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ISSN 2096-7780 CN 10-1665/P

秦岭造山带及邻区双差层析成像

Double-difference tomography in the Qinling Orogenic Belt and its adjacent areas

  • 摘要: 秦岭造山带及邻区是华北克拉通、扬子克拉通与青藏高原东北缘的交汇地带,构造活动复杂。本文利用中国地震局在陕西、四川、甘肃等地的159个固定台站和中国地震科学台阵探测2期的182个宽频带流动台站的观测资料,在秦岭造山带及邻区采用双差层析成像方法获取其三维速度结构。结果表明:汉中盆地莫霍面深度为38 km,其形态呈现出中间凸两边凹的上拱形态;西秦岭造山带北缘和陇县—宝鸡断裂带南侧区域存在明显的低速异常呈西厚东薄的趋势,且一直延伸至39 km深度左右,与青藏高原中下地壳物质东流有关。

     

    Abstract: The Qinling Orogenic Belt and its adjacent areas serve as the convergence zone between the North China Craton, the Yangtze Craton, and the northeastern edge of the Tibetan Plateau and are characterized by complex tectonic activity. This study utilizes observational data from 159 fixed stations of the China Earthquake Administration in Shaanxi, Sichuan, Gansu, and other regions, as well as 182 broadband mobile stations from the second phase of the China Earthquake Scientific Array Detection project. We obtained a three-dimensional velocity structure of the Qinling Orogenic Belt and its adjacent areas by employing the double-difference tomography method. The imaging results reveal that the crustal thickness of the Hanzhong Basin is approximately 38 km, and the Moho interface exhibits a dome-like shape, convex in the center and concave on both sides. Additionally, a significant low-velocity anomaly is observed along the northern edge of the Western Qinling Orogenic Belt and the southern side of the Longxian-Baoji fault zone, extending to a depth of approximately 39 km. This anomaly is associated with the eastward flow of materials from the middle and lower crust of the Tibetan Plateau.

     

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