Contributions of Ductile Shear Zones to Postseismic Deformation: Mechanical Advances and Data Assimilation

延性剪切带对震后变形的贡献：机械进步和数据同化

• 批准号: 0337678
• 负责人: Laurent Montesi
• 金额: $ 24.72万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0337678&HistoricalAwards=false
• 关键词: Contributions; Ductile; Shear; Zones; Postseismic

The rapid aseismic deformation that often follows earthquakes provides a natural opportunity to learn about the mechanical behavior of the Earth's crust. Geodetic data sets documenting postseismic deformation have become much more plentiful and detailed in the last few years, yet many studies of these data sets have been limited to documenting that a particular mechanism "is consistent with" the observed data. The wide variety of candidate mechanisms that have been proposed as the responsible process testifies to the importance of postseismic deformation in geodynamics, but also to our current lack of understanding of this phenomenon. The proposed study will combine a modeling framework that can simultaneously consider multiple rheological behaviors with the geodetic observations through a data assimilation algorithm. This approach, will identify the range of processes consistent with the data and rule out others, constraining the rheology of the crust directly from geodetic data. Models of shear zone formation and evolution coupled with a seismogenic fault will be developed to address whether the source of postseismic deformation is distributed or localized.The proposed study will contribute to basic knowledge of dynamical processes in the Earth's crust and to our ability to evaluate their contribution to earthquake hazards. The improved understanding of shear zone formation will have implications for structural geology and mechanical engineering, where localization is a permanent concern. The data assimilation aspect of this work will help introduce a widely successful scientific approach to fault mechanics problems. The project represents the merging of the complementary research fields of the investigators, geodynamics for one, and geodesy and data assimilation for the other.--

经常遵循地震的快速无性变形为学习地球外壳的机械行为提供了自然的机会。在过去的几年中，记录了地震变形的大地数据集已变得更加丰富和详细，但是对这些数据集的许多研究都仅限于记录特定机制“与观察到的数据一致”。提出的作为负责任过程的各种候选机制都证明了地球动力学后地震变形的重要性，也证明了我们目前对这种现象的不了解。拟议的研究将结合一个建模框架，该框架可以通过数据同化算法同时考虑多种流变行为与大地测量。这种方法将确定与数据一致的过程范围并排除其他过程，从而直接从地球数据中限制了地壳的流变。将开发剪切带形成和进化的模型，再加上地震断层，以解决地震后变形的来源是否分布或局部。拟议的研究将有助于地球壳中动态过程的基本知识，以及我们评估其对地震危害的贡献的能力。对剪切带形成的改进理解将对结构地质和机械工程产生影响，在该结构地质和机械工程中，本地化是一个永久关注的问题。这项工作的数据同化方面将有助于引入广泛成功的科学方法来解决故障力学问题。该项目代表了研究人员的补充研究领域的合并，一个地球动力学以及另一个的地理学和数据同化。