• ISSN 2097-1893
    • CN 10-1855/P

    塔里木盆地与天山地区地震各向异性研究进展

    Research progress on seismic anisotropy in the Tarim Basin and Tianshan region

    • 摘要: 塔里木盆地与天山地区是中亚造山带与稳定地块的关键交互带,是研究大陆内部构造变形、盆山耦合作用及地震孕育机制的天然实验室. 地震各向异性作为岩石圈变形的“指示剂”,能够有效反映区域构造应力场和深部物质运移特征,对揭示该区域盆山耦合动力学机制具有重要科学意义. 近些年来,国内外学者利用接收函数、剪切波分裂和面波层析成像等地震学方法,系统研究了从地壳到上地幔的地震各向异性特征. 研究表明,地壳地震各向异性具有显著空间分异,总体上塔里木盆地与天山地区快波偏振方向与区域构造应力场以及天山造山带走向一致,主要是受印度板块碰撞的远程效应、青藏高原隆升以及与天山山脉NS向推挤作用的影响. 但局部区域快波偏振方向分散,阿图什、乌什以及柯坪等区域各向异性特征呈现出一定的复杂性,可能与局部断裂的应力扰动有关. 上地幔各向异性特征与地壳各向异性特征并不完全一致,岩石圈变形的垂直连贯性有待进一步探讨. 尽管国内外学者在地震各向异性领域取得上述进展,但地震各向异性的空间分布特征与动力学机制探讨尚未达成统一,未来研究仍需要进行大量的地球物理观测,深化地震各向异性与构造变形、地震活动的关系,为区域地震危险性评估提供更可靠的深部动力学约束.

       

      Abstract: The Tarim Basin and the Tianshan region are the key interaction zones between the Central Asian Orogenic Belt and stable blocks, and are natural laboratories for studying the tectonic deformation of the continent, the coupling effect of basin-mountain and the seismic breeding mechanism of the continent. As an “indicator” of lithospheric deformation, seismic anisotropy can effectively reflect the regional tectonic stress field and deep material migration characteristics, which is of great scientific significance for revealing the coupling dynamics mechanism of basin-mountain in this region. In recent years, domestic and international scholars have systematically studied the seismic anisotropy characteristics from the crust to the upper mantle using seismological methods such as receiver functions, shear wave splitting, and surface wave tomography. Research shows that there are significant spatial differences in crustal seismic anisotropy. Generally, the fast wave polarization directions in the Tarim Basin and the Tianshan region are consistent with the regional tectonic stress field and the strike of the Tianshan orogenic belt, which is mainly affected by the long-range effect of the Indian plate collision, the uplift of the Qinghai-Tibet Plateau, and the NS pushing action with the Tianshan Mountains. However, the fast wave polarization directions are dispersed in local areas, and the anisotropic characteristics in regions such as Atushi, Wushi and Keping exhibit a certain degree of complexity, which may be related to stress disturbances caused by local faults. The anisotropic features of the upper mantle are not entirely consistent with those of the crust, and the vertical coherence of lithospheric deformation requires further investigation. Although scholars at home and abroad have made the above progress in the field of seismic anisotropy, the spatial distribution characteristics and dynamic mechanism of seismic anisotropy have not yet reached a unified discussion, and a large number of geophysical observations are still needed to deepen the relationship between seismic anisotropy and tectonic deformation and seismic activity, so as to provide more reliable deep dynamic constraints for regional seismic risk assessment.

       

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