王逸宸, 柳林涛, 许厚泽. 多尺度源网重力与重力梯度联合聚焦反演[J]. 武汉大学学报 ( 信息科学版), 2022, 47(2): 181-188. DOI: 10.13203/j.whugis20190263
引用本文: 王逸宸, 柳林涛, 许厚泽. 多尺度源网重力与重力梯度联合聚焦反演[J]. 武汉大学学报 ( 信息科学版), 2022, 47(2): 181-188. DOI: 10.13203/j.whugis20190263
WANG Yichen, LIU Lintao, XU Houze. Integrated Focusing Inversion of Gravity and Gravity Gradients with Multi-scale Source Grids[J]. Geomatics and Information Science of Wuhan University, 2022, 47(2): 181-188. DOI: 10.13203/j.whugis20190263
Citation: WANG Yichen, LIU Lintao, XU Houze. Integrated Focusing Inversion of Gravity and Gravity Gradients with Multi-scale Source Grids[J]. Geomatics and Information Science of Wuhan University, 2022, 47(2): 181-188. DOI: 10.13203/j.whugis20190263

多尺度源网重力与重力梯度联合聚焦反演

Integrated Focusing Inversion of Gravity and Gravity Gradients with Multi-scale Source Grids

  • 摘要: 在重力聚焦反演基础上提出多尺度源网聚焦反演算法。首先,对源网进行粗网格剖分,用共轭梯度法求解粗网格源网模型的聚焦解,直到拟合差下降至设定的数值;然后,将粗网格得到的密度映射到细网格;最后,以细网格模型为初始模型,进一步迭代直到拟合差下降至符合反演要求。模型试验结果显示,相比于固定源网反演,多尺度源网聚焦反演迭代的总耗时缩短50%以上。所提算法对单体模型、同参数双体模型和不同参数双体模型均比固定源网聚焦反演有更好分辨能力,对底边更深或整体埋深更大的模型分辨能力明显提高。实测数据试验结果显示,采用澳大利亚Kauring地区的实测重力和重力梯度数据反演计算,反演结果与前人一致,说明所提算法适用于实测数据。

     

    Abstract:
      Objectives  Based on the gravity focusing inversion, we propose the multi-scale source grid focusing inversion. This method aims to reduce the computation time and improve the spatial resolution of the focusing inversion.
      Methods  Firstly, the source grid is divided into the coarse grid, which contains less cells than the regular grid. Then we perform the focusing inversion in the coarse grid using conjugate gradient method. In the coarse grid phase it consumes short computation time for each iteration. Secondly, as the relative residual decreases to a low threshold value, the iteration is suspended and the coarse grid density is mapped into the fine grid. We compared 3 density mapping methods. Those methods use the average value of coarse cells, the value of the maximum area coarse cell and the maximum value of coarse cells. Then we adopt the average value method for the optimum density mapping. Finally, the iteration is resumed in the fine grid and converges to the final solution.
      Results  The model testing result shows: (1) More than 50% computation time is cut down by using the multi-scale source grid. (2)Compare to the single scale focusing inversion, the multi-scale source grid focusing inversion of gravity and gravity gradient data considerably improve the revelation of the single hexahedron model, the double hexahedrons model placed horizontally and the double hexahedrons model with different sizes and depths. (3)In particular the revelation of the body bottom or the deeper bodies is improved from the regular gravity inversions. The measured data testing result shows: (1)The inversion result of gravity and gravity gradient data of Kauring testing ground is generally consistent with the known results. The revelation of the top and bottom of the center anomaly body is close to the previous results. (2)The result indicates the larger depth of the south side anomaly body than the previous results. That supports the wide and gentle slope form of the gravity gz data at the south side.
      Conclusions  The multi-scale grid focusing inversion can process the gravity or/and gravity gradient simulated or measured data. This method significantly reduces the computation time and improves the resolution ability from the regular focusing inversion with the single scale source grid.

     

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