HR: 1400h
AN: P33A-02    [Abstracts]
TI: Tidally Driven Strike-Slip Fault Activity at Enceladus's Tiger Stripes
AU: Smith-Konter, B R
EM: brkonter@utep.edu
AF: University of Texas at El Paso, Department of Geological Sciences, El Paso, TX 79968, United States
AU: Olgin, J
EM: jolgin@miners.utep.edu
AF: University of Texas at El Paso, Department of Geological Sciences, El Paso, TX 79968, United States
AU: * Pappalardo, R T
EM: robert.pappalardo@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology M/S 183-301, Pasadena, CA 91109, United States
AB: Straddling the south polar region of Enceladus, the four principal tiger stripe fractures are a likely source of tectonic activity and plume generation. Here we investigate tidally driven stress conditions at the tiger stripe fractures through a combined analysis of shear and normal diurnal tidal stresses. We compute Coulomb failure conditions to assess likely failure location, timing, and direction (right- vs. left-lateral slip) throughout the Enceladus orbital cycle and explore a suite of model parameters that inhibit or promote shear failure at the tiger stripes. We find that low coefficients of friction (μ_f = 0.1-0.2) and shallow fracture depths (2-4 km) permit shear failure along the tiger stripe faults, and that right- and/or left-lateral slip responses are possible. We integrate these conditions into a 3D time-dependent fault dislocation model to evaluate tectonic displacements and stress variations at depth during a tiger stripe orbital cycle. In this model, the sequence of stress accumulation and subsequent fault slip varies as a function of fault location and orientation, frictional coefficient, and fault depth. We estimate shear stress accumulation of ∼70 kPa prior to fault failure, which can generate strike-slip displacements on the order of ∼0.5 m in the horizontal direction and ∼5 mm in the vertical direction per slip event. Tectonic activity inferred from these analyses positively correlates with observed plume activity and temperature anomalies at the tiger stripes, however in detail some regions of our model do not strongly match the observations. In these regions, future work will tune the model, varying frictional and fault geometry parameters, to best simulate the available plume and temperature anomaly data.
DE: 5422 Ices
DE: 5475 Tectonics (8149)
DE: 5770 Tidal forces
DE: 6280 Saturnian satellites
DE: 8168 Stresses: general
SC: Planetary Sciences [P]
MN: 2009 Joint Assembly