Arizona State University
Vibrations From the Deep: Deciphering the Birth and Death of Earth’s Surface
While the most fundamental feature of interiors of large planetary bodies is layering/stratification, the creation and destruction of Earth’s outermost rigid shell at mid-ocean ridges and subduction zones, mountain building, earthquakes, and volcanic activity, all point to dynamical processes within the interior that must certainly go far beyond simple internal layering. However, Earth’s deep interior is predominantly inaccessible, since one can only drill several miles deep, and volcanic activity only very rarely involves material thought to originate from below a couple hundred miles or so. We are thus left with the question: how can the rest of the interior, nearly 4000 miles of material down to the center, be confidently interrogated? And furthermore, can we characterize deep structure and processes at a level that reveals the connection between the making of Earth’s surface and its interior?
Using seismic imaging techniques, we are now getting glimpses of exotic internal structures at a variety of spatial scale lengths: from several kilometers to 1000’s of km. While there is certainly so much that lies before us awaiting discovery, we are now seeing connections between hot spot volcanoes and partially molten material half way to Earth’s center at the base of the mantle. We are also detecting deep mantle seismic wave reflections (or “echoes”) off of former oceanic crust and lithospheric material, confirming the hypothesis that some tectonic plates submerge into the interior. Presently or in the near future, the National Science Foundation funded EarthScope USArray will have over 100 seismic motion detectors marching across your state. This program will continue the advancement of our understanding of the symbiotic relationship between Earth’s surface and interior, because there have not high numbers of recorders in a given area before. My presentation will show recent results from a variety of experiments, highlighting those that help to decipher Earth’s enigmatic and unreachable interior.
About Dr. Garnero
Education
Ph.D., California Institute of Technology, 1994
A.B., University of California, Berkeley, 1986
Positions Held
Associate Professor, Arizona State University, Tempe, AZ, June 2005-Present
Assistant Professor, Arizona State University, Tempe, AZ, Jan 1999-May 2005
Assistant Researcher, University of California, Berkeley, July 1997-Dec 1998
Postdoctoral Researcher, University of California, Santa Cruz, June 1996-July 1997
NSF Postdoctoral Researcher, University of California, Santa Cruz, June 1994-June 1996
Staff Seismologist, Woodward-Clyde Consultants, Oct 1989-Dec 1991
Dr. Ed Garnero is currently an Associate Professor in the Department of Geological Sciences at Arizona State University in Tempe, Arizona. His research interests have centered on understanding the relationship between the structure and dynamics of Earth’s deep interior and Earth’s surface, but include analyses of seismic wave propagation, and seismic interrogation of the birth and death of features that exchange mass and heat between the surface and the interior, such as hot plumes and cold descending oceanic lithosphere. The detailed nature of Earth’s interior, particularly up until recently, can be considered only poorly known. Thus seismic methods that provide information on dynamical processes in the interior help us better understand the forces and processes that shape the surface that we live upon.
Professor Garnero has devoted significant resources towards teaching geological sciences to entry level students, as well as the lay population. This has resulted in multiple “Favorite Professor” citations from campus-wide student polls at one of the nation’s largest public universities, as well as a Distinguished Faculty citation from ASU’s Department of Geological Sciences. In 2004, he was awarded a Last Lecturer Series citation, in which only 3 of ASU’s over 2100 professors are yearly selected by students to give what would be their last lecture ever. In the fall of 2005, Dr. Garnero was named an ASU Faculty Exemplar, in which the ASU President selects newly tenured faculty as exemplars of “the finest teacher-scholars” of the university. Dr. Garnero continues to receive the department’s highest teaching evaluations for their 230 student entry level geology 101 course, owing to a combination of his dynamic lecturing style, a multimedia approach in which all class resources are openly shared online with students, and dynamic class experiments/presentations which include performances on his electric bass with student compositions of “geology songs”. Garnero emphasizes the process of “discovery” in his teaching (and research); this enhances his conveyance of research excitement, whether in general public lectures or the classroom. Bringing discovery into the classroom was a focal point of his NSF Career Award, one of NSF’s most prestigious awards across all disciplines that support early career-development activities of teacher-scholars that most effectively integrate research and teaching. His work has been highlighted in various lay magazines (e.g., Science News), as well as television (e.g., National Geographic’s Naked Science episode on The Earth’s Core).
Selected Recent Publications
Rost, S., E.J. Garnero, Q. Williams and M. Manga, Seismic constraints on a possible plume root at the core-mantle boundary, Nature, 435, 666-669, DOI: 10.1038/nature03620, 2005.
Garnero, E.J., Maupin, V., Lay, T., and M.J. Fouch, Variable azimuthal anisotropy in Earth's lowermost mantle, Science, 306 (5694), 259-61, DOI: 10.1126/science.11034112004.
Garnero, E.J., A new paradigm for Earth's core-mantle boundary, Science, 304 (5694), 834-836, doi: 10.1126/science.1097849, 2004.
Buffett, B.A., E.J. Garnero, and R. Jeanloz, Science, 290, 1338-1342, DOI: 10.1126/science.290.5495.1338, 2000.
Garnero, E.J., and R. Jeanloz, Earth's enigmatic interface, Science, 289, 70-71, DOI: 10.1126/science.289.5476.70, 2000.
Garnero, E.J., Heterogeneity of the lowermost mantle, Ann. Rev. Earth Planetary Sci., 28, 509-37, 2000.
Lay, T., Q. Williams, and E.J. Garnero, The core-mantle boundary layer and deep earth dynamics, Nature, 392, 461-468, 1998.
Williams, Q., J.S. Revenaugh, E.J. Garnero, A correlation between ultra-low basal velocities in the mantle and hot spots, Science, 281, 546-549, DOI: 10.1126/science.281.5376.546, 1998.
Russell, S., T. Lay, and E.J. Garnero, Seismic evidence for small-scale dynamics in the lowermost mantle at the root of the Hawaiian hotspot, Nature, 369, 255-257, 1998.
Williams, Q., and E.J. Garnero, Seismic evidence for partial melt at the base of Earth's mantle, Science, 273, 1528-1530, 1996.
