolution. The history development underlying physics, geophysics of how those islands have developed, and how they're related to the evolutionary pathways in the Galapagos, that goes right back to Darwin. You know, Darwin was a geologist; he was not a biologist. His insights from his three weeks he spent there on the Beagle were primarily possible because he understood that those islands were young volcanos and that those critters had come from somewhere else, that they weren't put there by god. So, the Galapagos. The third thing is there's a general area of large-scale mantle dynamics, relationship between plate tectonics and the kind of lubricating effect of water, in the upper mantle that allows plate tectonics to occur. I'll probably never get tired of that problem. I generally work with other people who do the actual numerical modeling, but that goes all the way back to my PhD thesis.

ZIERLER: Mark, this has been a great conversation. I'm so glad we were able to do this. Thank you so much.

[END]