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.--

地震后经常发生的快速抗震变形为了解地壳的力学行为提供了天然的机会。在过去几年中，记录震后变形的大地测量数据集变得更加丰富和详细，但对这些数据集的许多研究仅限于记录特定机制与观测数据“一致”。各种各样的候选机制被提出作为负责任的过程，证明了震后变形在地球动力学中的重要性，但也证明了我们目前对这种现象缺乏了解。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和大地测量。这种方法将确定与数据一致的过程范围并排除其他过程，从而直接从大地测量数据限制地壳的流变性。将开发与发震断层相结合的剪切带形成和演化模型，以解决震后变形的来源是分布的还是局部的。这项研究将有助于了解地壳动力学过程的基本知识，并有助于我们评估其动力学过程的能力。对地震灾害的贡献。对剪切带形成的进一步了解将对结构地质学和机械工程产生影响，在这些领域，定位是一个永久的问题。这项工作的数据同化方面将有助于引入一种广泛成功的科学方法来解决断层力学问题。该项目代表了研究人员互补研究领域的融合，其中一个领域是地球动力学，另一个领域是大地测量学和数据同化。