Berkeley Seismological Laboratory, University of California, Berkeley
Barbara A. Romanowicz was awarded the 2009 Inge Lehmann Medal at the AGU Fall Meeting Honors Ceremony, held on 16 December 2009 in San Francisco, Calif. The medal is for “out-standing contributions to the understanding of the structure, composition, and dynamics of the Earth’s mantle and core.”
It is my pleasure to introduce Barbara Romanowicz as the seventh recipient of the AGU Inge Lehmann Medal. Barbara’s work covers the full span of seismological studies from the crust to the inner core—not unlike Inge Lehmann’s. Barbara’s transformational contributions come from her investigations of attenuation (Q) in the Earth and, in particular, its lateral variations. This is an enormously difficult research area, since studies of attenuation require measurements of amplitude, and amplitudes, unlike the phase, depend on the details of the laterally varying structure. Barbara’s studies of lateral variations in attenuation began 20 years ago. In 1994, she discovered the pattern of attenuation in the transition zone and its correlation of low-Q with the distribution of hot spots. More recently, she developed a new three-dimensional (3-D) model of Q and pointed out the correlation of occurrence of superplumes in the lower mantle and attenuation in the transition zone.
The other area of Barbara’s fundamental contributions concerns application of asymptotic properties of normal modes to studies of lateral heterogeneity. Following early theoretical developments, she molded it into a tool used to obtain 3-D seismic velocity models. Her models of lateral heterogeneity have improved in the radial and horizontal resolution and are among those most frequently cited. Her work has now expanded to inversion for anisotropy, on both global and regional scales. She published a series of studies on the structure of the inner core, particularly its anisotropy. Most recently, she observed a change in the PKiKP amplitude over a period of 10 years, attributed to short-wavelength topography on the inner core boundary; differential rotation is one possible explanation.
The “Earth’s hum” is a beautiful example of coupling between the atmosphere, oceans, and solid Earth. Winds cause ocean waves that in turn excite free oscillations of the Earth observed in a range of periods from 200 to 500 seconds. Barbara was the first to locate the regions of the oceans where most of the excitation occurs: the North Pacific in winter and Southern Ocean in summer.
While Barbara’s research accomplishments are remarkable and should be sufficient for awarding her a medal, a description of her career would be incomplete without mentioning her contributions to the seismological infrastructure. A very major early effort was the establishment of a global network called Geoscope; with the first stations installed in 1982–1983, this effort preceded the Global Seismographic Network initiative of the Incorporated Research Institutions for Seismology (IRIS). Geoscope fills in vital locations in global coverage and produces excellent data, available to all. Not the least is her role in bringing back to eminence the seismographic network, and seismology in general, at University of California, Berkeley. As the director of the Seismological Laboratory for nearly 20 years, she has developed a number of new programs not only in broadband seismology but also in geodesy. She is leading the effort to establish the Cooperative Institute for Dynamic Earth Research (CIDER), intended to build a new, interdisciplinary approach to solving complex problems in Earth sciences.
In my opinion, Barbara is the most outstanding woman seismologist after Inge Lehmann. I believe it is most appropriate for AGU to award her the medal named after her predecessor.
—ADAM M. DZIEWONSKI, Harvard University, Cambridge, Mass.
Thank you, Adam, for your generous and flattering introduction. Thanks to AGU for deeming me worthy of this honor, and to my graduate students, postdocs, and collaborators, who share this award with me today.
Studies of the Earth’s mantle and core span several sections of AGU. I feel fortunate to be awarded the Inge Lehmann Medal this year, as I know there is a long waiting list of highly deserving colleagues.
Many roads lead to Rome, and a variety of paths lead to becoming a seismologist. In my case, as in many others’, it happened quite by chance. Not unlike Inge Lehmann, my training was in mathematics. After finishing my bachelor’s degree, I happened upon a poster advertising a master’s program in fundamental astronomy, including 2 weeks of training at the Observatoire du Pic du Midi, in the high Pyrenees. At that time, I would have jumped on any opportunity to leave the city and climb mountains.
This led me to the calculation of orbits of spacecraft around the Earth and the Moon that are affected by perturbations in the gravitational field. This was not long after the discovery of lunar “mascons” and when the first high-order descriptions of the Earth’s geopotential from satellite measurements were being produced. For me, it was the first encounter with the study of the Earth’s interior. This ultimately led me to the Institut de Physique du Globe de Paris (IPG) to work toward a Ph.D. with Kurt Lambeck, on the inversion of gravity data. One day I wandered onto the seismology floor at IPG and found Georges Poupinet displaying colorful global maps of seismic travel time anomalies—these were precursors of seismic tomography—and I soon discovered that seismology provides far better constraints on deep-Earth structure than gravity. Thirty years later, I still enjoy seismology as my primary research tool.
I am grateful to Kurt Lambeck for getting me off to a good start, and to Claude Allègre for making IPG a stimulating research environment and for entrusting me with the Geoscope program. I had the privilege of having Kei Aki as a postdoc advisor and Adam Dziewonski as a partner in several rewarding initiatives over the years, starting with the International Federation of Digital Seismograph Networks, the International Ocean Network, and more recently, CIDER. The University of California, Berkeley has been a wonderful place to work for the past 18 years.
I thank my parents for broadening my horizons by bringing me up bilingual and for having the foresight to send me to England at the age of 10, anticipating that a fluent knowledge of English would facilitate whatever career I chose in today’s world.
Last but not least, I wish to thank my husband, Mark Jonikas, for his infinite patience and support, and my children, Martin and Magda, for their cooperation by having slept through the night from the age of 2 months, by having spared us any teenage crises, and by having turned into fine young adults, both now starting their own post-Ph.D. careers in science.
—BARBARA A. ROMANOWICZ, Berkeley Seismological Laboratory, University of California, Berkeley