Professor of Geosciences, Emeritus, Princeton University
By David Zierler, Director of the Caltech Heritage Project
April 11, 2022
DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It's Monday, April 11, 2022. I am delighted to be here with Professor Robert Phinney. Bob, it's great to be with you. Thank you for joining me today. To start, would you tell me your title and affiliations?
ROBERT PHINNEY: I'm a Professor, Emeritus, at Princeton University in the Geosciences Department.
ZIERLER: What year did you go emeritus?
PHINNEY: That's a good question. At least ten years ago.
ZIERLER: Have you remained active at all? Do you stay on top of the literature?
PHINNEY: I go to seminars at the department, my pre-emeritus department. Of course, one reason one retires is so that the chairman can make new offers to young people to fill out the faculty with 30-year-olds. That was some time ago now. I go in for seminars.
ZIERLER: Tell me about some of the major areas of research over the course of your career. What have you worked on?
PHINNEY: I count myself as a seismologist. The Seismo Lab at Caltech was the place. But unlike a lot of my colleagues, I get bored after about three years, and I switch to some interesting new angle. Since I got involved in the 70s and 80s with a project that required serious funding from the National Science Foundation to do reflection seismology, that is, to use big vibrator machines to do reflection imaging of the continental crust, down to the bottom of the crust, which is anywhere from 20 to 40 kilometers down. This was a big deal at the time. I worked on that, then I got really involved in an outfit called IRIS, Incorporated Research Institutions for Seismology. IRIS got moving because there were now too many eager young seismologists out there who didn't have equipment to record seismic signals. You had to pay for the equipment, which meant you had to go to the NSF, and you had to get a grant, and they would give you three seismometers. In our business, it turned out that it was terribly important to have globally 100 or 120 seismometers. This was 10, 15 years ago.
And portable seismometers, the kind that you put in a pickup truck and deploy when you're putting out artificial sources or recording small earthquakes, you needed a couple hundred of these instruments. The whole community pulled together a scheme to incorporate an organization, which would own all this equipment, and then have rituals for deploying it in the hands of people who had written proposals and gotten funded to use this equipment. The international side of it, global seismology, involved a lot of countries. At the same time this was going on, this IRIS, multiple seismometer game, a whole community of people was involved in doing geodesy, which involved determining the deformation of the crust using different types of instruments, also instrumental. And it also was a group of institutions that joined. They were more or less focused on Boulder, Colorado at the big laboratory there. Finally, this year, just now, NSF has said, "Well, we have these successful programs, but we've got to go ahead. We can't just duplicate the money we gave you last time. You've got to write up new rituals and rationales and expand. And you've got to get together."
The IRIS group we were involved with and the UNAVCO group that was doing the deformation of the crust had to get together and form one group involving all of the institutions. Typical bureaucratic solution to a problem, but the problem was that there was a lot of really good stuff to be done. They had just been through a five-year period of restructuring the whole national and international organization of these collaborations. There's just one organization, but they have all the best technology available as of now. Of course, I haven't had any to the do with that. I've been out for about 12 years, retired. But they're going ahead gangbusters, having workshops, giving the NSF a chance to boast about all this great new technology that's being deployed. But this all bows down from the Caltech Seismo Lab. That was the beginning of a whole era.
In the late 50s, the Office of Naval Research and the Air Force were involved in funding seismology at sea, and the institutions involved were Columbia University, Scripps Institute of Oceanography, La Jolla, and Caltech. Shortly thereafter, I think Berkeley got heavily involved. There were just four institutions that were active. Now, there are probably 150 institutions, plus other countries. I'll bet if you gave them the chance, the Ukrainians would join. It's that kind of thing, part of a thriving institutional setting for doing science. But it was just Caltech, Scripps, Lamont, Woods Hole Oceanographic. That was it. When I came to the Seismo Lab, it was in 1959, and I was a graduate student at the Seismo Lab. My advisor was Frank Press. The cast of characters at that time, I was just looking at one of these imaging programs that enables me to read license plates in a strange city. I discovered where the Caltech Seismo Lab was when I came. It was North San Rafael Boulevard in Eagle Rock. It's on the other side of the Rose Bowl up in the hills.
The homes up there are still pretty fancy, but of course, there are no Seismo Labs there anymore. They're just really fancy homes you put in the hills near Pasadena. I remember, we had two labs at this campus location, this site in the residential area on San Rafael Boulevard. One was down the hill, and it was where the equipment was located. In those days, it was just one room with what they call a concrete pier, where we put the instruments. In 1959, if there was an earthquake in Southern California, it would be reported to the news media by Caltech, and it would come from one instrument located in a concrete pier down in the hill in this residential area. Then, there was a facility, a bunch of desks, and there were two or three employees who read those seismograms. A seismogram in those days was a piece of paper this wide, this long that was wrapped around a drum. Then, the drum rotated so that every so many hours, the pen would come back, repeat where it was, and shift along. You'd have a specialized piece of paper. The public got used to having a seismogram consist of a piece of paper that was this high, this wide, wrapped around a drum. The wiggly lines on there were the seismograms.
You could get 24 hours, 24 rotations. This is an ancient technology. Nowadays, of course, everything's digital. Nowadays, when you have any object that has got seismometers or people who do seismology, or study earthquakes, study local earthquakes in some place, study international earthquakes, they will have a lobby with a place with a fake copy of this recording device so that the public can come in and look at it, even though it's digital. There are hundreds of them around the world now. The Caltech Seismo Lab had a building down there in the woods. There were orange and lemon trees. Being an eastern boy, I was amazed that these Southern California citrus trees had no flavor at all because they weren't produced by corporate research, they were just what happened to be growing in the backyard of the lab. Then, about 100 yards away, up the hill, was the lab in which all of the academic guys and graduate students hung out. It was an old-fashioned building. They don't build buildings like this anymore.
If you came in the door, you looked up there, there was an office that kind of came out, and there was Beno Gutenberg sitting there. And he would come out. Then, down in the basement with the other labs was Charles Richter of the Richter scale. Frank Press was in a director's office, but it was in another part of the building. They had Frank Press, who was the young hot shot straight out of the East Coast after his rapid rise out there working with Maurice Ewing. Frank Press was the director of the Seismo Lab. But Beno Gutenberg was the senior eminence. Of course, we hardly knew him at all. And Charles Richter was in the basement, helping his buddies make pics on these film recordings. Then, Hugo Benioff was there. I have no idea what his history is. But we were all in this building, and it was a sprawling wealthy person's mansion in the wealthy suburbs of Pasadena. Of course, as soon as I got there, the same year I arrived, a whole bunch of other students arrived who had all heard about Frank Press and wanted to go to Pasadena to be at the Seismo Lab.
There was this explosion of bodies into this building in the woods. This was all people who ended up becoming professors somewhere else later. There was a guy named Jack Healy, Shelton Alexander, Don Anderson, David Harkrider, Charles Archambeau, Stewart Smith, Ken Watson. Then, as a toss-in, there was also Jim Hayes, who was not at the Seismo Lab, but he was a beginning graduate student in geology, and he had an office assigned to him on the Caltech campus. All of us had offices assigned, a desk, a wastebasket, a place to plug something in, in Ames or Mudd Hall, which were on the Caltech campus. We Seismo Lab denizens spent our time in the countryside, out in the woods, hanging out together. It was some decades later that there was a new building put on the Caltech campus, and the Seismo Lab moved into that.
ZIERLER: What year did you arrive at the Seismo Lab?
ZIERLER: What were some of the big ideas at the Seismo Lab at this point? What were some of the debates?
PHINNEY: I hate to tell you, but we had all come from places like Scripps, and Woods Hole, and Columbia, who were headed by genius-type people. Maurice Ewing was an autocrat of the first magnitude. He had a campus out on the Hudson River right near the state line between New York and New Jersey. And he had a ship, the Vema, a four-masted schooner, and he went all over the world with his graduate students, doing whatever. The whole world ocean was unknown. This was a period when plate tectonics hadn't been discovered yet, and all of the observations which led to the plate tectonics revolution were done by graduate students going to sea because you needed to be at sea in order to get the real image of what the gravitational and magnetic anomalies were like. It's a case where if you don't have the money, you've got to use your brains a little bit. A lot of things happened in these other institutions. Some really smart people started thinking about big issues.
A guy named Jason Morgan, who was hired when I got to Princeton, became a faculty member, and he was one of the originators of plate tectonics. Those of us who were at Caltech at the Seismo Lab realized that the geologists ran a tight ship. You had to go to a place called Tick Canyon about halfway to Palmdale in the scrubby mountainsides in the ranges. The geologists at Caltech at that time were very insistent that they knew how to do geology better than all of us crazy seismologists from the East Coast. As beginning graduate students, we all had to take a field course, fill a notebook full of notes, use compasses, make maps, do all of the professional skill things that field geologists are supposed to be able to do. They were so proud of it that they missed out on plate tectonics, where the discoveries were made. It was a great experience at the Seismo Lab because we had these young colleagues, all people our age and a little bit one way or the other, a select group of people, and we all went on and started working at Penn State, or Berkeley, or Princeton, or Harvard, or Woods Hole, USC, all over the place. And that was when things exploded in terms of plate tectonics.
ZIERLER: What was it about that moment that caused this revolution in the field?
PHINNEY: It was the availability of data. In 1947, 1948, what did you have? A guy named George Marshall, the Secretary of State. He developed the Marshall Plan and went crazy with all of the aid to Europe that had been clobbered by the War. It was a period of two or three years after World War II when all of the nastiness settled down, and then we got the Cold War. Just like we're seeing in my opinion right now with Putin, the bad guy in the Kremlin causes a lot of trouble, but he also causes everybody to get their act together. That happened. And in 1948, '49, '50, there were missiles, submarines, nuclear weapons. All these ships were suddenly running all over the world's oceans. It was graduate students who got to look at the data that came from these ships. Back then, every type of equipment you had, magnetometers, seismometers, oceanographic monitors, if you were an oceanographer, you would go out with bottles and collect samples of seawater. It was data-driven. The data was there because there was an international Cold War popping off and the Korean War. Money was plentiful, and ships started running all over the ocean. It was definitely the data. It's really bizarre to keep track of this fiasco in Ukraine because no matter how threatening the bad guys are, it causes all the people you know to say, "Wait, what can we do?" It wakes up everybody of all ages to do science.
ZIERLER: Who was the leader of the Seismo Lab when you were there?
PHINNEY: Frank Press was the director.
ZIERLER: What was Frank like as a person?
PHINNEY: Frank was very buttoned-up. But he was loyal. Everybody admired him because he was so smart. He'd gone to City College of New York, then he did his graduate work at Columbia under Maurice Ewing. He was Maurice Ewing's big super-genius achiever. He was a buttoned-up guy, but he was consistent and loyal, and he would always have time to talk to you. And of course, he had a wife, Billie, who was bright-eyed and bushy-tailed. Very, very warm person. He was the guy. One other thing about being at the Seismo Lab, I would say at least two or three times a week, we'd get in our cars and drive across Pasadena to the Caltech campus because we had a seminar to go to. There was a thing called Geology Club, and the chairman of the geosciences department was a geologist, Bob Sharp, in a lecture hall in either Arms or Mudd, with Gerry Wasserburg and all of these hard-nosed field geologists sitting in the front row. We'd go back and forth, back and forth on Del Mar Boulevard, parking over at a parking garage that I think is still there on Wilson Boulevard. I was the first to get my PhD out of that gang, and that was mainly because I had done my undergraduate work at MIT. Cecil Green was very important, he was the founder of Texas Instruments and GSI, Geophysical Services Incorporated.
He was a Texas guy. But he was the first research staff member in Texas, which is where exploration for oil was going on. He was the first to discover what you could do with seismology. My chairman at MIT, when I was an undergraduate, I went into his office, and I said, "Everybody in the freshman physics lecture is obnoxiously tight-assed." They all wanted to build nuclear bombs or something. I said, "I want someplace where they do geology or interesting stuff instead of just trying to become important members of the "We Built the Atomic Bomb" generation. This was 1950, so the atomic bomb was a big deal. If you were a physicist, you had status in the world, and you knew it. I went in as a freshman and said, "These guys can sit in the front row and try to impress their lecturer with how smart they are, but I just want to know what's interesting." He said, "You want to go over to the geology department." It turns out the geology department chairman was a guy named Shrock, who had written books about fossils and sedimentary rocks. But he was a smartie. He discovered Cecil Green down there in Dallas and said, "I've got something for you."
Everybody who was not in our group at the Seismo Lab, some people who were a little older, ended up being affiliated with things Cecil Green was doing in Dallas as young scientists working for him. There's a building called the Green Building at MIT, 23 stories high. When I was an undergraduate at MIT, we were in an older building, and we kept track of how much money was in Texas Instruments' stock by keeping a big chart on the wall showing how many stories it'd gotten in the Green Building. [Laugh] This was Cecil Green. When Cecil was much older, he invited about 100 people who had been part of his evolution of geophysics to the beach at the tip of Baja, California. We've got this picture of all of us, all the names we know. Don Anderson, Charles Archambeau, Shelton Alexander. Everybody's in this picture. And people who were post-docs at MIT in the 50s, before the Green Building existed.
ZIERLER: What were you interested in? What was your focus of research at the Seismo Lab?
PHINNEY: I was doing all theory. Ewing and Press wrote papers when Ewing was the big noise at Columbia and Press was his graduate student, and what they were discovering was a thing called surface waves. Surface waves are a mode of deformation, where the whole stack of layers oscillates in synchronous form. When you have a big earthquake, it produces P-waves and S-waves, but it also produces surface waves, which are slower. These involved some nice applied mathematics in the world of Fourier transforms, things like that. I got interested in the theory side of it. My PhD thesis was how you could set up the applied mathematics of constructions to figure out not just how the surface waves behaved, but the P-waves and S-waves. The P-waves and S-waves were just blips until Ewing and Press came along and showed that these were things that could be demonstrated using applied mathematical tools. That's what I was working on, applied math. And of course, I kept changing what I liked to do about every five years because it was more interesting.
ZIERLER: You saw the Seismo Lab when it was off campus, when it was in the mansion. Tell me what that was like.
PHINNEY: I'd forgotten all the street names we had to navigate to get to Caltech from the Seismo Lab. Of course, they're loaded today with freeways that weren't there at the time. The Colorado Freeway, the Ventura Freeway, they all go through Eagle Rock at San Rafael Drive. But you could just go there and look at these elegant houses with red Mediterranean tile surfaces. It was a different era.
ZIERLER: Did it feel removed from campus?
PHINNEY: Yeah, it did. But there were enough of us out there that it didn't matter. It was only maybe ten years later that Caltech put in the new building on Wilson Street between Arms and Mudd. The new Seismo Lab was in that building. Everybody seemed to agree it was about time to move to campus. Don Anderson was the next one to graduate with a PhD after me. Don was a very gregarious, intelligent guy. He had been in the Air Force. He was several years older than me and had spent time in Greenland doing seismology in 1948 or so. Don and I, after we had gotten our PhDs, started hunting around for a place to get the money together to start a research lab. We tried to start a Seismo Lab at MIT. They weren't buying it. "You've got to be on campus with everybody else." The person who blew us off, a snot-nosed young scientist. We wanted to have a laboratory facility out in the countryside. The guy we talked to was the provost at MIT, Charles Townes. He said, "Nope." Anderson and I went on separately, but that's OK. You learn something, and you move on.
ZIERLER: What was your thesis research on?
PHINNEY: It was this theory, an applied math thing. It was about faults, branch points. It was all important because in 1963, we didn't have the equipment we had in 1993. The equipment in 1993 was what I worked on a lot with this IRIS organization, which was putting hundreds of instruments around the world. Whatever branch of science you're in, you're going to have limitations as to how you can carry forward because you can't get the observing equipment to do the science. The science depends so much on observation. At Princeton, we were trying to recruit some possible graduate students, so we got permission from the physics department to look at some application folders from young people who were applying to do graduate work in the physics department at Princeton. They all had to say whether they wanted to be theoreticians or observationalists. Observationalists were just grudge-y people who worked in the machine shop. But theoreticians, that was the best thing since sliced bread. These were the people who built the hydrogen bomb. All these youngsters coming to do graduate work at Princeton in physics wanted to be theoreticians. About one in ten would want to be an observationalist. Of course, most of them didn't get into Princeton to theoreticians because all the good theoreticians were already on the faculty at Princeton. Phil Anderson was a Nobel Prize-winner at Princeton and Bell Labs, and he kind of pioneered making observational science respectable.
ZIERLER: You said you liked to switch up your field every few years. After graduate school, what research did you take on?
PHINNEY: A bunch of things. I used to go over to a company called Teledyne in Alexandria, Virginia, consult with them because they had seismic data acquired with big fancy tape recording equipment, and it was part of the Cold War, so it was a question of what was available. Of course, you would put instruments near Poland or someplace like that. That was not very satisfactory, actually, because the observation equipment still wasn't good enough. And it was only when I got involved with this IRIS organization, about '85, that they really got moving. Then, everybody in the community who wanted lots more seismometers was too busy trying to write proposals. I was the only one left. My job was to work on the total package. Then, I spent another ten years involved with this reflection seismology, which is the way the oil companies would do it. They would put vibrators on the ground and cross-correlate the vibrator outputs to get the reflection signals from layers down below.
We were involved in an NSF-funded program that involved people at Cornell and people at Exxon who used vibrators, higher vibrators to try to make images of the deep continental crust. It was seismology, but it was a different technology, an opportunity to get something to happen. Then, way down the line, I had a research program that involved putting blocks of seismometers into the back country in the Sierra Nevada, down around Mount Whitney. That gave me a chance to get instruments deployed in remote sites. These were instruments we had developed through the IRIS program. And that was such fun that I got Princeton University to fund a program in which they called them freshman seminars. We started them. This was about the beginning of freshman seminars anywhere in the world. We took three geologists out to Mammoth Lakes, California and went to a series of field sites on volcanic rocks, big faults, just impressive stuff. These snot-nosed kids from the East Coast had never seen anything like this. This was not seismology, this was just the world, what there is to see, if you look for it. And we did that for about ten years.
ZIERLER: What were some of the findings from that work?
PHINNEY: The findings were not scientific, they were educational findings. How to work with young people. And this is, of course, something everybody should know before they begin a teaching career, but it takes a while before you figure it out. There was a woman who was a freshman in our freshman seminar when we went to Mammoth Lakes. We would take them up this long slope overlooking a canyon, and I got a picture of her. And they spent a week with us during fall break. She turned out to play the clarinet, so when I retired, we got her to do a Brahms clarinet sonata along with a couple of other things. I said, "Where do you want to go to graduate school?" She said, "I want to work for a company for a little while and see what it's like to work for a company."
She went to work for Western Geophysical, which was working at sea with big, big ships. The technology then involved towing great streamers full of what they called air drives, which were explosive air shots at the end of a hose that's in the water. They paid well, and she went to work for them. I looked at her Facebook picture about two years later, and there was as picture of this woman with a bridal outfit on. Her husband was another young scientist on the ship, a man from Argentina. They settled in Ushuaia, the southernmost city in the world. They're down south, pretty nearly on the Magellan Strait. Ushuaia is a small, pleasant city that's got a lot of shipping traffic going through it and a lot of boat cruises down to the Antarctic region. She and her husband formed a company. He can build sailboats. They were running these cruises to Antarctica from Ushuaia in Southern Argentina. That's what happens when you have freshmen going into your geology course.
ZIERLER: What did you work on next?
PHINNEY: My wife runs an organic farm here, and that's enough.
ZIERLER: I'd like to ask you some reflective questions about the Seismo Lab. First of all, did you feel connected going all the way back to the origins of the lab? Did you feel that history when you were there?
ZIERLER: In what ways?
PHINNEY: Well, they were all there. Gutenberg, Richter.
ZIERLER: Did you interact with Gutenberg at all?
PHINNEY: He had retired. And we spent a lot of our time driving back and forth to the Caltech campus. Gutenberg was like any of us retired people. "What's the hurry? We're not going anywhere."
ZIERLER: What about Richter? Did you get to know or work with him at all?
PHINNEY: Now and then. Actually, there was a whole epoch at Caltech, and I was not involved, when the Seismo Lab acquired people from the USGS. This was a whole piece of history I had no connection with. But this gave the Seismo Lab a lot of muscle.
ZIERLER: Did the Seismo Lab have instruments that were attractive to outside researchers who only had this access at the Seismo Lab and nowhere else?
PHINNEY: No, the innovative energy into instruments really came out of Scripps and Woods Hole because they were ship-based. People who are ship-based have to have complete technology infrastructure to do anything on a ship.
ZIERLER: What about the Seismo Lab as an intellectual center, gathering places for scholars to talk about cutting-edge developments in seismology? What are your memories?
PHINNEY: We were just graduate students, and we just talked. We developed a whole community of people doing difficult things. It wasn't until the IRIS organization got going in the 80s that people collaborated because they had to collaborate to generate a whole technology generation of instruments that everybody needed. This was a forced collaboration around the world. While I was at the Seismo Lab, it was just Frank Press, Don Anderson, Charles Archambeau, David Harkrider. The old guys.
ZIERLER: Was anybody talking about detecting earthquakes in those days? Was that even theoretically possible to discuss?
PHINNEY: The world's seismologists would frequently go places like France, Spain, Italy, and hang out and talk this kind of stuff. There were attempts to do prediction or identification. But our generation learned that if you are not efficient with your time, you're not going to get anywhere. It's got to be timely for whatever you're trying to do.
ZIERLER: Is that also true today? Is it the same issue?
PHINNEY: I don't know the science anymore because I've been out of it too long. But when I was going through, you recorded earthquakes, and there was the earthquake, the P-wave, the S-wave, the surface waves. Anything that was small, you could hardly do anything about it. It's been only in the last ten years, which is pretty recent, that internationally aggressive young scientists have figured out how to measure the noise, not the earthquake. And this is now a huge deal because if you've got enough instruments, and the instruments are sensitive enough, and you have telemetry so that you can have real-time access to the data, you can start looking for things that you couldn't look for before. That's way out of my league now.
ZIERLER: But even if you're out of the science, what are some of the remaining questions in the field, questions that might be as fresh as when you were a graduate student?
PHINNEY: Well, there are still some questions. People are still writing papers, and they're not getting answers yet. What is the mechanism, what happens when an earthquake is deep-focused? Let's say 600 kilometers deep. There are plenty of reasons why that's impossible. Plenty of reasons why, if you take a piece of the earth at 600 kilometers deep and deform it, there'll be no earthquakes at all. But you get earthquakes, so what's going on? People are still working on it. But every year, more insight comes. Nowadays, I'd say, if you're using seismology to image the interior of the earth, what resolving power are you going to go for? You always want more resolving power. You want to be able to see the details. The more you can see the details, the more you realize you didn't have any idea what was going on, it was different. That's where the field is moving, in the direction of upgrading the resolving power. That, of course, doesn't mean just the spatial resolution, but also the time variability.
ZIERLER: What have been some of the biggest surprises in seismology of your career?
PHINNEY: All of them. All of the discoveries are surprises. The surprise is that you understood a whole lot of things about the earth, about earthquakes, about geophysics, about planets. What's interesting is not what you can't learn, it's what you didn't expect to learn. The surprises are always the interesting ones. It can be anything. It's all got to do with the timeliness and the existence of a scientific community that communicates all the time. And by the way, big-time in our business is the sharing of data. That's something that was a critical aspect of our IRIS initiative in the 80s. We couldn't be having people compete to have more equipment than anybody else. It had to be that if you had seismic instruments recording, what's going on? It could be on Mars, could be on the moons of Jupiter, could be here. Right now, the big noise field is ice caps, Antarctica and Greenland. What's happening? There are micro-earthquakes occurring at the bottom of these ice sheets. No matter what you thought you were going to learn, there's some other surprise there, something you hadn't factored into your discussion. All the discussions you have are not logical creations.
ZIERLER: One last question. Given how small the field was way back when you were at the Seismo Lab, are you surprised at how big it's gotten? And what does it tell us about seismology that it's gotten so big?
PHINNEY: It's really hard to put your brain back into what you were thinking about in 1950. Everything was scaled down. It was a different scale of everything. But of course, I've enjoyed reading a number of important physics books in the field of chaos theory, things like that, which are just entertaining. All you know is that there's a lot of unexpected stuff, and there are smart people doing something with the unexpected stuff in some field. One of the things I noticed since I don't get into our department very often, I saw a department mug shot book. There was a young woman, and I met her at a reception last year, and what was she working on? She wants to know how ice sheets deform, and she's using seismology. I was like, "Are you a seismologist?" Sure, she's a seismologist, but she's also something else completely, a climatology specialist. And of course, our department is hiring people like that, who are doing things that nobody had any notion of.
ZIERLER: Well, Bob, it's been a real pleasure to spend this time with you. I'm so glad we were able to do this. Thank you so much.