Dr. Han performs 2D and 3D numerical simulations of convection to test the role of shear heating and fracture zones on Europan ridge formation. Her simulations show that a pre-existing fracture zone promotes upwelling, leading to topographic uplift of ~50 m. Shear heating also promotes upwelling, producing uplift of 100-120 m. Topography remains linear along fault strike even under the influence of heterogeneous 3D convection within the ice shell. Although central trough is not reproduced in the simulations, her studies support the idea that shear heating can produce ridge-like features on Europa.
Dr. Han and her collaborators start to perform numerical simulations to study the ridge formation on icy satellites to include the effects of non-Newtonian viscosity, elasticity, and plasticity and tidal dissipation in a more realistic way. These simulations will help us to explain and understand how ridges are formed and match the observed ridge topography, especially central trough.
Dr. Han and her collaborators perform numerical simulations of thermal convection in Europa's silicate mantle using the 3-D spherical finite element code, including tidal and radiogenic heating. These simulations will help the field to understand upper-mantle temperature structure, heat flux, and the extent to which partial melting (hence seafloor volcanism) occurs under conditions relevant to Europa.
Han, L., and A.P. Showman 2008. Implications of shear heating and fracture zones for ridge formation on Europa. GRL, Vol. 35, L03202, doi:10.1029/2007GL031957.
Han, L., and A. P. Showman 2007. Implications of shear heating and fracture zones for ridge formation on Europa. 38th Lunar and Planetary Science Conference.
Han, L., and A. P. Showman 2007. Implications of shear heating and fracture zones for ridge formation on Europa. 39th DPS Conference.