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The personal side of science

Wednesday, February 4, 2015
Center for Student Services 360 (Workshop Space) – Center for Student Services

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Grotzinger Steps Down as Curiosity’s Project Scientist

Caltech geologist John Grotzinger, who was recently named chair of the Division of Geological and Planetary Sciences, has stepped down as project scientist for NASA's Mars Rover Curiosity. He is succeeded by Ashwin Vasavada (PhD '98) of JPL.

Grotzinger, the Fletcher Jones Professor of Geology at Caltech, has served as project scientist for Curiosity's mission, the Mars Science Laboratory (MSL), since 2007. Prior to that, he had been actively involved as a member of the science team for both the Mars Exploration rovers and the Mars Reconnaissance Orbiter.

Since Curiosity's suspenseful landing on Mars in August 2012—dubbed the "Seven Minutes of Terror"—its team of scientists has discovered an ancient alluvial fan and lake system that filled in a 3.6 billion year-old impact crater the size of the Los Angeles basin. The science team also determined that the chemistry of this geologic system would have supported microbial chemolithotrophy—the usage of inorganic compounds as a source of energy—if life had ever evolved on Mars.

"I have considered it a privilege to help guide the MSL mission for almost eight years," remarks Grotzinger. "We accomplished the principal goal of the mission—to find an ancient habitable environment—and I will now enjoy spending more time working on the mission data as a science team member."

Grotzinger's successor, Vasavada, had been deputy project scientist for MSL for the last 10 years. He has also worked on the science teams for NASA's Lunar Reconnaissance Orbiter and for the Cassini mission to Saturn. He earned his doctorate in planetary science from Caltech's Division of Geological and Planetary Sciences.

"Ashwin Vasavada is a great choice as the next project scientist," says Grotzinger. "He has a very strong technical background, an intimate understanding of the science instruments and rover flight systems, and brings real passion for the exploration of Mars."

For more about this transition, read JPL's release.

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Wednesday, February 18, 2015
Center for Student Services 360 (Workshop Space) – Center for Student Services

HALF TIME: A Mid-Quarter Meetup for TAs

Remembering Don L. Anderson

1933–2014

Don L. Anderson, the Eleanor and John R. McMillan Professor of Geophysics, Emeritus, passed away on December 2, 2014. He was 81 years old.

Anderson's work helped advance our understanding of the composition, structure, and dynamics of the earth and of earth-like planets. He was a pioneer in the use of seismic anisotropy—variations in the velocities of seismic waves as they move at different angles through materials—to study the earth's interior. This allowed him and others to learn more about the boundaries of the planet's mantle.

"Caltech has lost a towering figure in geophysics with the passing of Don Anderson," says Michael Gurnis, the John E. and Hazel S. Smits Professor of Geophysics. "Don left an indelible mark not just on the Seismological Laboratory but on the field of global seismology and whole-earth geophysics. He was an unusual scientist who often advocated unpopular theories and concepts. Perhaps more than anyone else, DLA—as he was fondly known in the Seismo Lab—knew how uncertain many of our observations and theories were, especially those of the earth's deep interior. By advocating the unpopular, Don challenged our ideas and forced us to make the observations needed to resolve our understanding of earthquakes and the deep earth."

In 1981, Anderson developed, with Adam Dziewonski of Harvard University, the Preliminary Reference Earth Model (PREM), a one-dimensional model representing the average properties of the earth, including seismic velocities, attenuation, and density, as a function of planetary radius. PREM continues to be the most widely used standard model of the earth. Anderson, a former president (1988–1990) of the American Geophysical Union, is the author of the book, Theory of the Earth, a 1989 reference on the origin, composition, and evolution of Earth's interior. In 2007, Anderson published New Theory of the Earth, a completely updated version.

Born in Frederick, Maryland, on March 5, 1933, the son of a schoolteacher and an electrician, Anderson received his BS in geology and geophysics from Rensselaer Polytechnic University in 1955. He worked for Chevron Oil Company from 1955 to 1956, the Air Force Cambridge Research Center from 1956 to 1958, and the Arctic Institute of North America from 1958 to 1960.

His service with the Air Force took him to Greenland, where his job was to determine how thick the ice had to be to support aircraft that were in trouble. "The Air Force wanted their pilots to land disabled planes on the sea ice, but the conventional wisdom at the time was that they would break through the ice and the crew would freeze to death," Anderson recalled in a 2001 oral history. Anderson and his colleagues found that, in fact, aircraft can land very easily on ice that is not very thick: "Even if the ice won't support the plane while it's sitting there, it will allow a plane to taxi long enough for the pilots to get out and then the plane can sink through the ice, or the wheels can poke through the ice. Our job was to study ice strength, and whether you could determine how strong it was before you landed so you would know where to land." The project continued after Anderson entered graduate school at Caltech, where he earned a master's degree in geophysics in 1959 and a doctorate in geophysics in 1962 under the supervision of Frank Press.

Upon his graduation from Caltech, Anderson was hired as a research fellow; he became an assistant professor in 1963, an associate professor in 1964, and a professor in 1968. From 1967 to 1989, Anderson was director of Caltech's Seismological Laboratory.

"Those who were fortunate enough to be at the Seismo Lab with Don since the 1960s have greatly benefited from the interaction with him, and his influence will have long-lasting effects on our work for years to come," says Hiroo Kanamori, the John E. and Hazel S. Smits Professor of Geophysics, Emeritus. "As many of the Seismo Lab alumni would testify, we all benefited tremendously from the Seismo Lab coffee break discussions where Don was always at the center. Occasionally, he forcefully presented his idea, but more often he was a good listener too. Then, we later received notes and reprints on the subjects discussed, and if we were really interested in the subject, we would pursue it in depth and eventually write an interesting paper. Many of my papers grew out of the coffee break discussions."

"Don was a inspiring geoscientist who motivated his students and many younger colleagues to think deeply, broadly, and creatively about the Earth and other planets," says Thomas Jordan (PhD '72), a former student of Anderson's who is now the William M. Keck Foundation Chair in Geological Sciences and professor of Earth sciences at the University of Southern California.

Provost Edward Stolper, the William E. Leonhard Professor of Geology and the Carl and Shirley Larson Provostial Chair, agreed, saying "Don had a significant impact on my career—both as a supportive, probing, and intellectually challenging colleague, and as a friend.

"As a graduate student at Harvard, I heard Don lecture about the possibility of there being a CAI-like zone around the earth's core and about the composition of the moon. CAI's are calcium-aluminum inclusions in chondritic meteorites and represent the very earliest solid materials formed in the solar system. I was energized by what Don had said and knew at that point I wanted to be at Caltech," says Stolper.

Anderson was the Eleanor and John R. McMillan Professor from 1989 until his retirement in 2002.

"Don had a tremendous influence on the development of geophysics and global seismology in the United States," says Gurnis, the current director of Caltech's Seismological Laboratory. "One of DLA's unwavering passions since the 1960s was to map the earth's deep interior associated with surface processes. He was instrumental in founding the NSF-funded IRIS—Incorporated Research Institutions for Seismology—and the development of what became known as the GSN—the Global Seismic Network—in the 1980s. Through these major U.S. programs, we were able to map out the nature of the forces associated with plate tectonics and volcanism."

Anderson continued to work and publish until his death. His most recent work on volcanism was showcased at the fall meeting of the American Geophysical Union in San Francisco in December 2014.

A fellow of the American Academy of Arts and Sciences and a member of the National Academy of Sciences and the American Philosophical Society, Anderson was also the recipient of the Emil Wiechert Medal of the German Geophysical Society, the Arthur L. Day Medal of the Geological Society of America, the Gold Medal of the Royal Astronomical Society, the William Bowie Medal of the American Geophysical Union, and the Crafoord Prize of the Royal Swedish Academy of Sciences.

In 1998, Anderson was awarded the National Medal of Science and was cited for his "immeasurable influence on the advancement of earth sciences over the past three decades nationally and internationally."

Anderson is survived by his wife, Nancy; daughter, Lynn Rodriguez; son, Lee Anderson; and four granddaughters.

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Kanamori Receives Sacred Treasure from Japanese Government

Hiroo Kanamori, Caltech's John E. and Hazel S. Smits Professor of Geophysics, Emeritus, has been awarded the Order of the Sacred Treasure Gold and Silver Star by the government of Japan for his "contribution to education and research."

The Order of the Sacred Treasure was introduced by the Japanese government in 1888 to recognize outstanding achievements in myriad areas, including research, education, business, and health care. After receiving his undergraduate degree and PhD from the University of Tokyo, Kanamori spent 10 years as a researcher and professor at the university's Geophysics Department and Earthquake Research Institute. He returned as a visiting lecturer this year.

Kanamori moved to Caltech in 1972, where he worked on the mechanism of world great earthquakes and developed in 1977 a way of quantifying an earthquake in terms of the amount of energy it releases. His current research is on the physics of earthquakes, and he is also working on new detection methods for early warning systems.

Kanamori was nominated by the Japanese Ministry of Education, Culture, Sports, Science and Technology. He received the award from Japan's Prime Minister, Shinzo Abe, in a conferment ceremony in Tokyo on November 5, 2014. The Emperor of Japan, Tsugunomiya Akihito, was also present.

"I enjoyed seeing the emperor," says Kanamori. "He is a good scientist himself."

Kanamori has also been named the 2014 recipient of the William Bowie Medal, the highest award given by the American Geophysical Union (AGU), which he received at the 47th annual meeting of the AGU on December 17, 2014, in San Francisco.

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Don L. Anderson

1933–2014

Don L. Anderson, the Eleanor and John R. McMillan Professor of Geophysics, Emeritus, passed away on December 2, 2014. He was 81 years old.

Anderson's work helped advance our understanding of the composition, structure, and dynamics of Earth and Earth-like planets. He was a pioneer in the use of seismic anisotropy—variations in the velocities of seismic waves as they move at different angles through materials—to study Earth's interior, which allowed him to help discover and explain the boundaries of the planet's mantle.

In 1981, Anderson codeveloped, with geophysicist Adam Dziewonski, the preliminary reference Earth model (PREM), a one-dimensional model representing the average properties of Earth, including seismic velocities, attenuation, and density, as a function of planetary radius. PREM continues to be the most widely used standard model of Earth. Anderson, a former president (1988-1990) of the American Geophysical Union, is the author of the textbook, Theory of the Earth, a 1989 reference on the origin, composition, and evolution of Earth's interior. A completely updated version, New Theory of the Earth, was published in 2007.

Born in Frederick, Maryland, on March 5, 1933, the son of a schoolteacher and an electrician, Anderson received his BS in geology and geophysics from Rensselaer Polytechnic University in 1955. He worked for Chevron Oil Company from 1955 to 1956, the Air Force Cambridge Research Center from 1956 to 1958, and the Arctic Institute of North America from 1958 to 1960.

His service with the Air Force took him to Greenland, where his job was to determine how thick the ice had to be to support aircraft that were in trouble. "The Air Force wanted their pilots to land disabled planes on the sea ice, but the conventional wisdom at the time was that they would break through the ice and the crew would freeze to death," Anderson recalled in a 2001 oral history. Anderson and his colleagues found that, in fact, aircraft can land very easily on ice that is not very thick: "Even if the ice won't support the plane while it's sitting there, it will allow a plane to taxi long enough for the pilots to get out and then the plane can sink through the ice, or the wheels can poke through the ice. Our job was to study ice strength, and whether you could determine how strong it was before you landed so you would know where to land." The project continued after Anderson entered graduate school at Caltech (MS '59, PhD '62), where he studied geophysics and mathematics.

Upon his graduation from Caltech, Anderson was hired as a research fellow; he became an assistant professor in 1963, associate professor in 1964, and professor in 1968. Anderson was the Eleanor and John R. McMillan Professor from 1989 until his retirement in 2002.

From 1967 to 1989, Anderson was director of Caltech's Seismological Laboratory.

A fellow of the American Academy of Arts and Sciences, the National Academy of Sciences, and the American Philosophical Society, Anderson was also the recipient of the Emil Wiechert Medal of the German Geophysical Society, the Arthur L. Day Medal of the Geological Society of America, the Gold Medal of the Royal Astronomical Society, the William Bowie Medal of the American Geophysical Union, and the Crafoord Prize at the Royal Swedish Academy of Sciences.

In 1998, Anderson was awarded the National Medal of Science and was cited for his "immeasurable influence on the advancement of earth sciences over the past three decades nationally and internationally."

A full obituary will be posted at a later date.

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Tuesday, December 2, 2014
Guggenheim 101 (Lees-Kubota Lecture Hall) – Guggenheim Aeronautical Laboratory

PUSD: Annual Open Enrollment

Caltech Geologists Discover Ancient Buried Canyon in South Tibet

A team of researchers from Caltech and the China Earthquake Administration has discovered an ancient, deep canyon buried along the Yarlung Tsangpo River in south Tibet, north of the eastern end of the Himalayas. The geologists say that the ancient canyon—thousands of feet deep in places—effectively rules out a popular model used to explain how the massive and picturesque gorges of the Himalayas became so steep, so fast.

"I was extremely surprised when my colleagues, Jing Liu-Zeng and Dirk Scherler, showed me the evidence for this canyon in southern Tibet," says Jean-Philippe Avouac, the Earle C. Anthony Professor of Geology at Caltech. "When I first saw the data, I said, 'Wow!' It was amazing to see that the river once cut quite deeply into the Tibetan Plateau because it does not today. That was a big discovery, in my opinion." 

Geologists like Avouac and his colleagues, who are interested in tectonics—the study of the earth's surface and the way it changes—can use tools such as GPS and seismology to study crustal deformation that is taking place today. But if they are interested in studying changes that occurred millions of years ago, such tools are not useful because the activity has already happened. In those cases, rivers become a main source of information because they leave behind geomorphic signatures that geologists can interrogate to learn about the way those rivers once interacted with the land—helping them to pin down when the land changed and by how much, for example.

"In tectonics, we are always trying to use rivers to say something about uplift," Avouac says. "In this case, we used a paleocanyon that was carved by a river. It's a nice example where by recovering the geometry of the bottom of the canyon, we were able to say how much the range has moved up and when it started moving."

The team reports its findings in the current issue of Science.

Last year, civil engineers from the China Earthquake Administration collected cores by drilling into the valley floor at five locations along the Yarlung Tsangpo River. Shortly after, former Caltech graduate student Jing Liu-Zeng, who now works for that administration, returned to Caltech as a visiting associate and shared the core data with Avouac and Dirk Scherler, then a postdoc in Avouac's group. Scherler had previously worked in the far western Himalayas, where the Indus River has cut deeply into the Tibetan Plateau, and immediately recognized that the new data suggested the presence of a paleocanyon.

Liu-Zeng and Scherler analyzed the core data and found that at several locations there were sedimentary conglomerates, rounded gravel and larger rocks cemented together, that are associated with flowing rivers, until a depth of 800 meters or so, at which point the record clearly indicated bedrock. This suggested that the river once carved deeply into the plateau.

To establish when the river switched from incising bedrock to depositing sediments, they measured two isotopes, beryllium-10 and aluminum-26, in the lowest sediment layer. The isotopes are produced when rocks and sediment are exposed to cosmic rays at the surface and decay at different rates once buried, and so allowed the geologists to determine that the paleocanyon started to fill with sediment about 2.5 million years ago.

The researchers' reconstruction of the former valley floor showed that the slope of the river once increased gradually from the Gangetic Plain to the Tibetan Plateau, with no sudden changes, or knickpoints. Today, the river, like most others in the area, has a steep knickpoint where it meets the Himalayas, at a place known as the Namche Barwa massif. There, the uplift of the mountains is extremely rapid (on the order of 1 centimeter per year, whereas in other areas 5 millimeters per year is more typical) and the river drops by 2 kilometers in elevation as it flows through the famous Tsangpo Gorge, known by some as the Yarlung Tsangpo Grand Canyon because it is so deep and long.

Combining the depth and age of the paleocanyon with the geometry of the valley, the geologists surmised that the river existed in this location prior to about 3 million years ago, but at that time, it was not affected by the Himalayas. However, as the Indian and Eurasian plates continued to collide and the mountain range pushed northward, it began impinging on the river. Suddenly, about 2.5 million years ago, a rapidly uplifting section of the mountain range got in the river's way, damming it, and the canyon subsequently filled with sediment.

"This is the time when the Namche Barwa massif started to rise, and the gorge developed," says Scherler, one of two lead authors on the paper and now at the GFZ German Research Center for Geosciences in Potsdam, Germany.

That picture of the river and the Tibetan Plateau, which involves the river incising deeply into the plateau millions of years ago, differs quite a bit from the typically accepted geologic vision. Typically, geologists believe that when rivers start to incise into a plateau, they eat at the edges, slowly making their way into the plateau over time. However, the rivers flowing across the Himalayas all have strong knickpoints and have not incised much at all into the Tibetan Plateau. Therefore, the thought has been that the rapid uplift of the Himalayas has pushed the rivers back, effectively pinning them, so that they have not been able to make their way into the plateau. But that explanation does not work with the newly discovered paleocanyon.

The team's new hypothesis also rules out a model that has been around for about 15 years, called tectonic aneurysm, which suggests that the rapid uplift seen at the Namche Barwa massif was triggered by intense river incision. In tectonic aneurysm, a river cuts down through the earth's crust so fast that it causes the crust to heat up, making a nearby mountain range weaker and facilitating uplift.

The model is popular among geologists, and indeed Avouac himself published a modeling paper in 1996 that showed the viability of the mechanism. "But now we have discovered that the river was able to cut into the plateau way before the uplift happened," Avouac says, "and this shows that the tectonic aneurysm model was actually not at work here. The rapid uplift is not a response to river incision."

The other lead author on the paper, "Tectonic control of Yarlung Tsangpo Gorge revealed by a buried canyon in Southern Tibet," is Ping Wang of the State Key Laboratory of Earthquake Dynamics, in Beijing, China. Additional authors include Jürgen Mey, of the University of Potsdam, in Germany; and Yunda Zhang and Dingguo Shi of the Chengdu Engineering Corporation, in China. The work was supported by the National Natural Science Foundation of China, the State Key Laboratory for Earthquake Dynamics, and the Alexander von Humboldt Foundation. 

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Kimm Fesenmaier
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New Center Supports Data-Driven Research

With the advanced capabilities of today's computer technologies, researchers can now collect vast amounts of information with unprecedented speed. However, gathering information is only one half of a scientific discovery, as the data also need to be analyzed and interpreted. A new center on campus aims to hasten such data-driven discoveries by making expertise and advanced computational tools available to Caltech researchers in many disciplines within the sciences and the humanities.

The new Center for Data-Driven Discovery (CD3), which became operational this fall, is a hub for researchers to apply advanced data exploration and analysis tools to their work in fields such as biology, environmental science, physics, astronomy, chemistry, engineering, and the humanities.

The Caltech center will also complement the resources available at JPL's Center for Data Science and Technology, says director of CD3 and professor of astronomy George Djorgovski.

"Bringing together the research, technical expertise, and respective disciplines of the two centers to form this joint initiative creates a wonderful synergy that will allow us opportunities to explore and innovate new capabilities in data-driven science for many of our sponsors," adds Daniel Crichton, director of the Center for Data Science and Technology at JPL.

At the core of the Caltech center are staff members who specialize in both computational methodology and various domains of science, such as biology, chemistry, and physics. Faculty-led research groups from each of Caltech's six divisions and JPL will be able to collaborate with center staff to find new ways to get the most from their research data. Resources at CD3 will range from data storage and cataloguing that meet the highest "housekeeping" standards, to custom data-analysis methods that combine statistics with machine learning—the development of algorithms that can "learn" from data. The staff will also help develop new research projects that could benefit from large amounts of existing data.

"The volume, quality, and complexity of data are growing such that the tools that we used to use—on our desktops or even on serious computing machines—10 years ago are no longer adequate. These are not problems that can be solved by just buying a bigger computer or better software; we need to actually invent new methods that allow us to make discoveries from these data sets," says Djorgovski.

Rather than turning to off-the-shelf data-analysis methods, Caltech researchers can now collaborate with CD3 staff to develop new customized computational methods and tools that are specialized for their unique goals. For example, astronomers like Djorgovski can use data-driven computing in the development of new ways to quickly scan large digital sky surveys for rare or interesting targets, such as distant quasars or new kinds of supernova explosions—targets that can be examined more closely with telescopes, such as those at the W. M. Keck Observatory, he says.

Mary Kennedy, the Allen and Lenabelle Davis Professor of Biology and a coleader of CD3, says that the center will serve as a bridge between the laboratory-science and computer-science communities at Caltech. In addition to matching up Caltech faculty members with the expertise they will need to analyze their data, the center will also minimize the gap between those communities by providing educational opportunities for undergraduate and graduate students.

"Scientific development has moved so quickly that the education of most experimental scientists has not included the techniques one needs to synthesize or mine large data sets efficiently," Kennedy says. "Another way to say this is that 'domain' sciences—biology, engineering, astronomy, geology, chemistry, sociology, etc.—have developed in isolation from theoretical computer science and mathematics aimed at analysis of high-dimensional data. The goal of the new center is to provide a link between the two."

Work in Kennedy's laboratory focuses on understanding what takes place at the molecular level in the brain when neuronal synapses are altered to store information during learning. She says that methods and tools developed at the new center will assist her group in creating computer simulations that can help them understand how synapses are regulated by enzymes during learning.

"The ability to simulate molecular mechanisms in detail and then test predictions of the simulations with experiments will revolutionize our understanding of highly interconnected control mechanisms in cells," she says. "To some, this seems like science fiction, but it won't stay fictional for long. Caltech needs to lead in these endeavors."

Assistant Professor of Biology Mitchell Guttman says that the center will also be an asset to groups like his that are trying to make sense out of big sets of genomic data. "Biology is becoming a big-data science—genome sequences are available at an unprecedented pace. Whereas it took more than $1 billion to sequence the first genome, it now costs less than $1,000," he says. "Making sense of all this data is a challenge, but it is the future of biomedical research."

In his own work, Guttman studies the genetic code of lncRNAs, a new class of gene that he discovered, largely through computational methods like those available at the new center. "I am excited about the new CD3 center because it represents an opportunity to leverage the best ideas and approaches across disciplines to solve a major challenge in our own research," he says.

But the most valuable findings from the center could be those that stem not from a single project, but from the multidisciplinary collaborations that CD3 will enable, Djorgovski says. "To me, the most interesting outcome is to have successful methodology transfers between different fields—for example, to see if a solution developed in astronomy can be used in biology," he says.

In fact, one such crossover method has already been identified, says Matthew Graham, a computational scientist at the center. "One of the challenges in data-rich science is dealing with very heterogeneous data—data of different types from different instruments," says Graham. "Using the experience and the methods we developed in astronomy for the Virtual Observatory, I worked with biologists to develop a smart data-management system for a collection of expression and gene-integration data for genetic lines in zebrafish. We are now starting a project along similar methodology transfer lines with Professor Barbara Wold's group on RNA genomics."

And, through the discovery of more tools and methods like these, "the center could really develop new projects that bridge the boundaries between different traditional fields through new collaborations," Djorgovski says.

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