天山构造带地震各向异性及动力学机制研究进展

天山构造带及邻区的深部动力学机制是地球动力学研究的热点，而地震各向异性是区域构造深部动力学机制的一个重要性质。研究表明，天山构造带上地壳各向异性结果呈现区域性分区，受到构造带与断裂走向和区域应力影响；上地幔各向异性的结果认为快波偏振方向和构造带走向基本平行，但在伊塞克湖附近、塔里木盆地和准噶尔盆地挤压区域各向异性快波方向变化复杂，垂直方向上的变化可能由区域性双层各向异性引起，但局部复杂性原因有待进一步探讨。诸多研究支持天山构造带的地壳与上地幔垂直连贯变形机制。此外，地幔柱、软流圈变形、小尺度地幔对流等概念均被用来解释天山构造带的动力学背景，表明该地区的深部动力学机制非常复杂，需要更深入的探讨。

Research Progress of Seismic Anisotropy and Dynamic Mechanism in the Tienshan Region

Deep dynamic mechanism of the Tienshan region is a hot spot in geodynamics research,and seismic anisotropy is an important feature of the deep dynamic mechanism of the regional structure. The results show that the crust anisotropy of the Tienshan region is regional and affected by tectonic belt,fault strikes and regional stress. The upper mantle anisotropy shows that the fast polarization direction is generally parallel to the strike of the Tienshan tectonic belt,but becomes complex near the Issyk-Kul Lake,Tarim Basin and Junggar Basin,and regional double-layer anisotropy phenomenon exist in local area. The complex vertical variation may be due to the regional double layer anisotropy,but also needs further study to prove. Many researches about the crust and mantle of the Tienshan region support vertical coherent deformation mechanism. In addition,the mantle plume,asthenosphere deformation and small-scale mantle convection are all used to explain the dynamic mechanisms in the Tienshan area,which indicate the deep dynamic mechanism needs further research.