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HARDING, ALISTAIR

Full Research Geophysicist

Degrees:

• B.A., University of Cambridge, England
• M.A., University of Cambridge, England
• Ph.D., University of Cambridge, England

Research Interests:

• Rifting of continental lithosphere
• Ridge Crest Processes
• Oceanic Crustal structure
• Three-D tomographic study of the Clipperton Transform
• Modeling and evolution of Moho at oceanic ridges
• Reflection seismic processing

Courses Recently Taught:

• SIO182A: Envr & Exploration Geophys A
• SIO182B: Envr & Exploration Geophys B

Mentoring:

• Dingler, Allison (Graduate; 2001-2007)
• Sutherland, Fiona (Graduate; 2000-2006)
• Hallenborg, Eric (Graduate; 1997-2003)
• Bazin, Sara (Graduate; 1994-2000)
• van Avendonk, Harmanus (Graduate; 1993-1998)
• Posiolova, Liliya (Graduate; 1991-1999)
• Babcock, Jeffrey (Graduate; 1990-1997)
• Tolstoy, Maria (Graduate; 1988-1994)
• Kappus, Mary (Graduate; 1987-1991)
• Kent, Graham (Graduate; 1987-1992)

Nedimovic, M. R., S. M. Carbotte, J. B Diebold, A. J. Harding, J. P. Canales, and G. M. Kent, Upper crustal evolution across the Juan de Fuca ridge flanks, Geochem. Geophys. Geosyst., 9, Q09006, doi:10.1029/2008GC002085, 2008.

Carbotte, S. M., M. R. Nedimoviç, J. P Canales, G. M. Kent, A. J. Harding, and M. Marjanoviç, Variable crustal structure along the Juan de Fuca Ridge: Influence of on-axis hot spots and absolute plate motions, Geochem. Geophys. Geosyst., 9, Q08001, doi:10.1029/2007GC001922, 2008.

Lizarralde, D., G. J. Axen, H. E. Brown, J. M. Fletcher, A. Gonzalez-Fernadez, A. J. Harding, W. S. Holbrook, G. M. Kent, P. Paramo, F. Sutherland and P. J. Umhoefer, Variations in styles of rifting in the Gulf of California, Nature, 466-469, doi:10.1038/nature06035, 2007.

Jacobs, A. M., A. J. Harding and G. M. Kent, Axial crustal structure of the Lau back-arc basin from velocity modeling of multichannel seismic data, Ear. Sci. Planet. Lett., 259, 239-255, doi:10.1016/j.epsl.2007.04.021, 2007.

Van Ark, E. M., R. S. Detrick, J. P. Canales, A. J. Harding, G. M. Kent, M. R. Nedimovic, W. S. D. Wilcock, J. B. Diebold and J. M. Babcock, Seismic structure of the Endeavour Segment, Juan de Fuca Ridge: Correlations with seismicity and hydrothermal activity, J. Geophys. Res., 112, B02401 (1-22 pp.), doi:10.1029/2005JB004210, 2007.

S. C. Singh, A. J. Harding, G. M. Kent, M. C. Sinha, V. Combier, S. Bazin, C. H. Tong, J. W. Pye, P. J. Barton, R. W. Hobbs, R. S. White and J. A. Orcutt, Seismic reflection images of the Moho underlying melt sills at the East Pacific Rise, Nature, 442, 287-290, 2006.

Canales, J. P., Singh, S. C.; Detrick, R. S.; Carbotte, S. M.; Harding, A.; Kent, G. M.; Diebold, J. B.; Babcock, J.; Nedimovic, M. R.,Seismic evidence for variations in axial magma chamber properties along the southern Juan de Fuca Ridge, Earth Planet. Sci. Lett., 246, 353-366, 2006.

J. P. Canales, R. S. Detrick, S. M. Carbotte, G. M. Kent, J. B. Diebold, A. Harding, J. Babcock, M. R. Nedimovic, and E. van Ark, Upper crustal structure and axial topography at intermediate spreading ridges: Seismic constraints from the southern Juan de Fuca Ridge, J. Geophys. Res., 110, doi:10.1029/2005JB003630, 2005.

S. M. Carbotte, R. S. Detrick, A. Harding, J. P. Canales, J. Babcock, G. Kent, E. Van Ark, M. Nedimovic, J. Diebold, Rift topography linked to magmatism at the intermediate spreading Juan de Fuca Ridge, Geology, 34, 209-212, 2005.

M. R. Nedimovic, Suzanne M. Carbotte, A. J. Harding, R. S. Detrick, J. P. Canales, J. B. Diebold, G. M. Kent, M. Tischer and J. M. Babcock, Frozen magma lenses below the oceanic crust, Nature 436, 1149-1152, 2005.

C. H. Tong, C. Lana, R. S. White, M. R. Warner and ARAD Working Group,Subsurface tectonic structure between overlapping mid-ocean ridge segments, Geology, 33, 409-412, 2005.

G.M. Kent, J. M. Babcock, N. W. Driscoll, A. J. Harding, J. A. Dingler, G. G. Seitz, J. V. Gardner, L. A. Mayer, C. R. Goldman, A. C. Heyvaert, R. C. Richards, R. Karlin, P. T. Gayes, and C. W. Morgan, A 60ka record of extension across the western boundary of the basin and range province: Slip-rate estimation from offset shorelines and a catastrophic slide beneath Lake Tahoe, Geology, 33, 365-368, 2005.

C.H. Tong, R.S. White, M.R. Warner,and the ARAD Working Group, Effects of tectonism and magmatism on crack structure in oceanic crust: A seismic anisotropy study,Geology, 32, 25-28, 2004.

Wilson, D. S., E. Hallenborg, , A. J. Harding, and G. M. Kent, “Data Report: Site Survey Results from Cruise EW9903, Proceedings of the Ocean Drilling Program, Initial Reports, 206, (04) 1-49, 2003.

Hallenborg, E., A. J. Harding, G. M. Kent, and D. S. Wilson, “Seismic structure of 15 Ma oceanic crust formed at an ultra-fast spreading East Pacific Rise: Evidence for kilometer-scale fracturing from dipping reflectors”, J. Geophys. Res., 108, EPM(11) 1-22, 2003.

Tong, C. H., P. J. Barton, R. S. White, M. C. Sinha, S. C. Singh, J. W. Pye, R. W. Hobbs, S. Bazin, A. J. Harding, G. M. Kent and J. A. Orcutt, Influence of enhanced melt supply on upper crustal structure at a mid-ocean ridge discontinuity: A three-dimensional seismic tomographic study of 9°N East Pacific Rise, J. Geophys Res., 108, EPM(2) 1-14, 2003.

Bazin, S., A. J. Harding, G. M. Kent, J. A. Orcutt, S. C. Singh, C. H. Tong, J. W. Pye, P. J. Barton, M. C. Sinha, R. S. White, R. W. Hobbs, and H. J. A. Van Avendonk, A three-dimensional study of a crustal low velocity region beneath the 9°03’N overlapping spreading center, Geophys. Res. Lett., 30, (11) 14, 2003.

Tong, C. H., J.W. Pye, P.J. Barton, R.S. White, M.C. Sinha, S.C. Singh, R.W. Hobbs, S. Bazin, A.J. Harding, G.M. Kent, and J.A. Orcutt, Asymmetric melt sills and upper crustal construction beneath overlapping ridge segments: Implications for the development of melt sills and ridge crests, Geology, 30, 83-86, 2002.

Lizarralde, D., G. J. Axen, J. M. Fletcher, A. Gonzalez-Fernandez, G. M. Kent, A. J. Harding, W. S. Holbrook, and P. J. Umhoefer, A Seismic and Geologic Study of Gulf of California Rifting and Magmatism, Margins Newsletter, 7, 1-5, 2001.

Hussenoeder, S. A., G. M. Kent, R. S. Detrick, H. Schouten, and A. J. Harding, Fine Scale seismic structure of young upper crust at 17° 20' S on the fast spreading East Pacific Rise, J. Geophys. Res. 107, EPM(2) 1-29, 2002.

Harding, A. J., Seismic Structure, in Encyclypedia of Ocean Sciences, ed. J. H. Steele, Academic Press, New York, 6pp, 2figs, 2001.

Bazin, S., A. J. Harding, G. M. Kent, J. A. Orcutt, C. H. Tong, J. W. Pye, S. C. Singh, P. J. Barton, M. C. Sinha, R. S. White, R.W. Hobbs, and H. J. A. Van Avendonk, Three-dimensional shallow crustal emplacement at the 9°03'N overlapping spreading center on the East Pacific Rise: Correlations between magnetization and tomographic images J. Geophys. Res.,106,16,101-16,117,2001.

Van Avendonk, H. J. A.; Harding, A. J.; Orcutt, J. A.; McClain, J. S., Contrast in crustal structure across the Clipperton transform fault from travel time tomography. J. Geophys. Res., 106, 10961-10981, 2001.

Van Avendonk, H. J. A., A. J. Harding, J. A. Orcutt, and W. S. Holbrook, Hybrid method for traveltime and raypath calculations, Geophysics, 66, 648-653, 2001.

Kent, G.M., S.C. Singh, A.J. Harding, M.C. Sinha, J.A. Orcutt, P.J. Barton, R.S. White, S. Bazin, R.W. Hobbs, C.H. Tong, and J.W. Pye, Evidence from three-dimensional seismic reflectivity images for enhanced melt supply beneath mid-ocean-ridge discontinuities. Nature, 406, 614-618, 2000.

Singh, S. C., M. C. Sinha, A. J. Harding, G. M. Kent, P. J. Barton, J. A. Orcutt, R. S. White, and R. W. Hobbs, Preliminary results are in from mid-ocean ridge three-dimensional seismic reflection survey, Eos, Trans. AGU, 80, 181 & 185, 1999.

Singh, S C, J. S. Collier, A. J. Harding, G. M. Kent, and J. A. Orcutt, Seismic evidence for a hydrothermal layer above the solid roof of the axial magma chamber at the southernEast Pacific Rise,Geology, 27,219-222, 1999.

Babcock, J. M., A. J. Harding, G. M. Kent, and J. A. Orcutt, An examination of along-axis variation of magma chamber width and crustal structure on the East Pacific Rise between 13° 30' N and 12° 20' N, J. Geophys. Res.103,30451-30467, 1998.

van Avendonk, H., A. J. Harding, J. A. Orcutt, and J. S. McClain, A two-dimensional tomographic inversion of the Clipperton Transform Fault, J. Geophys. Res., 103, 17885-17899, 1998.

Singh, S. C., G. M. Kent, J. S. Collier, A. J. Harding and J. A. Orcutt, Melt to mush variations in crustal magma properties along the ridge crest at the southern East Pacific Rise, Nature, 394, 874-878, 1998.

Bazin, S., H. van Avendonk, A. J. Harding, J. A. Orcutt, J. P. Canales, and R. S. Detrick, Crustal structure of the flanks of the East Pacific Rise: implications for overlapping spreading centers, Geophys. Res. Lett., 25, 2213-2216, 1998.

Canales, J.P., R. S. Detrick, S. Bazin, A. J. Harding, and J. A. Orcutt, Off-axis crustal thickness across and along the East Pacific Rise within the MELT area. Science, 280, 1218-1221, 1998.

Forsyth, D. W., D. S. Scheirer, S. C. Webb, L. M. Dorman, J. A. Orcutt, A. J. Harding, D. K. Blackman, J. Phipps Morgan, R. S. Detrick, Y. Shen, C. J. Wolfe, J. P. Canales, D. R. Toomey, A. F. Sheehan, S. C. Solomon, and W. S. D. Wilcock, Imaging the deep seismic structure beneath a mid-ocean ridge: the MELT Experiment. Science, 280, 1215-1218, 1998.

Kent, G. M., A. J. Harding S. Singh, M. Sinha, P. Barton, J. Orcutt, R. White and ARAD group, The ARAD 3-D seismic experiment: A detailed reflection and tomographic investigation of the 9° 03' N Overlapping Spreading Center, East Pacific Rise, InterRidge News, 7, 33-39, 1998. Article

Harding, A. J., M .A. H. Hedlin, and J. A. Orcutt, Migration of backscatter data from the Mid-Atlantic Ridge. J. Acoust. Soc. Am., 103, 1787-1803, 1998.

Begnaud, M.L., J. S. McClain, G. A. Barth, J. A. Orcutt, and A. J. Harding,Velocity structure from forward modeling of the eastern ridge-transform intersection area of the Clipperton Fracture Zone, East Pacific Rise. J. Geophys. Res, 102, 7803-7820, 1997.

Tolstoy M., A. J. Harding, J. A. Orcutt and the TERA group, Deepening of the axial magma chamber on the Southern East Pacific Rise toward the Garrett Fracture Zone, J. Geophys. Res., 102, .3097-3108, 1997.

Hussenoeder, S. A., J. A. Collins, G. M. Kent, R. S. Detrick, and the TERA group (A. J. Harding & J. A. Orcutt), Seismic analysis of the axial magma chamber reflector along the southern East Pacific Rise from conventional reflection profiling, J. Geophys. Res., 101, 22087-22105, 1996.

Kent, G. M., I. I. Kim, A. J. Harding, R. S. Detrick, and J. A. Orcutt, Suppression of sea-floor-scattered energy using a dip-moveout approach; Application to the mid-ocean ridge environment, Geophysics, 61, 821-834, 1996.

Mutter, J. C., S. M. Carbotte, W. Su, L. Xu, P. Buhl, R. S. Detrick, G. M. Kent, J. A. Orcutt and A. J. Harding, Seismic images of active magma systems beneath the East Pacific Rise between 17° 05' and 17° 35' S, Science, 374, 391-395, 1995.

Kappus, M. E. , A. J. Harding., and J. A. Orcutt, A baseline for upper crustal velocity variations along the East Pacific Rise at 13°N, J. Geophys. Res., 100, 6143-6161, 1995.

Phipps Morgan, J., A. J. Harding, G. M. Kent, J. A. Orcutt, and Y. J. Chen, An observational and theoretical synthesis of magma chamber geometry and crustal genesis along a mid-ocean ridge spreading center, in Magmatic Systems, ed. M. P. Ryan, pp139-178, Academic Press, New York, 1994.

Kent, G. M., A. J. Harding, J. A. Orcutt, R. S. Detrick, J. C. Mutter, and P. Buhl, Uniform accretion of oceanic crust south of the Garrett transform at 14° 15’S on the East Pacific Rise, J. Geophys. Res., 99, 9097-9116, 1994.

Tolstoy. M., A. J. Harding, and J. A. Orcutt, Crustal thickness on the Mid-Atlantic Ridge: Bull’s eye gravity anomalies and focused accretion, Science., 262, 726-729, 1993.

Kent, G. M., A. J. Harding, and J. A. Orcutt, Distribution of magma beneath the East Pacific Rise near the 9 03° N Overlapping Spreading Center from forward modeling of Common Depth Point data, J. Geophys. Res., 98, 13,971-13,995, 1993.

Kent, G. M. , A. J. Harding,, & J. A. Orcutt, Distribution of magma beneath the East Pacific Rise between the Clipperton Transform and the 9° 17' N Deval from forward modeling of common depth point data, J. Geophys. Res., 98, 13,945-13,969, 1993.

Harding, A.J., G. M. Kent, & J. A. Orcutt, A multichannel seismic investigation of upper crustal structure at 9° N on the East Pacific Rise: Implications for crustal accretion. J. Geophys. Res., 98, 13,925-13,944, 1993.

Chereskin, T. K., and A. J. Harding, Modeling the performance of an acoustic Doppler current profiler, J. Atmos. and Oceanic Tech., 10, 41-63, 1993.

Detrick, R. S., A. J. Harding, G. M. Kent, J. A. Orcutt, J. C. Mutter, P. Buhl, Seismic Structure of the Southern East Pacific Rise, Science, 259, 499-503, 1993.

Chereskin, T. K., and A. J. Harding, A model approach to predicting errors in acoustic doppler current profiles., Proc. Oceans, ‘92, 602-606, 1992.

Harding, A.J., G. M. Kent, M.E. Kappus and J.A. Orcutt, The Upper crust at 9° N East Pacific Rise, RIDGE Events, 2, 8-10, 1991.

Vera, E.E., Mutter J. C., Buhl P., Orcutt J. A., Harding A. J., Kappus, M. E., Detrick R. S., & Brocher T. M., The structure of 0- to 0.2 m.y. old oceanic crust at 9°N on the East Pacific Rise from expanded spread profiles, J. Geophys. Res., 95, 15,529-15,556 1990.

Kappus, M. E., Harding A. J., & Orcutt J. A., A comparison of tau-p transform methods, Geophysics., 55, 1202-1215, 1990.

Kent, G. M., Harding A. J., & Orcutt J. A, Evidence for a smaller magma chamber beneath the East Pacific Rise at 9°30’N, Nature, 344, 650-653, 1990.

Harding, A. J., Orcutt J. A., Kappus. M.E., Vera E.E., Buhl P., Mutter J. C., Detrick R. S., & Brocher T. M., The structure of young oceanic crust at 13°N on the East Pacific Rise from Expanding Spread Profiles, J. Geophys. Res., 94, 12,163-12,196, 1989.

Chereskin, T. K., Levine M.D., Harding A.J., & Regier L. A., Observation of near-inertial waves in acoustic Doppler current profiler measurements made during MILDEX, J. Geophys. Res., 94, 8135-8145 1989.

Mutter, J. C., Barth G. A., Buhl P., Detrick R. S., Orcutt J. A., & Harding A. J., Magma distribution across ridge axis discontinuities on the East Pacific Rise (8°40' to 9°50' North) from multichannel seismic images, Nature, 336, 156-158, 1988.

Harding, A. J., Book review: Deconvolution by Anton Ziolkowski, Geophys. J. R. astr. Soc., 82, 141, 1985.

Kennett, B. L. N., & Harding A. J., Is ray theory adequate for reflection seismic modelling (A survey of modelling methods) First Break, 3, 9-14, 1985.

Harding, A. J., Inversion methods for t - p maps of near offset data. Linear inversion. Geophysical Prospecting, 33, 674 - 695, 1985.

Harding, A. J., Slowness-time mapping of near offset seismic reflection data, Geophys. J. R. astr. Soc., 80, 463 - 492, 1985.

Kennett, B. L. N., & Harding A. J., Guided low frequency noise from airgun sources, Geophysical Prospecting, 32, 690-705, 1984.

Stephen, R. A., & Harding A. J., Travel time analysis of borehole seismic data. Journal. Geophys. Res., 88, 8289-8298, 1983.