柴达木盆地北缘地壳运动与变形模式的精细研究

The Qaidam Basin is a large rift basin in the northeastern margin of the Tibet Plateau. The crustal movement and deformation pattern in the northern margin of the Qaidam Basin are of great scientific significance for revealing the basin-mountain coupling and the deformation and uplift of the Tibet Plateau. However, due to the limitations of the sparse regional observation and the unclear geometries of regional fault and block, the research conclusions of the crustal movement and deformation pattern in the northern margin of the Qaidam Basin are not yet consistent. This project aims to carry out the detailed research on crustal movement and deformation pattern in the northern margin of the Qaidam Basin. Research is mainly focused on three parts. The first is the extraction and accuracy evaluation of InSAR deformation field in the northern margin of the Qaidam Basin with high spatial resolution and precision by combining robust estimation, variance component estimation, Kalman filtering and InSAR techniques. The second is the refinement of the 3D fault geometry in the northern margin of the Qaidam Basin based on the dislocation model and the boundary element technique. The final is the determination of the detailed block movement and deformation pattern in the northern margin of the Qaidam Basin by considering the model resolution. The research results can improve the accuracy of InSAR data processing, overcome the difficulty of accuracy evaluation, explore the new way of refining fault geometry, and deepen the understanding of the basin-mountain coupling and the deformation and uplift of the Tibet Plateau.

柴达木盆地是青藏高原东北缘大型断陷盆地，其北缘地壳运动及变形模式对于揭示盆山耦合、青藏高原变形隆升过程具有重要科学意义。然而，由于区域观测稀疏、断层及块体几何形态不清晰等局限性，使得柴达木盆地北缘地壳运动与变形模式的研究结论尚不一致。本项目旨在开展柴达木盆地北缘地壳运动与变形模式的精细研究。重点研究（1）融合稳健估计、方差分量估计、卡尔曼滤波及InSAR技术提取柴达木盆地北缘的高空间分辨率、高精度InSAR形变场并进行精度评定；（2）采用位错模型和边界元技术精化柴达木盆地北缘的三维断层几何；（3）顾及模型分辨率反演柴达木盆地北缘的精细块体运动与变形模式。研究成果能够提升InSAR数据处理精度并克服精度评定难题，开拓断层几何精化研究的新途径，深化对盆山耦合、青藏高原变形隆升过程的认识。

柴达木盆地是青藏高原东北缘大型断陷盆地，其北缘地壳运动及变形模式对于揭示盆山耦合、青藏高原变形隆升过程具有重要科学意义。相关科学问题为理解该区域的活动构造、块体运动、变形机理等带来了机遇和挑战。项目围绕柴达木盆地北缘地壳运动与变形模式开展精细研究，设计并实现了融合稳健估计、方差分量估计、卡尔曼滤波、附加系统参数平差及InSAR技术的数据处理方法，实现了形变场精度的客观评定，获得了柴达木盆地北缘及周缘区域的高空间分辨率、高精度InSAR形变场，给出了精细运动和变形特征，评估了InSAR时序数据处理中的对流层延迟改正方法及其适用性。系统开展了采用位错模型和边界元技术的断层数值模拟，定量探究了局部背景应变场、同震滑移模式、断层几何、地质地貌、区域断裂滑动属性变化之间的联系，精化了区域三维断层几何及滑移模式，基于位错模型和最佳库仑应力数学模型研制了库仑应力变化软件。基于三维弹性块体模型定量探究了断层闭锁分辨率、断层识别及数据融合对模型分辨率的影响，建立了断层、块体的精细几何模型，顾及模型分辨率反演确定了断层滑移速率、闭锁程度及滑移亏损分布，构建了柴达木盆地北缘的精细块体运动及变形模式，并结合历史地震数据进行了区域地震危险性分析。在项目执行期间和支持下，项目组发表了19篇论文，其中8篇SCI论文，8篇EI论文；培养了4名博士、6名硕士；获得了1项软件著作权、1项发明专利。项目组实现了研究目标。项目研究结果有助于揭示柴达木盆地北缘地壳运动与变形模式，能够发展InSAR数据处理方法、提升数据处理精度并克服精度评定难题，能够促进边界元技术在断层几何精化中的应用，能够深化对盆山耦合、青藏高原变形隆升过程的认识。