Christopher Thom

Christopher Thom

Postdoctoral Research Assistant

I am an experimental geophysicist interested in a number of problems at the intersection of geology, materials science, and engineering. I utilize both traditional (e.g. uniaxial and multi-anvil geometry) and non-traditional (e.g. nanoindentation and atomic force microscopy) rock deformation techniques to measure the friction and rheology of a wide range of geologic materials.  I have experience measuring both brittle and ductile deformation mechanisms and take a unique approach to provide laboratory constraints on large scale geodynamic problems. My current research is focused on quantifying the role of internal stress in the anelasticity of geologic materials and examining the nano- to micro-mechanics that occurs at olivine grain boundaries undergoing deformation.  Other current and future interests include the mechanics of earthquake nucleation from a contact mechanics and physics-based approach, the scale-dependent deformation mechanisms that produce geometric complexity in fault systems, the attenuation of geologic materials over a wide range of relevant frequencies, and weakening of materials during phase transformations.

1.  Thom, C.A., Brodsky, E.E., Carpick, R.W., Pharr, G.M., Oliver, W.C., and Goldsby, D.L. (2017), Nanoscale roughness of natural fault surfaces controlled by scale-dependent yield strength. Geophysical Research Letters, 44 (18), 9299-9307. doi:10.1002/2017GL074663


2.  Kumamoto, K. M., Thom, C.A., Wallis, D., Hansen, L.N., Armstrong, D.E.J., Warren, J.M., Goldsby, D.L., and Wilkinson, A.J. (2017), Size effects resolve discrepancies in 40 years of work on low-temperature plasticity in olivine. Science Advances, 3, e1701338. doi:10.1126/sciadv.1701338


3.  Thom, C.A., Carpick, R.W., and Goldsby, D.L. (2018), Constraints on the physical mechanism of frictional aging from nanoindentation. Geophysical Research Letters, 45 (24), 13,306-13,311. doi:10.1029/2018GL080561


4.  Thom, C.A. and Goldsby, D.L. (2019), Nanoindentation studies of plasticity and dislocation creep in halite. Geosciences, 9 (2), 79, doi: 10.3390/geosciences9020079


5.  Hansen, L.N., Kumamoto, K.M., Thom, C.A., Wallis, D., Durham, W.B., Goldsby, D.L., Breithaupt, T., Meyers, C.D., and Kohlstedt, D.L. (2019), Low-temperature plasticity in olivine: Grain size, strain hardening, and the strength of the lithosphere. Journal of Geophysical Research: Solid Earth, 124 (6), 5427-5449, doi: 10.1029/2018JB016736


6.  Okamoto, K., Brodsky, E.E., Thom, C.A., Smeraglia, L., and Billi, A. (in review at Geophysical Research Letters), The minimum scale of grooving on a recently ruptured limestone fault.


7.  Wallis, D., Hansen, L.N., Kumamoto, K.M., Thom, C.A., Plumper, O., Ohl, M., Durham, W.B., Goldsby, D.L., Armstrong, D.E.J., Meyers, C.D., Goddard, R., Warren, J.M., Breithaupt, T., Drury, M.R., and Wilkinson, A.J. (submitted to EPSL), Dislocation interactions during low-temperature plasticity of olivine strengthen the lithospheric mantle.


8.  Thom, C.A., Liang, Z., Pharr, G.M., and Goldsby, D.L. (in prep. for EPSL), Diffusion creep and grain boundary sliding in ice by nanoindentation.


9.  Seiphoori, A., Thom, C.A., Goldsby, D.L., and Marschall, P. (in prep.), Diagenetic cementation effects on the pore structure and micromechanical properties of Opalinus Clay-shale.