Lars Hansen

Lars Hansen

Visiting Fellow

My research focuses on the rheological properties of rocks at high temperatures and pressures, and I run the Rock Rheology Laboratory. I primarily use laboratory-based experiments to investigate the mechanisms of viscous deformation at the atomic scale and the manner in which those mechanisms control the dynamics of the solid Earth at the scale of tectonic plates. I also use detailed field work to test predictions from laboratory-based models. Specific interests include the affect of microstructure (dislocation density, grain size, phase distribution, crystallographic texture) on rock viscosity, the evolution of crystallographic texture and seismic anisotropy, strain localization and formation of lithospheric shear zones, microanalysis of deformed materials (primarily through electron microscopy), and the development of new methods for the mechanical testing of rocks.

T. B. Britton, J. Jiang, Y. Guo, A. Vilalta-Clemente, D. Wallis, L. N. Hansen, A Winkelmann, A. J. Wilkinson (2016), Tutorial: Crystal orientations and EBSD – Or which way is up?, Materials Characterization, doi:10.1016/j.matchar.2016.04.008.

L. N. Hansen, J. M. Warren, M. E. Zimmerman, D. L. Kohlstedt (2016), Viscous anisotropy of textured olivine aggregates, Part 1: Measurement of the magnitude and evolution of anisotropy, Earth Planet. Sci. Lett., 445, 92–103, doi:10.1016/j.epsl.2016.04.008.

J. A. Tielke, L. N. Hansen, M. Tasaka, C. Meyers, M. E. Zimmerman, D. L. Kohlstedt (2016), Observations of grain-size sensitive power-law creep of olivine aggregates over a large range of lattice-preferred orientation strength, J. Geophys. Res.

P. Skemer and L.N. Hansen (2016), Inferring mantle flow from seismic anisotropy: An experimental perspective, Tectonophysics, 668–669, 1–14, doi:10.1016/j.tecto.2015.12.003.

D.L. Kohlstedt and L. N. Hansen (2015), Constitutive equations, rheological behavior, and viscosity of rocks, in: Gerald Schubert (editor-in-chief) Treatise on Geophysics, 2nd edition, 2, 441–472.

L. N. Hansen and J. M. Warren (2015), Quantifying the effect of pyroxene on deformation of peridotite in a natural shear zone, J. Geophys. Res., 120, doi:10.1002/2014JB011584.

L. N. Hansen, Y. -H. Zhao, M. E. Zimmerman, D. L. Kohlstedt (2014), Protracted fabric evolution in olivine: Implications for the relationship among strain, crystallographic fabric, and seismic anisotropy, Earth Planet. Sci. Lett., 387, 157-158.

L. N. Hansen, M. Cheadle, B. John, H. Dick, B. Tucholke, M. Tivey (2013), Mylonitic deformation at the Kane Oceanic Core Complex: Implications for the rheological characteristics of oceanic detachment faults, Geochem., Geophys., Geosys., (14) 8, 3085-3108.

P. Skemer, J. M. Warren, L. N. Hansen, G. Hirth, P. B. Kelemen (2013), The influence of water and LPO on the initiation and evolution of mantle shear zones, Earth Planet. Sci. Lett., 375, 222-233.

L. N. Hansen, M. E. Zimmerman, D. L. Kohlstedt (2012), Laboratory measurements of the anisotropic viscosity of olivine, Nature, 492, 415–418.

L. N. Hansen, M. E. Zimmerman, D. L. Kohlstedt (2012), The influence of microstructure on deformation of olivine in the grain-boundary sliding regime, J. Geophys. Res., 117, B09201.

L. N. Hansen, M. E. Zimmerman, A. Dillman, D. L. Kohlstedt (2012), Strain localization in olivine aggregates at high temperature: An experimental comparison of constant-strain-rate and constant-stress boundary conditions, Earth Planet. Sci. Lett., 333–334, 134–145.

L. N. Hansen, M. E. Zimmerman, D. L. Kohlstedt (2011), Grain-boundary sliding in San Carlos olivine: Flow law parameters and crystallographic-preferred orientation, J. Geophys. Res., 116, B08201.