Thermal-Mechanical Behavior of Oceanic Transform Faults

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The researchers will conduct a study to investigate the thermo-mechanical behavior of oceanic transform faults to address the discrepancies between the geologic observations and the predictions from numerical models. Previous studies that incorporated 3-D conductive and advective heat transport surrounding transform faults used simplified rheologic and heat transport relationships to simulate the behavior of the lithosphere and underlying asthenosphere. For example, most of these studies ignored important effects, such as brittle weakening of the lithosphere, non-linear rheology, shear-heating, hydrothermal circulation, and serpentinization. Moreover, although the half-space cooling model does the best job explaining the depth of transform fault seismicity, it neglects all physics associated with mantle flow. The goal of the proposed study is to create more self-consistent models for the behavior of oceanic transform faults that incorporate: 1) Hydrothermal circulation and shear-heating (viscous dissipation) 2) Brittle deformation processes and metamorphism 3) Non-linear and grain-size dependent rheology Initial results simulating brittle weakening suggest that a more realistic treatment of rheology, based on laboratory data, may explain many of the seemingly discrepant observations at oceanic transform faults. Broader impacts include support for a young scientist and a graduate student.