任意形状三度体磁场可视化人机交互反演

Magnetic Interactive Visualized Inversion on Arbitrary Shaped Three-Dimensional Body

采用任意形状三度体人机交互反演方法解释复杂形态磁性体。其作法是采用直立线元法近似计算地质体产生的磁异常,利用可视化技术实现人机交互反演。通过理论模型分析了影响精度的因素:当剖分剖面数由17减为3时,近似计算的均方误差由0.099nT增大到3.160nT,说明剖分剖面数越多,近似计算的误差越小;当剖分剖面数固定时,地质体中心深度由100m增加到500m,近似计算的最大相对误差从39.19%下降到7.84%,说明中心深度越大,近似计算的误差越小。因此,合理确定剖分剖面数是提高精度的关键。提出了提高近似计算精度的2种措施:模型剖分准则和位场曲线约束模型准则。将该方法应用于澳大利亚艾尔半岛某矿区条带状含铁建造(BIF)的评价,控制钻孔证实了反演解释的结果。

Interactive inversion of arbitrary shaped three-dimensional body is used to explain complex magnetic body.This approach can be described as follow： the vertical line element method is used to calculate the geological magnetic anomalies,and the visualized technology was used to achieve human-computer interactive inversion.The accuracy affect factors were analyzed through theoretical model： when the number of split sections decrease from 17 to 3,the approximate calculation of the mean square error increased from 0.099 nT to 3.160 nT.The approximate calculation errors will be much smaller when the divided sections number is more.When the divided sections number is fixed,as the center depth increases from 100 meters to 500 meters,the maximum relative error decreased from 39.19% to 7.84%.This indicated that the deeper the center depth,the smaller approximate calculation error gets.Therefore how to divide magnetic body reasonably is the main aspect to improve inversion precision.And two improvement measures are proposed： the model division criterion and potential curve restriction criterion were employed and that can be improved the calculation accuracy.This method is applied in estimating banded iron formation（BIF） of a deposit in Eyre Peninsula,South Australia.The inversion interpreting result is validated by boreholes