James Gaherty

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	James Gaherty Doherty Research Scientist Seismology-Geology-Tectonophysics	Lamont -Doherty Earth Observatory 61 Route 9W Palisades, NY 10964 email (spam-resistant): phone (845) 365-8450 fax (845) 365-8150 www.ldeo.columbia.edu/~gaherty

EDUCATION	Ph.D. Geophysics, Massachusetts Institute of Technology, 1995 M.S. Geology, University of Michigan, 1990 B.S. Geophysics, Brown University, 1986
RESEARCH	The Earth has a remarkably active interior, and this internal activity is responsible for much of the deformation and dynamism that is observed on the Earth's surface. This includes short-term phenomena such as earthquakes and volcanoes, as well as the more subtle but equally impressive long-term deformation and tectonism in regions such as the Himalaya and the western US. My goal is to understand the processes responsible for such surface deformation by studying the structure and geodynamics of the Earth's crust and mantle. In general, the Earth's internal activity is driven by mantle convection, the mechanism by which the Earth eliminates excess heat. Seismic imaging provides a tool to investigate subtle changes in the physical properties of mantle rock that are associated with convection: fast and slow seismic wavespeeds correspond to regions of low and high temperatures which drive convective currents,discontinuities mark compositional and mechanical variations that modulate the flow, and seismic anisotropy maps the flow history of the rocks. By imaging variations in such properties, I hope to gain a better understanding of the dynamics of the mantle and crust and its role in shaping surface processes.
PROJECTS	CANOE -- The CAnadian NOrthwest seismic Experiment SCOOBA -- Sea of COrtez Ocean-Bottom Array Seismic Experiment EarthScope -- Mapping upper mantle anisotropy beneath the western US: toward an integrated seismic and geodynamic analysis of crust-mantle coupling -- web page coming soon.
LINKS	EarthScope Project Incorporated Research Institutions in Seismology (IRIS) Lamont Cooperative Seismic Network National Ocean Bottom Seismograph Instrumentation Pool (OBSIP)
SELECTED PUBLICATIONS	Delorey, A.A., R.A. Dunn, and J.B. Gaherty, Surface Wave Tomography of the Upper Mantle Beneath the Reykjanes Ridge with Implications for Ridge-Hotspot Interaction, J. Geophys. Res ., 112, B08313, doi:10.1029/2006JB004785, 2007. (reprint) Gaherty, J.B. and R.A. Dunn, Evaluating hotspot-ridge interaction in the Atlantic from regional-scale seismic observations, Geochem. Geophys. Geosyst., 8, Q05006, doi:10.1029/2006GC001533, 2007. (reprint) Gu, Y.J., S.C. Webb, A. Lerner-Lam, and J.B. Gaherty, Upper-mantle structure beneath the eastern Pacific Ocean ridges, J. Geophys. Res . 110 , B06305, doi:10.1029/2004JB003381, 2005. (reprint) Gaherty, J.B., D. Lizarralde, J.A. Collins, G. Hirth, and S. Kim, Mantle deformation during slow seafloor spreading constrained by observations of seismic anisotropy in the western Atlantic, Earth Planet. Sci. Lett., 228, 255-265, 2004. (reprint) Lizarralde, D., J.B. Gaherty, J.A. Collins, G. Hirth, and S. Kim, Spreading-rate dependence of melt extraction at mid-ocean ridges from far-offset seismic data, Nature, 432, 744-747, 2004. (reprint) (supplemental information) Gaherty, J.B., A surface-wave analysis of seismic anisotropy beneath eastern North America, Geophys. J. Int., 158, 1053-1066, 2004. (color reprint) (greyscale reprint) Gaherty, J.B., Seismic evidence for hotspot-induced buoyant flow beneath the Reykjanes Ridge, Science, 293, 1645-1647, 2001. (reprint from sciencemag.org)