Caltech-Led Team Looks in Detail at the April 2015 Earthquake in Nepal

For more than 20 years, Caltech geologist Jean-Philippe Avouac has collaborated with the Department of Mines and Geology of Nepal to study the Himalayas—the most active, above-water mountain range on Earth—to learn more about the processes that build mountains and trigger earthquakes. Over that period, he and his colleagues have installed a network of GPS stations in Nepal that allows them to monitor the way Earth's crust moves during and in between earthquakes. So when he heard on April 25 that a magnitude 7.8 earthquake had struck near Gorkha, Nepal, not far from Kathmandu, he thought he knew what to expect—utter devastation throughout Kathmandu and a death toll in the hundreds of thousands.

"At first when I saw the news trickling in from Kathmandu, I thought there was a problem of communication, that we weren't hearing the full extent of the damage," says Avouac, Caltech's Earle C. Anthony Professor of Geology. "As it turns out, there was little damage to the regular dwellings, and thankfully, as a result, there were far fewer deaths than I originally anticipated."

Using data from the GPS stations, an accelerometer that measures ground motion in Kathmandu, data from seismological stations around the world, and radar images collected by orbiting satellites, an international team of scientists led by Caltech has pieced together the first complete account of what physically happened during the Gorkha earthquake—a picture that explains how the large earthquake wound up leaving the majority of low-story buildings unscathed while devastating some treasured taller structures.

The findings are described in two papers that now appear online. The first, in the journal Nature Geoscience, is based on an analysis of seismological records collected more than 1,000 kilometers from the epicenter and places the event in the context of what scientists knew of the seismic setting near Gorkha before the earthquake. The second paper, appearing in Science Express, goes into finer detail about the rupture process during the April 25 earthquake and how it shook the ground in Kathmandu.

Build Up and Release of Strain on Himalaya Megathrust (caption and credit in video attached in upper right)

In the first study, the researchers show that the earthquake occurred on the Main Himalayan Thrust (MHT), the main megathrust fault along which northern India is pushing beneath Eurasia at a rate of about two centimeters per year, driving the Himalayas upward. Based on GPS measurements, scientists know that a large portion of this fault is "locked." Large earthquakes typically release stress on such locked faults—as the lower tectonic plate (here, the Indian plate) pulls the upper plate (here, the Eurasian plate) downward, strain builds in these locked sections until the upper plate breaks free, releasing strain and producing an earthquake. There are areas along the fault in western Nepal that are known to be locked and have not experienced a major earthquake since a big one (larger than magnitude 8.5) in 1505. But the Gorkha earthquake ruptured only a small fraction of the locked zone, so there is still the potential for the locked portion to produce a large earthquake.

"The Gorkha earthquake didn't do the job of transferring deformation all the way to the front of the Himalaya," says Avouac. "So the Himalaya could certainly generate larger earthquakes in the future, but we have no idea when."

The epicenter of the April 25 event was located in the Gorkha District of Nepal, 75 kilometers to the west-northwest of Kathmandu, and propagated eastward at a rate of about 2.8 kilometers per second, causing slip in the north-south direction—a progression that the researchers describe as "unzipping" a section of the locked fault.

"With the geological context in Nepal, this is a place where we expect big earthquakes. We also knew, based on GPS measurements of the way the plates have moved over the last two decades, how 'stuck' this particular fault was, so this earthquake was not a surprise," says Jean Paul Ampuero, assistant professor of seismology at Caltech and coauthor on the Nature Geoscience paper. "But with every earthquake there are always surprises."

Propagation of April 2015 Mw 7.8 Gorkha Earthquake (caption and credit in video attached in upper right)

In this case, one of the surprises was that the quake did not rupture all the way to the surface. Records of past earthquakes on the same fault—including a powerful one (possibly as strong as magnitude 8.4) that shook Kathmandu in 1934—indicate that ruptures have previously reached the surface. But Avouac, Ampuero, and their colleagues used satellite Synthetic Aperture Radar data and a technique called back projection that takes advantage of the dense arrays of seismic stations in the United States, Europe, and Australia to track the progression of the earthquake, and found that it was quite contained at depth. The high-frequency waves that were largely produced in the lower section of the rupture occurred at a depth of about 15 kilometers.

"That was good news for Kathmandu," says Ampuero. "If the earthquake had broken all the way to the surface, it could have been much, much worse."

The researchers note, however, that the Gorkha earthquake did increase the stress on the adjacent portion of the fault that remains locked, closer to Kathmandu. It is unclear whether this additional stress will eventually trigger another earthquake or if that portion of the fault will "creep," a process that allows the two plates to move slowly past one another, dissipating stress. The researchers are building computer models and monitoring post-earthquake deformation of the crust to try to determine which scenario is more likely.

Another surprise from the earthquake, one that explains why many of the homes and other buildings in Kathmandu were spared, is described in the Science Express paper. Avouac and his colleagues found that for such a large-magnitude earthquake, high-frequency shaking in Kathmandu was actually relatively mild. And it is high-frequency waves, with short periods of vibration of less than one second, that tend to affect low-story buildings. The Nature Geoscience paper showed that the high-frequency waves that the quake produced came from the deeper edge of the rupture, on the northern end away from Kathmandu.

The GPS records described in the Science Express paper show that within the zone that experienced the greatest amount of slip during the earthquake—a region south of the sources of high-frequency waves and closer to Kathmandu—the onset of slip on the fault was actually very smooth. It took nearly two seconds for the slip rate to reach its maximum value of one meter per second. In general, the more abrupt the onset of slip during an earthquake, the more energetic the radiated high-frequency seismic waves. So the relatively gradual onset of slip in the Gorkha event explains why this patch, which experienced a large amount of slip, did not generate many high-frequency waves.

"It would be good news if the smooth onset of slip, and hence the limited induced shaking, were a systematic property of the Himalayan megathrust fault, or of megathrust faults in general." says Avouac. "Based on observations from this and other megathrust earthquakes, this is a possibility."

In contrast to what they saw with high-frequency waves, the researchers found that the earthquake produced an unexpectedly large amount of low-frequency waves with longer periods of about five seconds. This longer-period shaking was responsible for the collapse of taller structures in Kathmandu, such as the Dharahara Tower, a 60-meter-high tower that survived larger earthquakes in 1833 and 1934 but collapsed completely during the Gorkha quake.

To understand this, consider plucking the strings of a guitar. Each string resonates at a certain natural frequency, or pitch, depending on the length, composition, and tension of the string. Likewise, buildings and other structures have a natural pitch or frequency of shaking at which they resonate; in general, the taller the building, the longer the period at which it resonates. If a strong earthquake causes the ground to shake with a frequency that matches a building's pitch, the shaking will be amplified within the building, and the structure will likely collapse.

Turning to the GPS records from two of Avouac's stations in the Kathmandu Valley, the researchers found that the effect of the low-frequency waves was amplified by the geological context of the Kathmandu basin. The basin is an ancient lakebed that is now filled with relatively soft sediment. For about 40 seconds after the earthquake, seismic waves from the quake were trapped within the basin and continued to reverberate, ringing like a bell with a frequency of five seconds.

"That's just the right frequency to damage tall buildings like the Dharahara Tower because it's close to their natural period," Avouac explains.

In follow-up work, Domniki Asimaki, professor of mechanical and civil engineering at Caltech, is examining the details of the shaking experienced throughout the basin. On a recent trip to Kathmandu, she documented very little damage to low-story buildings throughout much of the city but identified a pattern of intense shaking experienced at the edges of the basin, on hilltops or in the foothills where sediment meets the mountains. This was largely due to the resonance of seismic waves within the basin.

Asimaki notes that Los Angeles is also built atop sedimentary deposits and is surrounded by hills and mountain ranges that would also be prone to this type of increased shaking intensity during a major earthquake.

"In fact," she says, "the buildings in downtown Los Angeles are much taller than those in Kathmandu and therefore resonate with a much lower frequency. So if the same shaking had happened in L.A., a lot of the really tall buildings would have been challenged."

That points to one of the reasons it is important to understand how the land responded to the Gorkha earthquake, Avouac says. "Such studies of the site effects in Nepal provide an important opportunity to validate the codes and methods we use to predict the kind of shaking and damage that would be expected as a result of earthquakes elsewhere, such as in the Los Angeles Basin."

Additional authors on the Nature Geoscience paper, "Lower edge of locked Main Himalayan Thrust unzipped by the 2015 Gorkha earthquake," are Lingsen Meng (PhD '12) of UC Los Angeles, Shengji Wei of Nanyang Technological University in Singapore, and Teng Wang of Southern Methodist University. The lead author on the Science paper, "Slip pulse and resonance of Kathmandu basin during the 2015 Mw 7.8 Gorkha earthquake, Nepal imaged with geodesy" is John Galetzka, formerly an associate staff geodesist at Caltech and now a project manager at UNAVCO in Boulder, Colorado. Caltech research geodesist Joachim Genrich is also a coauthor, as are Susan Owen and Angelyn Moore of JPL. For a full list of authors, please see the paper.

The Nepal Geodetic Array was funded by Caltech, the Gordon and Betty Moore Foundation, and the National Science Foundation. Additional funding for the Science study came from the Department of Foreign International Development (UK), the Royal Society (UK), the United Nations Development Programme, and the Nepal Academy for Science and Technology, as well as NASA and the Department of Foreign International Development.

Kimm Fesenmaier
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Preparing for Earthquakes with ShakeAlert

A few seconds may not seem like long, but it is enough time to turn off a stove, open an elevator door, or take cover under a desk. And before an earthquake strikes, a few seconds of warning can save lives. The U.S. Geological Survey aims to provide those seconds of warning with ShakeAlert, an earthquake early-warning system now being tested on the west coast of the United States. On July 30, the USGS announced approximately $4 million in awards to Caltech, UC Berkeley, the University of Washington and the University of Oregon, for the expansion and improvement of the ShakeAlert system.

"Caltech's role in ShakeAlert will focus on research and development of the system so that future versions will be faster and more reliable," says Thomas Heaton (PhD '78), professor of engineering seismology and director of Caltech's Earthquake Engineering Research Laboratory. "We currently collect data from approximately 400 seismic stations throughout California. The USGS grant will allow Caltech to upgrade or install new stations in strategic locations that will significantly improve the performance of ShakeAlert."

Earthquakes radiate two kinds of seismic waves: fast-moving and often harmless P-waves, followed by S-waves, which can cause strong ground shaking. A system of seismometers called the California Integrated Seismic Network (CISN) acquires data streams literally at the speed of light and uses several algorithms to quickly pinpoint the earthquake's epicenter and determine its strength. ShakeAlert analyzes the first P-waves in the CISN data streams to send out digital alerts, providing the "early warning" to a region before the slower, destructive S-waves arrive.

While predicting when and where an earthquake will occur is impossible, this early-warning system can give necessary seconds of preparation. Current beta-test users receive these alerts as a pop-up on their computers, displaying a map of the affected region, the amount of time until shaking begins, the estimated magnitude of the quake, and other data. In the future, alerts may be available through text messages and phone apps.

Though still technically in testing stages, ShakeAlert has already provided successful warnings. In August 2014, the system provided a nine-second warning to the city of San Francisco during a magnitude 6.0 earthquake in South Napa. In May, during a magnitude 3.8 quake in Los Angeles, an alert was issued before S-waves had even reached the earth's surface.

"With this new USGS funding, we will be able to add 20 new sensors to CISN, making coverage more robust and thus lengthening warning times," says Egill Hauksson, a research professor of geophysics and a principal investigator along with Heaton on the ShakeAlert project. "Caltech and its partners will be able to continue the high-quality seismological research that is such a necessary foundation for a reliable earthquake early-warning system."

In 2011, Caltech, along with UC Berkeley and the University of Washington, Seattle, received $6 million from the Gordon and Betty Moore Foundation for the research and development of ShakeAlert.

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$100 Million Gift from Gordon and Betty Moore Will Bolster Graduate Fellowships

Trustees Gordon (PhD '54) and Betty Moore have pledged $100 million to Caltech, the second-largest single contribution in the Institute's history. With this gift, they have created a permanent endowment and entrusted the choice of how to direct the funds to the Institute's leadership—providing lasting resources coupled with uncommon freedom.

"Those within the Institute have a much better view of what the highest priorities are than we could have," Intel Corporation cofounder Gordon Moore explains. "We'd rather turn the job of deciding where to use resources over to Caltech than try to dictate it from outside."

Applying the Moores' donation in a way that will strengthen the Institute for generations to come, Caltech's president and provost have decided to dedicate the funds to fellowships for graduate students.

"Gordon and Betty Moore's incredibly generous gift will have a transformative effect on Caltech," says President Thomas F. Rosenbaum, holder of the Institute's Sonja and William Davidow Presidential Chair and professor of physics. "Our ultimate goal is to provide fellowships for every graduate student at Caltech, to free these remarkable young scholars to pursue their interests wherever they may lead, independent of the vicissitudes of federal funding. The fellowships created by the Moores' gift will help make the Institute the destination of choice for the most original and creative scholars, students and faculty members alike."

Further multiplying the impact of the Moores' contribution, the Institute has established a program that will inspire others to contribute as well. The Gordon and Betty Moore Graduate Fellowship Match will provide one additional dollar for every two dollars pledged to endow Institute-wide fellowships. In this way, the Moores' $100 million commitment will increase fellowship support for Caltech by a total of $300 million.

Says Provost Edward M. Stolper, the Carl and Shirley Larson Provostial Chair and William E. Leonhard Professor of Geology: "Investigators across campus work with outstanding graduate students to advance discovery and to train the next generation of teachers and researchers. By supporting these students, the Moore Match will stimulate creativity and excellence in perpetuity all across Caltech. We are grateful to Gordon and Betty for allowing us the flexibility to devote their gift to this crucial priority."

The Moores describe Caltech as a one-of-a-kind institution in its ability to train budding scientists and engineers and conduct high-risk research with world-changing results—and they are committed to helping the Institute maintain that ability far into the future.

"We appreciate being able to support the best science," Gordon Moore says, "and that's something that supporting Caltech lets us do."

The couple's extraordinary philanthropy already has motivated other benefactors to follow their example, notes David L. Lee, chair of the Caltech Board of Trustees.

"The decision that Gordon and Betty made—to give such a remarkable gift, to make it perpetual through an endowment, and to remove any restrictions as to how it can be used—creates a tremendous ripple effect," Lee says. "Others have seen the Moores' confidence in Caltech and have made commitments of their own. We thank the Moores for their leadership."

The Moores consider their gift a high-leverage way of fostering scientific research at a place that is close to their hearts. Before he went on to cofound Intel, Gordon Moore earned a PhD in chemistry from Caltech.

"It's been a long-term association that has served me well," he says.

Joining him in Pasadena just a day after the two were married, Betty Moore became active in the campus community as well. A graduate of San Jose State College's journalism program, she secured a job at the Ford Foundation's new Pasadena headquarters and also made time to come to campus to participate in community activities, including the Chem Wives social club.

"We started out at Caltech," she recalls. "I had a feeling that it was home away from home. It gives you a down-home feeling when you're young and just taking off from family. You need that connection somehow."

After earning his PhD from Caltech in 1954, Gordon Moore took a position conducting basic research at the Applied Physics Laboratory at Johns Hopkins University. Fourteen years and two jobs later, he and his colleague Robert Noyce cofounded Intel Corp. Moore served as executive vice president of the company until 1975, when he took the helm. Under his leadership—as chief executive officer (1975 to 1987) and chairman of the board (1987 to 1997)—Intel grew from a Mountain View-based startup to a giant of Silicon Valley, worth more than $140 billion today.

Moore is widely known for "Moore's Law," his 1965 prediction that the number of transistors that can fit on a chip would double every year. Still relevant 50 years later, this principle pushed Moore and his company—and the tech industry as a whole—to produce continually more powerful and cheaper semiconductor chips.

Gordon Moore joined the Caltech Board of Trustees in 1983 and served as chair from 1993 to 2000. That same year, he and his wife established the Gordon and Betty Moore Foundation, an organization dedicated to creating positive outcomes for future generations in the San Francisco Bay Area and around the world.

Among numerous other honors, Gordon Moore is a member of the National Academy of Engineering, a fellow of the Institute of Electrical and Electronics Engineers, and a recipient of the National Medal of Technology and the Presidential Medal of Freedom. 

The Gordon and Betty Moore Graduate Fellowship Match is available for new gifts and pledges to endow graduate fellowships. For more information about the match and how to support graduate education at Caltech, please contact Jon Paparsenos, executive director of development, at (626) 395-3088 or

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Alone in the Darkness: Mariner 4 to Mars, 50 Years Later

July 14 marks 50 years of visual reconnaissance of the solar system by NASA's Jet Propulsion Laboratory (JPL), beginning with Mariner 4's flyby of Mars in 1965.

Among JPL's first planetary efforts, Mariners 3 and 4 (known collectively as "Mariner Mars") were planned and executed by a group of pioneering scientists at Caltech in partnership with JPL. NASA was only 4 years old when the first Mars flyby was approved in 1962, but the core science team had been working together at Caltech for many years. The team included Caltech faculty Robert Sharp (after whom Mount Sharp, the main target of the Mars rover Curiosity, is named) and Gerry Neugebauer, professor of geology and of professor of physics, respectively; Robert Leighton and H. Victor Neher, professors of physics; and Bill Pickering, professor of electrical engineering, who was the director of JPL from 1954–1976. Rounding out the Caltech contingent was a young Bruce Murray, a new addition to the geology faculty, who would follow Pickering as JPL director in 1976.

"The Mariner missions marked the beginning of planetary geology, led by researchers at Caltech including Bruce Murray and Robert Sharp," said John Grotzinger, the Fletcher Jones Professor of Geology and chair of the Division of Geological and Planetary Sciences. "These early flyby missions showed the enormous potential of Mars to provide insight into the evolution of a close cousin to Earth and stimulated the creation of a program dedicated to iterative exploration involving orbiters, landers, and rovers."

By today's standards, Mariner Mars was a virtual leap into the unknown. NASA and JPL had little spaceflight experience to guide them. There had been just one successful planetary mission—Mariner 2's journey past Venus in 1962—to build upon. Sending spacecraft to other planets was still a new endeavor.  

The Mariner Mars spacecraft were originally designed without cameras. Neugebauer, Murray, and Leighton felt that a lot of science questions could be answered via images from this close encounter with Mars. As it turned out, sending back photos of the planet that had so long captured the imaginations of millions had the added benefit of making the Mars flyby more accessible to the public.

Mariner 3 launched on November 5, 1964. The Atlas rocket that boosted it clear of the atmosphere functioned perfectly (not always the case in the early years of spaceflight), but the shroud enclosing the payload failed to fully open and the spacecraft, unable to collect sunlight on its solar panels, ceased to function after about nine hours of flight.

Mariner 4 launched three weeks later on November 28 with a redesigned shroud. The probe deployed as planned and began its journey to Mars. But there was still drama in store for the mission. Within the first hour of the flight, the rocket's upper stage had pushed the spacecraft out of Earth orbit, and the solar panels had deployed. Then the guidance system acquired a lock on the sun, but a second object was needed to guide the spacecraft. This depended on a photocell finding the bright star Canopus, which was attempted about 15 hours later. During these first attempts, however, the primitive onboard electronics erroneously identified other stars of similar brightness.

Controllers managed to solve this problem but over the next few weeks realized that a small cloud of dust and paint flecks, ejected when Mariner 4 deployed, was traveling along with the spacecraft and interfering with the tracking of Canopus. A tiny paint chip, if close enough to the star tracker, could mimic the star. After more corrective action, Canopus was reacquired and Mariner's journey continued largely without incident. This star-tracking technology, along with many other design features of the spacecraft, has been used in every interplanetary mission JPL has flown since.

At the time, what was known about Mars had been learned from Earth-based telescopes. The images were fuzzy and indistinct—at its closest, Mars is still about 35 million miles distant. Scientific measurements derived from visual observations of the planet were inexact. While ideas about the true nature of Mars evolved throughout the first half of the 20th century, in 1965 nobody could say with any confidence how dense the martian atmosphere was or determine its exact composition. Telescopic surveys had recorded a visual event called the "wave of darkening," which some scientists theorized could be plant life blooming and perishing as the harsh martian seasons changed. A few of them still thought of Mars as a place capable of supporting advanced life, although most thought it unlikely. However, there was no conclusive evidence for either scenario.

So, as Mariner 4 flew past Mars, much was at stake, both for the scientific community and a curious general public. Were there canals or channels on the surface, as some astronomers had reported? Would we find advanced life forms or vast collections of plant life? Would there be liquid water on the surface?

Just over seven months after launch, the encounter with Mars was imminent. On July 14, 1965, Mariner's science instruments were activated. These included a magnetometer to measure magnetic fields, a Geiger counter to measure radiation, a cosmic ray telescope, a cosmic dust detector, and the television camera.

About seven hours before the encounter, the TV camera began acquiring images. After the probe passed Mars, an onboard data recorder—which used a 330-foot endless loop of magnetic tape to store still pictures—initiated playback of the raw images to Earth, transmitting them twice for certainty. Each image took 10 hours to transmit.

The 22 images sent by Mariner 4 appeared conclusive. Although they were low-resolution and black-and-white, they indicated that Mars was not a place likely to be friendly to life. It was a cold, dry desert, covered with so many craters as to strongly resemble Earth's moon. The atmospheric density was about one-thousandth that of Earth, and no liquid water was apparent on the surface.

When discussing the mission during an interview at Caltech in 1977, Leighton recalled viewing the first images at JPL. "If someone had asked 'What do you expect to see?' we would have said 'craters'…[yet] the fact that craters were there, and a predominant land form, was somehow surprising."

Leighton also recalled a letter he received from, of all people, a dairy farmer. It read, "I'm not very close to your world, but I really appreciate what you are doing. Keep it going." Leighton said of the sentiment, "A letter from a milkman…I thought that was kind of nice."

After its voyage past Mars, Mariner 4 maintained intermittent communication with JPL and returned data about the interplanetary environment for two more years. But by the end of 1967, the spacecraft had suffered tens of thousands of micrometeoroid impacts and was out of the nitrogen gas it used for maneuvering. The mission officially ended on December 21.

"Mariner 4 defined and pioneered the systems and technologies needed for a truly interplanetary spacecraft," says Rob Manning (BS '81), JPL's chief engineer for the Low-Density Supersonic Decelerator and formerly chief engineer for the Mars Science Laboratory. "All U.S. interplanetary missions that have followed were directly derived from the architecture and innovations that engineers behind Mariner invented. We stand on the shoulders of giants."

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New VP for Student Affairs Named

Joseph Shepherd (PhD '81), the C. L. "Kelly" Johnson Professor of Aeronautics and professor of mechanical engineering, is leaving his post as dean of graduate studies to succeed Anneila Sargent (MS '67, PhD '78), the Ira S. Bowen Professor of Astronomy, as vice president for student affairs. Shepherd's new role is effective September 15.

Sargent, who served the campus as the leader of student affairs the last eight years, announced in March that she was leaving the post to return to research and teaching full time. Shepherd, who joined the Caltech faculty in 1993, has served the last six years as the dean of graduate studies.

We recently sat down with Shepherd to talk about his past role and his new one, his strengths and goals, and his experience at Caltech.


Q: What does the vice president for student affairs do?

A: Student Affairs includes the offices of the undergraduate and graduate deans as well as obvious things like the registrar, undergraduate admissions, fellowships and study abroad, the career center, the health center, and the counseling center. It also includes things you might not think of—athletics; performing and visual arts, which includes the music programs, the theater program, the various arts programs, and all of the faculty and instructors that make these programs possible; and a whole group of organizations lumped under "auxiliaries."

The term "auxiliaries" is misleading, because they're central to student life. Housing and dining are the biggest parts, but there are services like the C-Store, the Red Door Café, the Caltech Store and Wired.


Q: What makes this role exciting for you?

A:  People speculate about what it is that makes Caltech a great school. A lot of folks say, "Well, it's because it's so small." But I think it's also because we work with people instead of creating some bureaucratic mechanism to solve problems. We say, "All right, what's the issue here? How can we resolve this?" instead of, "We need to create a rule. And then we need to create a group to enforce the rule." My approach is to ask, "What do we want the outcome to be?" In Student Affairs, you want the outcome to be something that supports the students, supports the faculty, and then you make sure that it's not going to adversely affect the Institute.


Q: Are there any changes coming, any initiatives you want to establish?

A: We need to think about how we build on the strengths we have and improve the things that we're weakest at. Before you make any changes to an organization, you need to understand those two things. There are a lot of parts to Student Affairs, so I need to understand the strong points of those organizations, and then get them to help me formulate what's important to do.

You always have to be careful of unintended consequences. As they say in chess, you want to think several moves deep. All right, suppose we do that. What will it mean for different parts of our population? Do we make this choice based on the data we have, or do we need more data? Will there be effects on people we haven't thought about? Maybe we need to go talk to those people.

When you have the authority to change things, you also have the responsibility to ask, "Are these the right changes?" Nothing happens in isolation. Anything you do is invariably going to wind up touching quite a few people.


Q: You've been dean of graduate studies since 2009. Did you consider taking a breather before jumping into this?

A: Well, much to my surprise, I found that being the dean of graduate studies was rewarding in many different ways. Sometimes you had to do some difficult things, but I actually liked being the dean. I was able, to some extent, to continue my research. I did some teaching—although last year I taught a major course all three terms, and I had my research group—and I was the dean of graduate studies. That taught me a lesson: a man's got to know his limitations.

So when I was asked if I would take this position, I did think about taking a break and not doing it. I enjoy my research and I enjoy teaching. I enjoy working with students, but I also enjoy trying to help the Institute as a whole. Here at Caltech, we pride ourselves on the notion that we have this very special environment. We have this small school, and we have dedicated professionals that work together with faculty to nurture that environment—having faculty who are invested in participating in the key administrative roles is essential.

When I was a graduate student here, my adviser was Brad Sturtevant [MS '56, PhD '60, and a lifelong faculty member thereafter]. Brad was the executive officer for aeronautics [1972-76]. He was in charge of the committee that built the Sherman Fairchild Library and he was on the faculty board. He emphasized to me that being involved in administration was just as valuable as all the other aspects of being a faculty member. He was a dedicated researcher, but he also felt strongly that you should be a good citizen. You should contribute.


Q: It seems like this is more than just a duty to you, though.

A: I'm looking forward to it. I'm also very conscious of the responsibility. I think it's going to be important for us all to think about how we maintain the excellence of the Institute and that we imagine how this place is going to evolve. As society evolves around us, we will naturally wind up changing. We need to do that in a thoughtful way so that we continue to be the special organization that we are.

At the end of the day, I'm counting on help from the faculty and staff. Caltech works because of the committed individuals within our organizations, the personal connections we form as we work together and the cooperation across the campus that these connections enable.  It's a collective enterprise.

I think administration is not something that's done to people. It's being responsible for making sure that folks have the right work environment, the right job assignments, and the right resources. It's making sure we're doing the right things with the finite resources we have. One of our former presidents said something that's always stuck with me: an administrator's goals are not about their own career so much as helping the careers of others. You need to think about how you're helping the people working for you, because they have goals and aspirations. That's where you take your satisfaction.

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Understanding Monsoons

Studies of the global environment are complex, involving interactions between oceans, solid earth, biological systems, and the atmosphere, over time scales ranging from nanoseconds to millions of years. Investigating and understanding these complicated and interconnected systems is the goal of Caltech's Ronald and Maxine Linde Center for Global Environmental Science. To that end, the center hosts workshops that bring together scientists from a range of disciplines to discuss current research and collaborate on solutions to pressing issues facing the global environment.

"The Linde Center workshops aim to provide a venue for a small group of scientists and engineers to discuss and put forward cutting edge, 'future-looking' plans for global environmental science," says Paul Wennberg, the R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering and director of the Linde Center.

The topic of the center's latest workshop, held May 18–22, was monsoons, circulation patterns that develop over subtropical continents (up to around latitude 30 degree north and south of the equator) in response to seasonal variations in the amount of solar radiation received in these regions. Monsoons are characterized by seasonally reversing winds and summertime rainfall. Although monsoons occur across the globe, they are more often studied in Southeast Asian countries—where warm, moist air from the Indian Ocean brings humidity and rainfall during the summer, while winds from the northeast produce dry winters—and in West Africa. Because of their effects on the water supply, monsoons have a large impact on society, especially in densely populated countries and rapidly growing economies. And, as noted by the workshop organizers, "with projected increases in population and pressure for food and water security, understanding how anthropogenic climate change will affect monsoons is both a priority and a major challenge in climate science."

Indeed, the workshop—entitled "Monsoons: Past, Present, and Future" and co-led by monsoon researcher Simona Bordoni, assistant professor of environmental science and engineering at Caltech—was focused on understanding how monsoons have changed and how they will change in the future, across a variety of time scales, in response to different forcing agents—perturbations of Earth's energy balance caused by changing environmental parameters such as solar variability or human-induced greenhouse gas emissions.

"One of the central themes of the discussion," Bordoni says, "was how modern theories of the fundamental dynamics of monsoons can be used to better constrain future monsoon projections and past monsoon changes and shifts recorded by paleo-proxies"—media such as tree rings and ice cores that preserve information about past climates—"and how these paleo-reconstructions can provide support to emerging hypotheses and guide modeling studies. The implications of these modern theories are only now beginning to be explored."

Each section of the invitation-only workshop covered a particular subject area within monsoon research, including paleoclimate, aerosols, the intertropical convergence zone (the band of clouds encircling the equator), and thermal contrasts between land and sea. Speakers from institutions around the country gave talks on past and potential future changes in the monsoon cycle, the role of aerosols on monsoon circulation, and monsoon modeling, among other topics.

In a talk entitled "Monsoons on Idealized Continents," for example, Bordoni discussed how she uses models of "idealized" continental geometry to study how monsoons would develop on hypothetical planets—for example, a planet with land everywhere above 10 degrees north of the equator, and ocean everywhere south of that. Recently, Bordoni and her group also created simulations of an "aquaplanet"—a planet entirely covered with ocean. With the aquaplanet simulations, the team demonstrated that the rapid onset of large-scale monsoons, such as the Asian monsoon, results not from temperature differences between oceans and land, as previously believed. Instead, they found, the rapid appearance of this monsoon is controlled by the interaction between large swirling regions of turbulent air called eddies and the tropical circulation. These eddies, which are generated in mid-latitudes, propagate to lower latitudes towards the subtropics and interact with the tropical circulation, causing it to reverse rapidly, initiating the onset of the monsoon. Bordoni's group also studies the North American monsoon, which usually occurs during the summer over southwestern North America, when warm and moist air moving northwest from the Gulf of California meets similar air moving northwest from the Gulf of Mexico; the dynamics of the East Asian monsoon and its response to climate changes; the year-to-year variability of the Indian monsoon; and how mountain ranges such as those in Africa and Asia influence the larger-scale circulation of this monsoon.

The workshop was co-led by Timothy Merlis (Ph.D. '11), an assistant professor in atmospheric and oceanic sciences at McGill University. He gave a talk on tropical circulation changes influenced by various forcing agents. Other speakers from Caltech included Jess Adkins, professor of geochemistry and global environmental science, who gave a talk on historical precipitation variability over Borneo as measured in stalagmites; Salvatore Pascale, a NOAA Climate and Global Change postdoctoral scholar in environmental science and engineering; and Ho Hsuan Wei, a graduate student in environmental science and engineering. Hui Su, a JPL atmospheric scientist, gave a talk on the tropical Hadley cell (a pattern of atmospheric circulation in which warm air rises near the equator, cools as it travels at high altitude toward the poles, then sinks as cold air and warms as it travels toward the equator) and feedback from clouds. In addition, JPL scientist Christian Frankenberg—who will join the Caltech faculty in September as an associate professor of environmental science and engineering—discussed remote sensing of water isotopes.

The previous Linde Center workshop was held February 2–5 and focused on physical, chemical, and biological processes crucial to the circulation and ecosystems of the Southern Ocean around Antarctica.

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Thursday, September 24, 2015
Beckman Institute, Glanville Courtyard – Beckman Institute

3rd Annual Caltech Teaching Conference

New Dean of Graduate Studies Named

On July 1, 2015, Doug Rees, the Roscoe Gilkey Dickinson Professor of Chemistry, will begin serving as the new dean of graduate studies at Caltech.

"Doug's experience and concern with graduate education make him an ideal choice for dean of graduate studies. I am very pleased that he is willing to make this commitment to the Institute and its students," says Anneila Sargent, vice president for student affairs and the Ira S. Bowen Professor of Astronomy.

As the new dean, Rees will be the principal administrator and representative of Caltech's graduate education program, responsible for attending to concerns regarding the welfare of graduate students as well as for upholding the Institute's rules and policies.

"There are many groups essential to the effective operation of our graduate program that I want to get to know better, starting with the graduate students, the Graduate Office staff, and the option administrators and option reps," says Rees. "In my 26 years at Caltech, I've gained an appreciation for how the graduate programs in biochemistry and molecular biophysics and in chemistry operate, but the cultures in different options across campus can vary significantly, and I look forward to better understanding these distinctions."

Rees says that he is also very much looking forward to working directly with graduate students, staff, and faculty on behalf of the graduate program. Of particular interest during his tenure will be issues relating to the well-being and professional development of graduate students.

"I find research to be an adventure that, while exhilarating, is also challenging, frustrating, and even stressful; those aspects, however, are not incompatible with having a positive student experience and a supportive environment," Rees says. He adds that his priorities will be to raise fellowship support, increase the diversity of the graduate student body, and ensure that students have access to appropriate support services such as health care, counseling, and day care. "In addition, I also hope to be able to explore mechanisms to better prepare students for life after Caltech, including both academic and nonacademic career options," he says.

In his new post, Rees will take the place of C. L. "Kelly" Johnson Professor of Aeronautics and Mechanical Engineering Joseph Shepherd, who has served as the dean of graduate studies since 2009. "Joe leaves big shoes to fill and the campus owes him a huge debt of gratitude for all he has accomplished as dean of graduate studies. What I have learned from watching him in action over the past six years, and more recently as he has been helping me during this transition period, is that the most important quality for the dean is to care about the students—and I will definitely be working to follow his example," Rees says.

Rees received his undergraduate degree from Yale University in 1974 and his PhD from Harvard in 1980, becoming a professor at Caltech in 1989. An investigator with the Howard Hughes Medical Institute, Rees also served as the executive officer for chemistry from 2002 to 2006 and the executive officer for biochemistry and molecular biophysics from 2007 to 2015.

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JPL News: NASA Joins North Sea Oil Cleanup Training Exercise

NASA participated for the first time in Norway's annual oil spill cleanup exercise in the North Sea on June 8 through 11. Scientists flew a specialized NASA airborne instrument called the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) on NASA's C-20A piloted research aircraft to monitor a controlled release of oil into the sea, testing the radar's ability to distinguish between more and less damaging types of oil slicks.

Read the full story from JPL News

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Caltech, JPL Team Up to Take On Big-Data Projects

Acknowledging not only the growing need among scientists and engineers for resources that can help them handle, explore, and analyze big data, but also the complementary strengths of Caltech's Center for Data-Driven Discovery (CD3) and JPL's Center for Data Science and Technology (CDST), the two centers have formally joined forces, creating the Joint Initiative on Data Science and Technology.

A kickoff event for the collaboration was held at the end of April at Caltech's Cahill Center for Astronomy and Astrophysics.

"This is a wonderful example of a deep cooperation between Caltech and JPL that we think will serve to strengthen connections between the campus and the lab," says George Djorgovski, professor of astronomy and director of CD3. "We believe the joint venture will enable and stimulate new projects and give both campus and JPL researchers a new competitive advantage."

Individually, each center strives to provide the intellectual infrastructure, including expertise and advanced computational tools, to help researchers and companies from around the world analyze and interpret the massive amounts of information they now collect using computer technologies, in order to make data-driven discoveries more efficient and timely.

"We've found a lot of synergy across disciplines and an opportunity to apply emerging capabilities in data science to more effectively capture, process, manage, integrate, and analyze data," says Daniel Crichton, manager of the CDST. " JPL's work in building observational systems can be applied to several disciplines from planetary science and Earth science to biological research."

The Caltech center is also interested in this kind of methodology transfer—the application of data tools and techniques developed for one field to another. The CD3 recently collaborated on one such project with Ralph Adolphs, Bren Professor of Psychology and Neuroscience and professor of biology at Caltech. They used tools based on machine learning that were originally developed to analyze data from astronomical sky surveys to process neurobiological data from a study of autism.

"We're getting some promising results," says Djorgovski. "We think this kind of work will help researchers not only publish important papers but also create tools to be used across disciplines. They will be able to say, 'We've got these powerful new tools for knowledge discovery in large and complex data sets. With a combination of big data and novel methodologies, we can do things that we never could before.'"

Both the CD3 and the CDST began operations last fall. The Joint Initiative already has a few projects under way in the areas of Earth science, cancer research, health care informatics, and data visualization.

"Working together, we believe we are strengthening both of our centers," says Djorgovski. "The hope is that we can accumulate experience and solutions and that we will see more and more ways in which we can reuse them to help people make new discoveries. We really do feel like we're one big family, and we are trying to help each other however we can."

Kimm Fesenmaier
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