May 2015 Virginia Tech Geosciences Commencement Address:

Welcome to the geological community

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Prof. Ross, members of the faculty, parents, friends, and graduates:

It's a pleasure and honor to have the opportunity to share your celebration today. It may seem strange to have an outsider, on his first visit to Virginia Tech, speak to you. However, in a way it makes sense. I'm here to welcome you - today's graduates - to the community of geologists across the country and around the world. When I say "geologists" I mean all the earth sciences - geology is just "earth science" in Greek.

Community is a word people throw around a lot, but in this case it really means something. You're joining a group of people who think about our planet - and other planets - in very sophisticated ways. They know more than most other people about the complicated interacting ways the earth system works. And just as importantly, they have the wisdom to be humble in the face of the complexities of nature. They recognize that the earth is very complicated, and there's a lot we don't know about how it works. We're smart, but the earth is smarter. This combination of knowledge and wisdom is what makes us special.

You've already figured out that geologists are a welcoming community - we like what we do, want to share it, and welcome new people. We love the influx of energy and new outlooks that people like you bring. I bet many you have already told friends how much you like geology and encouraged them to think about studying it. I'm sure you've talked about what you know when big natural events like the Nepal earthquake happened.

You'll find when you meet geologists, from very different parts of our science, or other countries and cultures, there's often a natural bond. You don't even have to meet them in person - you'll read a scientific paper or a blog - and say "that's a neat idea. He or she nailed it." There's a common set of knowledge and a common outlook. Sometimes you finally meet a person you've known only from their work, and often hit it off well. Despite living in different countries and speaking different languages, you've developed a very similar view of how the world works.

Some of you might have seen a picture of me in EOS last month sitting on the banks of the Isar River in Germany with a class I was teaching at the University of Munich. In Germany - like the US - the most damaging natural disasters are floods. Based on our discussions in class, I asked whether they thought Germany should have national insurance to cover everyone from natural disaster losses. The students in environmental humanities and law focused on society's obligation to citizens and favored insurance. However, the geoscience students - mostly German but an Italian and Canadian as well - said "no." They thought just like American students - society shouldn't subsidize people who chose to live in dangerous places. To geologists, nature is something we accept and learn to live with in sensible ways. As the adage says, civilization exists by geological consent.

An important part of our world view is that we think about our planet - and for that matter, other planets - as a whole. Political boundaries don't matter much. I thought of this in a discussion about the Iranian nuclear issue a few weeks ago with some people who didn't think much of that country's technical skills. I'm not sure why, since as near as I could tell, they'd never actually talked to anyone from Iran. They were very surprised when I said "I've met lots of very bright Iranians. I've got two - one male, one female - in class this quarter. They're very bright and nice young seismologists and a pleasure to talk to and work with." They're colleagues from another country, who seem to have nothing to do with weapons or politics.

Although we take our science seriously, we generally don't take ourselves too seriously. I suspect part of what helps us keep perspective is fieldwork. Even those of us who aren't primarily field people have had experiences that were so silly all you could do is laugh.

I still recall an incident 40 years ago at field camp. We had big orange metal map boards with stereo photos on one side and a map on the other, so you often walked around looking down at the board. One of my classmates came around a corner, looked up, and almost ran into a bear. He threw the board in the air, screamed, turned, and ran. Fortunately, the bear ran the other way. It took the instructors a lot of threats and cajoling to get him to go back and retrieve the map board.

Another friend was taking a beginning mapping class in the Mojave desert from Gene Shoemaker, a legendary field geologist who - among other things - mapped Meteor Crater and used the results to develop our models of how cratering works on the earth, moon, and other planets. Like most seismologists - myself included - my friend was much better at math than mapping. He just couldn't find the contact they were looking for until Gene said "if that contact was a rattlesnake, you'd be dead!"

Some of my silliest moments came in setting up GPS receivers. The receiver was connected to a metal antenna, shaped like a frisbee, mounted on a 4-foot high tripod. The antenna has to be set up exactly above a benchmark on the ground and be perfectly level. Getting this right is what connects all the fancy GPS satellites, atomic clocks, precise orbits, and computer processing to the earth. If the receiver's set up wrong, the data is worthless and the tectonic results will be wrong. Remember, we're trying to measure motions of a millimeter per year.

To make it work you sight through an optical system and move the antenna to the right place. Then you adjust three screws - one for each leg - to center a bubble in a circular level. Of course by the time you're level the antenna has moved off the mark, so you have to recenter, which makes the antenna no longer level, and so on over and over again... It feels like an intelligence test for monkeys, that you're failing. When you practice on a warm sunny day, it's frustrating but sort of fun. However, when the real survey comes, it's often cold, windy, and rainy, it seems like you'll never get it right and you're thinking that you're messing up a project that took years of planning. Of course, it somehow works out fine.

Another part of our culture is that we're very empirical. The earth is too complicated to have fundamental laws that predict what's going on, the way physics has. Instead, we take what we know and try to make sense of it. That means working with incomplete information. Our ideas about how the Blue Ridge mountains evolved are based on what we infer from the geological record of events long ago. Our ideas about what's in the Earth's core come from interpretations of seismic waves, lab experiments, and ideas about the chemistry of the early solar system. Our ideas are sensible given what we know, but might not be right.

An easy example is in building a nuclear power plant, we talk about the probability of a big earthquake happening nearby and how big it will be. We have no real way of knowing either. We have limited information about what happened in the past, and no useful way of saying what will happen in the future, beyond the obvious statement that anything that happened in the past can happen again. We can come up with numbers, but they don't mean much.

It's like the way in Shakespeare's Henry IV, Glendower says "I can call spirits from the vasty deep". Hotspur replies "Why, so can I, or so can any man; but will they come when you do call for them?" The earth doesn't have to do what we think it should, and often doesn't.

As a result, our ideas change. Often something new we find surprises us and forces us to change ideas that have been around for a long time and widely believed.

In fact, I'll tell you a secret. A lot of what you've been taught here at Virginia Tech is wrong. The problem is we don't know which parts. When I was in undergrad school we were taught that Venus had plate tectonics, just like earth. Once the first radar mission could map through the sulphuric acid clouds, we'd see ridges and trenches and the whole bit. The Magellan mission disproved that. When I was in graduate school we were told that in a few years seismology would predict earthquakes, which it still can't and may never be able to. We also learned that giant - magnitude 9 - earthquakes that produce the huge tsunamis could only happen where young lithosphere subducts fast, so places like Tohoku, Japan, or Indonesia couldn't have them. As you know, that proved wrong. I could go on with lots more examples.

This sounds great, but you may be wondering "do I really belong in this club?"

During the past few months, as you were finishing up your degree requirements, you may have felt like a bit of a fake. As you did problems and labs, worked on papers and theses, and studied for exams, you constantly hit things you didn't understand or didn't know. Why do some elements fit in a crystal lattice but not others? Why in some places is the Moho clear on a seismic section, but not on others? Why does Earth have plate tectonics but not Mars? Why do the same rocks behave differently in places a few miles apart?

I'm here to tell you that that's OK. Think about hiking up a mountain. I may have thought of this because when I saw Scott King last year, my colleagues and I took him to the highest beer garden in Germany, in the Bavarian Alps. Anyway, looking at the peak high above can be discouraging. The best thing is first to look down, to see how far you've come already. This makes you feel better - the reason you're tired is that you've come up a long way. Then you look sideways and admire what you can see as a result of your hard work. That feels good. Finally, you look up, and think of how great it will be to be on top.

Think about your education the same way. First, look back and think about what you know now that you didn't know four years ago. Geological time, rocks and minerals, earth structure, plate tectonics, rivers, glaciers, mountains, isotopes, etc, etc. All kinds of things you knew next to nothing about then seem so familiar now. The beginning classes that seemed so hard now look easy.

In four years things the faculty have carefully and successfully taught you things that took lots of really smart people hundreds of years to figure out: Newton, Gilbert, Hutton, Lyell, Darwin, Bowen, Wegener, Gutenberg, Richter, Jeffreys, Wilson and so on. If your education felt like trying to drink from a fire hose, that's why. Through your hard work, and your instructors', it worked. A few years ago you were students, now you're young geologists.

Next, look sideways. Because of all you've learned, you're already thinking much more deeply than most people about any of the many high-profile topics where geoscience is important. For example, you may have talked to some people who doubt that global warming is real or caused by humans, and others who are sure that things like bigger hurricanes result from global warming. You probably found yourself in the uncomfortable middle, taking a balanced thoughtful approach, trying to say what science can actually say and what we still don't know. You may have explained that - based on lots of data - we know the climate is warming, and we're almost certain it's because of human activity. At the same time, historical data show that the number and strength of hurricanes has changed over the years in ways that may have had little to do with global warming. Meteorologists are using computer models to see if hurricane strength will increase as the oceans warm, but different groups get different answers. You might have ended up saying that the two things we're most confident of is that the biggest problem is the increasing numbers of people living at the coast, and that rising sea level due to global warming will make hurricanes worse even if they don't get bigger. That probably wasn't what either side wanted to hear. So be it.

Finally, to see where you're going, look at your instructors or other older geologists. I wish I could tell you that by the time you get to our age, you'll have everything figured out. Unfortunately, although we've got more experience and know more, we older folks aren't really any different from you. There's lots we don't know about the earth, and a lot of what we think we know turns out to be wrong.

I personally get at least one huge surprise or embarrassment a year. Let me give just a few examples. I picked these because in each one it was insight from a graduate student that made the difference. Our old ideas are often like being trapped inside a paper bag, and all that's needed to escape is someone to just cut through it. Students are less used to accepting the paper bag, and thus can often see simple alternatives.

Part of my PhD thesis was studying earthquakes in the middle of the Indian Ocean, on a huge underwater linear mountain range at 90 degrees longitude, cleverly called the Ninetyeast ridge. Although this feature was called "aseismic", it turned out to be about as seismically active as the San Andreas fault. My colleague Emile Okal and I realized that the obvious explanation was that instead of India and Australia being on the same Indo-Australian plate, they were on two separate plates with the 90° Ridge being part of the boundary between them. The earthquakes proved that there was active plate motion. This was cool - two grad students get to redraw the maps in every geology book.

But, we had a problem. South of the equator, the earthquakes stop. We figured the boundary had to keep going south to meet the SE Indian spreading center, but there was no motion of it. We just couldn't make the geometry work.

A few years later, my colleague Richard Gordon and I, with a group of grad students, started a project called NUVEL to make a new global plate motion model. Each person took part of the world, reviewed existing data and compiled new data. Doug Wiens, a grad student who's now a professor at Washington University, did the Indian Ocean. He came to my office one day and showed me his new boundary geometry - an India-Australia boundary running south along the 90° Ridge, then west to the Central Indian Ridge. It was so simple an answer - running through a bunch of earthquakes I'd studied - that it had to be right. Doug said "I can't believe you missed that," and I replied "I can't believe I missed it." My wife analyzed the magnetic anomalies and showed that the model was right, so books now have separate Indian and Australian Plates.

Chuck DeMets, who's now a professor at Wisconsin, took the boundary between the Pacific and North American plates. That motion controls the tectonics of the western U.S. Most is taken up along the San Andreas Fault, and some causes extension in the Basin and Range as far east as Salt Lake City. We measure the total motion from magnetic anomalies in the Gulf of California, where the boundary is a spreading ridge. At the time, that motion was supposed to be 58 mm/year, which was more than the San Andreas and Basin and Range combined. The difference was called the "missing motion", and was supposed to be taken up on strike-slip faults off the coast of California. That's a great explanation because you can't measure strike-slip motion from marine seismic reflection data, so it couldn't be disproved.

Chuck remeasured the magnetic profiles, and they showed 48 mm/yr, not 58. For twenty years, the hundreds or thousands geologists interested in the western U.S. had repeated the old number, which became conventional wisdom. No one had gone back and just looked at the actual data. For all the talk about what caused the missing motion, no one realized that it was missing because it didn't exist.

I told Chuck it's a good thing we were in the midwest. A California student would have quit school and sold those profiles to Pacific Gas and Electric for a million dollars. There was a huge legal fight going on about a big earthquake hazard to coastal nuclear power plants. Without the missing motion, much of the hazard went away! We never got any money, but we did get a nice writeup in the New York Times.

Another surprise came when we did GPS in the New Madrid seismic zone around southern Missouri. There were big earthquakes there in 1811 and 1812, before the seismometer was invented. Based on historical accounts, these were claimed to be magnitude 8. Some people claimed they were the biggest in the US, or even the biggest in the world. This is pretty silly, but you'll hear it often, including in an "educational" video you may have seen called "Hidden Fury." Nobody asked "how could this be true?" Doesn't plate tectonics tell us that most deformation and the largest earthquakes happen on the boundaries between plates, not inside them?

The idea was that they'd happen again soon, leveling Memphis and St Louis. There were even claims that Memphis had greater earthquake hazard than Los Angeles and San Francisco. Nobody gave any thought to whether the warnings of doom made any sense. Could they be true, given that no one in the midwest has ever been killed in an earthquake, whereas thousands have died in California?

We set up a network of benchmarks and measured their positions over six years, to measure the strain building up in the ground that would be released in the upcoming giant earthquake. Andy Newman, who's now a professor at Georgia Tech, analyzed the data for his thesis and found an amazing result - no motion. In other words, no strain was building up, so there's no sign of a giant earthquake coming.

Andy and I talked this over, because the new data would upset a mountain of speculation. We checked this carefully, and it was real. The obvious explanation is that the 1811 and 1812 earthquakes were much smaller than magnitude 8. Sue Hough, who's an expert on using historical data, has gone back to the accounts of those earthquakes and they look like magnitude 7. It turns out they didn't level things in the midwest. In fact damage was very minor.

For that matter, the story that they rang church bells in Boston is wrong. Google gives more than 32,000 references to it, but these are just citing each other. There's no actual account that this happened. It turns out that bells rang in Charleston, South Carolina, which got confused with the Charleston section of Boston. So don't be afraid to go to Memphis to see Graceland or get barbeque - it's a lot safer from earthquakes than going to the AGU meeting in San Francisco.

I could give you lots more examples, just from the tiny sliver of geoscience I've been involved in. At any meeting I go to, I hear a number of neat new results that I would never have thought of. I often wonder "why didn't I think of that?"

From your standpoint, it means there are lots of opportunities for bright young people to discover important things. Don't be afraid to question conventional wisdom and to try to do things differently. Listen to what other people say, but also trust your own judgment.

That's not just true in academic science. The applied side of geoscience is also making huge advances, due to bright people and clever ideas. When I was in school there was concern that we'd soon run out of oil and gas. Now, we're up to our ears in the stuff, due to many advances in exploration and production, including greatly improved seismic imaging. It's now possible to image under salt layers, and make sense of complicated rock geometries that wouldn't have been possible before.

When I got out of school, oil company geophysicists and geologists did exploration, and petroleum engineers did production. Now they work together to find, develop, and operate oil fields. In developing gas wells in shale, they use very accurate locations of tiny earthquakes to map how hydraulic fractures are growing. They recover more oil from existing oil fields by 4-dimensional - space and time - seismic surveys between boreholes to map how the location of fluids change with time.

The result is that instead of running out, we have so much oil and gas that we'll have to leave a lot of it in the ground to prevent global warming from getting out of hand. We also need your generation to figure out how to sequester carbon dioxide in the ground and make sure it stays there.

Your education has given you the tools to do really neat things and have fun doing them. Some of you will stay in geology, and some will decide to do other things. One of my best students is Assistant Director for Science in the Missouri Department of Natural Resources. Although his thesis worked out how microplates along the East Pacific Rise evolve, he's now dealing with flood plain management, fertilizer runoff, giant pig farms (the farm's giant, not the pigs), and other issues.

Whatever you do, what you've learned will be valuable. You may not need to remember the phase diagram for olivine, but the world view will stay with you.

To see that, think about one of the most famous geology graduates in the country. He's sort of a neighbor, living in Arlington. He studied geology at Brooklyn College and did OK, but what he really liked was ROTC. So Colin Powell went into the army, retired as a four star general, and became Secretary of State. I think his geological education helped. When intelligence officers briefed him, he asked: "Tell me what you know. Tell me what don't know. Tell me what you think. Tell me which is which." To me, that's a geologist talking. Someone who recognizes the complexity of the world and approaches it with thoughtful humility, to do the best possible with limited information.

In that spirit, I encourage you to use your knowledge of the earth and your wisdom about it in years to come.

Congratulations and good luck.