方炜, 白超英, 彭建兵. 2013: 黄土高原及邻区地壳P波速度结构. 地震学报, 35(3): 315-327. DOI: 10.3969/j.issn.0253-3782.2013.03.004
引用本文: 方炜, 白超英, 彭建兵. 2013: 黄土高原及邻区地壳P波速度结构. 地震学报, 35(3): 315-327. DOI: 10.3969/j.issn.0253-3782.2013.03.004
Fang Wei, Bai Chaoying, Peng Jianbing. 2013: Crustal P-wave velocity beneath the Loess Plateau and its surrounding region. Acta Seismologica Sinica, 35(3): 315-327. DOI: 10.3969/j.issn.0253-3782.2013.03.004
Citation: Fang Wei, Bai Chaoying, Peng Jianbing. 2013: Crustal P-wave velocity beneath the Loess Plateau and its surrounding region. Acta Seismologica Sinica, 35(3): 315-327. DOI: 10.3969/j.issn.0253-3782.2013.03.004

黄土高原及邻区地壳P波速度结构

Crustal P-wave velocity beneath the Loess Plateau and its surrounding region

  • 摘要: 利用地震波走时联合反演算法(改进型最短路径算法)进行三维弯曲地震射线追踪正演, 以及共轭梯度法求解带约束的阻尼最小二乘问题进行反演, 同时更新速度模型和地震震中位置, 结合地方震和区域地震走时资料得到了黄土高原(含汾渭断陷盆地)及邻区地壳三维P波速度结构. 其横向变化结果表明, 研究区地壳内的P波高速异常区与其内的地震活动构造带相一致, 地震多发生在P波高速异常区的边缘或高、 低速异常区的交汇处. 秦岭山区和鄂尔多斯块体东南区为P波低速异常区. 而垂向变化结果则表明研究区存在低速异常区.

     

    Abstract: A simultaneous travel time inversion procedure was developed in collaboration with a modified shortest path algorithm, which was applied to a bent ray tracing forward calculation. The conjugate gradient algorithm was used to solve a damped least square problem. The crustal P-wave velocity structure beneath the Loess Plateau and its surrounding regions of China were tomographically imagined down to the depth of 50 km by inverting P wave travel time data from local and regional earthquakes. The result indicates that lateral high velocity anomaly regions generally coincide with the seismically active zones, while vertical velocity variations show existence of a low velocity zone.

     

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