Abstract

An inverse modelling study on the interpretation of magnetic anomalies caused by 2D dyke-shaped bodies was carried out using the differential search algorithm (DSA), a novel metaheuristic inspired by the migration of super-organisms. We aimed at estimating dyke parameters that include amplitude coefficient, depth, half-width, origin and dip angle. First, the resolvability of these parameters and algorithm-dependent parameters of the DSA that affect the performance were determined. Two theoretical and two field anomalies were used in the evaluations. Theoretical anomalies comprise one and two isolated dykes. The effect of noise content was also investigated in these cases. The inversion approach was then applied to two known magnetic field anomalies measured over the Marcona iron mine in Peru and the Pima copper mine in the US state of Arizona. The results showed that the efficiency of the DSA increases significantly with the use of optimal parameter sets of the inverse magnetic problem. Furthermore, cost function maps and relative frequency histograms showed that the parameters half-width and amplitude can be estimated with some uncertainties, while the remaining significant model parameters of the source body can be solved with negligible uncertainties. Findings indicated that the DSA provided satisfactory solutions in accordance with actual data and previously obtained results. Thus, it can be concluded that DSA is an efficient tool for interpreting magnetic anomalies caused by magnetised 2D dykes.

Research highlights

• Inverse modelling using Differential Search Algorithm for magnetic anomaly inversion is presented.

• The algorithm takes advantage of global optimization to interpret dyke-shaped bodies.

• Tests were carried out on two theoretical and field anomalies caused by dykes.

• Error energy maps and frequency distribution histograms show the ambiguities of the model parameters.

• It is a powerful tool to estimate the model parameters of thick dykes with proper control parameters.

中文翻译：

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通过差分搜索算法逆向建模解释二维堤状体引起的磁异常

摘要

使用差分搜索算法 (DSA) 对二维堤状体引起的磁异常解释进行了逆向建模研究，DSA 是一种受超级生物迁移启发的新型元启发式算法。我们旨在估计堤坝参数，包括振幅系数、深度、半宽、原点和倾角。首先，确定了这些参数的可解析性以及影响性能的 DSA 的算法相关参数。评估中使用了两个理论异常和两个场异常。理论异常包括一个和两个孤立的堤坝。在这些情况下还研究了噪声含量的影响。然后将反演方法应用于在秘鲁马科纳铁矿和美国亚利桑那州皮马铜矿测量的两个已知磁场异常。结果表明，随着使用逆磁问题的最佳参数集，DSA 的效率显着提高。此外，代价函数图和相对频率直方图表明，半宽和幅度参数可以在一些不确定性下估计，而源体的其余重要模型参数可以在不确定性可以忽略不计的情况下求解。结果表明，DSA 根据实际数据和先前获得的结果提供了令人满意的解决方案。因此，可以得出结论，DSA 是解释由磁化二维岩脉引起的磁异常的有效工具。代价函数图和相对频率直方图表明，半宽和幅值参数的估计具有一定的不确定性，而源体的其余重要模型参数可以在不确定性可以忽略不计的情况下求解。结果表明，DSA 根据实际数据和先前获得的结果提供了令人满意的解决方案。因此，可以得出结论，DSA 是解释由磁化二维岩脉引起的磁异常的有效工具。代价函数图和相对频率直方图表明，半宽和幅值参数的估计具有一定的不确定性，而源体的其余重要模型参数可以在不确定性可以忽略不计的情况下求解。结果表明，DSA 根据实际数据和先前获得的结果提供了令人满意的解决方案。因此，可以得出结论，DSA 是解释由磁化二维岩脉引起的磁异常的有效工具。结果表明，DSA 根据实际数据和先前获得的结果提供了令人满意的解决方案。因此，可以得出结论，DSA 是解释由磁化二维岩脉引起的磁异常的有效工具。结果表明，DSA 根据实际数据和先前获得的结果提供了令人满意的解决方案。因此，可以得出结论，DSA 是解释由磁化二维岩脉引起的磁异常的有效工具。

研究亮点

• 提出了使用差分搜索算法进行磁异常反演的反演建模。

• 该算法利用全局优化来解释堤状体。

• 对由堤坝引起的两个理论异常和现场异常进行了测试。

• 误差能量图和频率分布直方图显示了模型参数的模糊性。

• 它是用适当的控制参数估计厚堤模型参数的有力工具。