IRIS/SSA Distinguished Lecture Series 2005 Season

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1 IRIS/SSA Distinguished Lecture Series 2005 Season The Incorporated Research Institutions for Seismology (IRIS) and the Seismological Society of America (SSA) are pleased to announce the selection of two experienced speakers from the Earth science research community for the third annual IRIS/SSA Distinguished Lectures Series. The lecturers will be presenting talks aimed at general audiences during The speakers and their topics are: Dr. Susan Hough, U.S. Geological Survey: The Very Long Reach of Very Large Earthquakes Dr. Michael Wysession, Washington University: Earthquakes, Tsunamis and a Modern Journey to the Center of the Earth The Lecture Series is seeking museum, university, and other venues for this season s lecturers. General arrangements, including publicity, will be coordinated between IRIS, SSA, and the sponsoring venue. The desired audience size is 300 or more. IRIS and SSA will provide speaker travel costs and may also provide accompanying seismology displays and other outreach materials if feasible. For more information, please visit Or contact: John Taber - taber@iris.edu Education & Outreach Program Manager IRIS Consortium 1200 New York Ave. NW, Suite 800 Washington, DC

2 The Very Long Reach of Very Large Earthquakes Dr. Susan Hough, U.S. Geological Survey When the magnitude 7.3 Landers earthquake struck in 1992 in the desert north of Palm Springs, the earthquake map of the state of California lit up like a Christmas tree. These unprecedented observations led scientists to the discovery of remotely triggered earthquakes earthquakes that follow large earthquakes but happen at much greater distances than the nearby aftershocks that are almost always associated with a big earthquake. This voyage of scientific discovery of remotely triggered earthquakes is part of a fundamental change in the way that scientists view earthquakes. Once thought to be isolated in both time and space, the reach of large earthquakes their impact on not only the surrounding region but also the planet as a whole is now known to be far longer, and far more interesting, than scientists realized just a few years ago. Early studies linked the occurrence of these events to the stress changes caused by passing seismic waves. Scientists suggested the analogy of shaking a soda can to explain how earthquake waves might raise pressure in underground fluids, and thereby trigger other earthquakes. The initial view of remotely triggered earthquakes has expanded since the early 1990s as scientists have learned more about where and why these earthquakes happen. Looking back at accounts of earthquakes that struck before seismometers were invented, one finds compelling evidence that remotely triggered earthquakes occurred in the past, for example during the New Madrid earthquake sequence in Missouri. The largest historic earthquake in New England may have also been triggered by the great Lisbon earthquake of These studies reveal that remotely triggered earthquakes occur commonly, and not just in volcanic regions where they were first observed a result that requires earlier theories to be revised, or at the very least, expanded. In California, a new hypothesis further suggests that large earthquakes may have had a very long reach through time as well as space, in the form of petroglyphs that may in fact chronicle some of California s pre-historic earthquakes and volcanic events. Thus have scientists arrived at new paradigms for not only earthquake interactions the interaction of earthquakes with each other but also the interaction of earthquakes with human cultures, past and present.

3 Dr. Susan Elizabeth Hough, Seismologist U.S. Geological Survey, Pasadena Education Ph.D., Scripps Institution of Oceanography, UC San Diego, Earth Sciences, 1987 A.B., University of California, Berkeley, Geophysics, with honors, 1982 Professional Positions Seismologist, Branch of Seismology, U.S. Geological Survey, Pasadena, California, 1992-Present Editor in Chief, Seismological Research Letters, 2001-Present Dr. Susan Hough is currently a seismologist with the U.S. Geological Survey in Pasadena and Editor-in-Chief of Seismological Research Letters. After completing her Ph.D. in 1987, she worked at Lamont-Doherty Earth Observatory of Columbia University in New York for 4 years before moving back to California. Her research interests include the nature of ground shaking produced by large earthquakes, historic earthquakes (the New Madrid earthquakes in particular), earthquakes and earthquake hazard in India, and remotely triggered earthquakes. Dr. Hough has published two books on earthquake science for a non-specialist audience: Earthshaking Science: What we know (and don t know) about earthquakes, and Finding Fault in California: An earthquake tourist s guide. A third book, Elastic Rebound: Past and future earthquakes on an urban planet (Susan Hough and Roger Bilham, a previous IRIS/SSA distinguished lecturer), is scheduled for publication in She has additionally published several feature articles in Natural History Magazine and American Scientist. Books Earthshaking Science: What we know (and don t know) about earthquakes, Princeton University Press, 272 pp, Finding Fault in California: An earthquake tourist s guide, Mountain Press Publishers, 268 pp, Elastic Rebound: Past and future earthquakes on an urban planet (Susan Hough and Roger Bilham), Oxford Press, expected publication date 2005.

4 Selected General Interest Publications Hough, S.E., The aftershocks that weren't, Natural History Magazine, 64-69, March, Hough, S.E. and R. Bilham, Shaken to the core, Natural History Magazine, 42-48, February, Ben-Avraham, Z. and S.E. Hough, Promised Land, Natural History Magazine, 44-49, October, Hough, S.E., Writing on the Walls, American Scientist, in press, August, Selected Peer-Reviewed Publications Hough, S.E., R.D. Borcherdt, P.A. Friberg, R. Busby, E.H. Field, and K.H. Jacob. Sediment-induced amplification and the collapse of the Nimitz Freeway, Nature, 344, , Hough, S.E., Earthquakes in the Los Angeles Metropolitan region: A possible fractal distribution of rupture size, Science, 267, , Hough, S.E., J.G. Armbruster, L. Seeber, and J.F. Hough, On the modified Mercalli intensities and magnitudes of the New Madrid earthquakes, J. Geophysical Research 105, 23, , Hough, S.E., Triggered earthquakes and the New Madrid, central U.S. earthquake sequence, Bulletin Seismological Society America, 91, , Hough, S.E. and H. Kanamori, Source properties of earthquakes near the Salton Sea triggered by the 10/16/1999 M7.1 Hector Mine earthquake, Bull. Seismological Society of America, 92, , Mueller, K., S.E. Hough, and R. Bilham, Analysing the New Madrid earthquakes with recent instrumentally recorded aftershocks, Nature, 429, , 2004.

5 Earthquakes, Tsunamis, and a Modern Journey to the Center of the Earth Dr. Michael Wysession, Washington University As the recent earthquake and tsunami in Sumatra showed, we live on the surface of this vibrant planet by geological consent. This earthquake released more energy than the energy contained in the nuclear arsenals of all countries combined. However, geological disasters are not limited to places on the other side of the world. Earthquakes and tsunamis pose continuous threats in many parts of the United States, even many places that are often thought to be safe. However, geologists are also fascinated by earthquakes because they give us an opportunity to discover what the inside of our planet is made of. We know more about the structure of our galaxy and the details of living cells than we do about what is 10 feet beneath us. The reason is simple. Light does not pass through rock. However, seismologists are working rapidly to improve our vision of Earth s interior. Using the seismic waves from earthquakes and explosions, seismologists are now making exciting three-dimensional pictures of Earth s interior. These pictures are very important for many reasons: this is how we find natural resources like petroleum, and how we monitor the size and location of any nuclear tests. Perhaps even more importantly, these images help satisfy our basic human need for discovery of the world we live in. What are planets made of? How and why do they form? What will happen to Earth in the future? These are the kinds of questions that Professor Wysession will address through a tour of Earth s interior, crust to core. This Journey to the Center of the Earth will reveal aspects of our planet that are too strange for even Jules Verne or Hollywood to have imagined.

6 Dr. Michael E. Wysession, Associate Professor Washington University, St. Louis, Missouri Education Ph.D., Northwestern University, Geophysics, 1991 Sc.B., Brown University, Geophysics, 1984 Positions Held Associate Professor, Washington University, Assistant Professor, Washington University, High School Math and Physics Teacher, Staten Island Academy, Dr. Michael Wysession has established himself as a world leader in the area of seismology and geophysical education. He has developed several means of using the seismic waves from earthquakes to see into the Earth and create three-dimensional pictures of Earth s interior. These images help us to understand what the Earth is made of and how it evolves over time. An important part of the focus of Professor Wysession s research has been the complex boundary region between the solid rock of Earth s mantle and the liquid iron of Earth s core. Some of these investigations have been carried out using seismic information from arrays of seismometers that he has deployed across America. The results show that our planet is in constant internal motion, carrying heat from the deep interior up to the surface like a continual conveyor belt. Professor Wysession is also a leader in the area of geoscience education. He is the lead author of Prentice Hall s 9 th grade physical science book, Physical Science: Concepts in Action. He has also supervised, in the role of primary book writer, several other secondary education textbooks such as Prentice Hall s 9 th grade text Earth Science, and their 6 th grade-level texts Earth s Interior, Earth s Changing Surface, and Earth s Waters. Professor Wysession regularly works with secondary education science teachers at teacher-training workshops. At a more advanced level, he is the coauthor of Introduction to Seismology, Earthquakes, and Earth Structure, a leading graduate-level textbook used in geophysics classes around the world. He also constructed the first computergenerated animation of how seismic waves propagate within the Earth from an earthquake, creating a 20-minute movie that is used in many high school and college classrooms. Professor Wysession has also written about the deep Earth in several general-audience publications such as Scientific American, American Scientist, and Earth magazine. Professor Wysession s research and educational efforts have been recognized through several fellowships and awards. He has received a Science and Engineering Fellowship from the David and Lucille Packard Foundation, and a National Science Foundation Presidential Faculty Fellowship, awarded by

7 President Clinton. Both were awarded to only 20 American scientists across all disciplines. He has received fellowships from the Kemper and Lily foundations to enhance his teaching and has also been given the Innovation Award of the St. Louis Science Academy, and the Distinguished Faculty Award of Washington University. Books Gurnis, M., M. Wysession, E. Knittle, and B. Buffett, eds., The Core-Mantle Boundary Region, AGU, Washington, D.C., 334 pp., Stein, S. and M. E. Wysession, An Introduction to Seismology, Earthquakes, and Earth Structure, Blackwell Scientific, 498 pp., Wysession, M.E., D. Frank, and S. Yancopoulis, Physical Science: Concepts in Action, Prentice-Hall, 925 pp., Selected General Interest Publications Wysession, M. E., Plate tectonics: The restless Earth, in Scientific American Triumph of Discovery: Celebrating 150 Years of Innovation, pp , Wysession, M. E., The Inner Workings of the Earth, American Scientist, 83, , Wysession, M. E., Seismic images of the core-mantle boundary, GSA Today, 5, 237, , , Wysession, M. E., Journey to the Center of the Earth, Earth Magazine, 5, 46-49, Wysession, M. E., and S. Baker, An educational animation of the propagation of earthquake-generated seismic shear waves across the mantle, J. Geoscience Education, 50, , Selected Peer-Reviewed Publications Kuo, B. Y., D. W. Forsyth and M. E. Wysession, Lateral heterogeneity and azimuthal anisotropy in the North Atlantic determined from SS-S differential travel times, J. Geophys. Res., 92, , Wysession, M. E., E. A. Okal and C. R. Bina, The structure of the core-mantle boundary from diffracted waves, J. Geophys. Res., 97, , Wysession, M. E., A window on the core, Nature, 361, , Wysession, M. E., L. Bartkó, and J. Wilson, Mapping the lowermost mantle

8 using core-reflected shear waves, J. Geophys. Res., 99, 13,667-13,684, Wysession, M. E., Continents of the core, Nature, 381, , Wysession, M. E., Large-scale structure at the core-mantle boundary from core-diffracted waves, Nature, 382, , Wysession, M. E., A. Langenhorst, K. M. Fischer, G. I. Al-eqabi, P. J. Shore, M. J. Fouch, and T. J. Clarke, Mantle flow inferred from lateral variations in compressional/shear velocities at the base of the mantle, Science, 284, , Valenzuela, R. W., M. E. Wysession, M. O. Neustadt, and J. L. Butler, Lateral variations at the base of the mantle from profiles of digital Sdiff data, J. Geophys. Res., 105, , Fisher, J. L., M. E. Wysession, K. M. Fischer, Small-scale lateral variations in D'' attenuation and velocity structure, Geophys. Res. Lett., Vol. 30 No. 8, /2002GL016179, 26 April 2003.