Rheology of Mantle Minerals In Subducted Slabs: Limits on Deep Seismicity

深源地震过程仍然知之甚少。 俯冲板块的材料强度可能会限制这些事件的分布和规模。 此外，塑性不稳定性仍然是这些事件的可能原因。 在这项研究中获得的数据将定义这些事件的断层材料的流变学施加的限制。 PI及其同事将研究橄榄石，wadsleyite和ringwoodite相在俯冲板的压力和温度域中的流变特性。将使用一个同步加速器X辐射源与一个多砧高压系统相结合，在高达20 GPa的压力范围和从室温到1200 ℃的温度下对这些材料进行实验研究。该方法是表征的流变学和基本的过程，管理在适当的压力和温度条件下的俯冲板流。 研究人员将确定材料强度的温度依赖性以及在这些条件下的应力-应变率关系。 这些信息将产生流动过程的活化能的估计。 通过透射电子显微镜，他们将表征对应于不同变形状态的材料的位错密度和结构。 总之，这些数据将有助于推断俯冲板片中存在的可能条件，并将有助于限制地震过程以及描绘

Weidner 9909266 The deep focus earthquake process remains poorly understood. The strength of the material of the subducting slab may limit the distribution and size of these events. Furthermore, plastic instabilities remain as a possible cause of these events. The data obtained in this study will define the limitations imposed by the rheology of the faulting material on these events. The PI and colleagues will investigate the rheological properties of the olivine, wadsleyite, and ringwoodite phases in the pressure and temperature domain of a subducting slab. A synchrotron x-radiation source coupled with a multi-anvil high-pressure system will be used to conduct an experimental study of these materials in the pressure range up to 20 GPa and temperatures from room temperature to 1200C. The approach is to characterize the rheology and underlying processes that govern flow in the appropriate pressure and temperature conditions of a subducting slab. The investigators will determine the temperature dependence of the strength of the materials and the stress - strain rate relation at these conditions. This information will yield estimates of activation energies for the flow process. With transmission electron microscopy, they will characterize the dislocation density and structure of the material corresponding to different regimes of the deformation. Taken together, these data will be useful to extrapolate to possible conditions that exist in the subducting slab and will be useful for constraining the earthquake process as well as delineating