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| A fast estimation method of magnetic-source parameters based on the vertical difference of normalized source strength |
HUANG Yuan-Sheng1,2( ), WANG Yan-Guo1(), LUO Xiao3 |
1. School of Geophysics and Measure-control Technology, East China University of Technology, Nanchang 330013, China
2. Hainan Investigation Institute of Hydrogeology and Engineering Geology, Haikou 571100, China
3. No. 230 Research Institute of Nuclear Industry, Changsha 410011, China |
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Abstract Fast automatic inversion is a primary tool for magnetic data interpretation. The normalized source strength (NSS) is one main method for three-dimensional magnetic data interpretation as it is independent of magnetization direction. In this paper, the vertical difference of the normalized source of strength is introduced, and a fast estimation method of magnetic-source parameters based on the vertical difference of normalized source strength is derived in the light of the vertical difference of NSS at different height. In addition, upward continuation of suitable height can be used to improve the stability of the method. Model tests shows that the vertical difference of NSS has higher resolution ability and can recognize the horizontal locations of magnetic sources, and the proposed automatic inversion method can obtain the depths and structural indices of the sources. In this paper, the proposed method is applied to magnetic anomaly of M area over Inner Mongolia, and obtain the horizontal locations, depths and structural indices of magnetic sources. The results could provide useful information for forecasting the distribution of concealed rock mass.
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Received: 09 February 2021
Published: 21 December 2021
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Corresponding Authors:
WANG Yan-Guo
E-mail: 1289418554@qq.com;wangyg8503@126.com
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Inversion results of magnetic anomaly produced by a single sphere model (z1=0 km, z2=0.2 km)
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模型体
编号 | 模型体
类型 | 边长或半径/
km | 上顶或质心
埋深/km | 下底/
km | 磁化方向
(倾角,偏角) | 磁化强度/
(A·m-1) | | ① | 球体(N=3) | 0.5 | 1.5 | | (45°, 45°) | 1 | | ② | 棱柱体(N≈0) | 5×5 | 0.5 | 10 | (60°, 45°) | 0.1 | | ③ | 薄板(N≈1) | 4×4 | 0.5 | 0.6 | (0°, 45°) | 1 | | ④ | 岩脉(N=1) | 16×0.2 | 1 | 100 | (30°, 45°) | 1 |
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The parameters of the multisource model
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Forward magnetic anomaly of multi-source model
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Inversion results of the noise-free synthetic magnetic anomaly (z1=0 km,z2=-0.2 km)
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Synthetic magnetic anomaly added by 1% random noise
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Inversion results of noisy magnetic anomaly (z1=0 km, z2=-0.2 km)
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Inversion results of noisy magnetic anomaly (z1=-0.3 km, z2=-0.5 km)
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Inversion results of noisy magnetic anomaly (z1=-0.5 km, z2=-0.7 km)
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| 反演结果 | 球体 | | | 棱柱体 | | | 薄板 | | | 岩脉 | | | | z0(1.5) | N(3) | | z0(0.5) | N(0) | z0(0.5) | N(1) | z0(1.0) | N(1) | | 无噪声 | z1=0, z2=-0.2 | 1.52 | 3.00 | | 0.61 | 0.34 | | 0.51 | 0.77 | | 1.08 | 1.16 | | | | 含噪声 | z1=-0.3, z2=-0.5 | 1.46 | 2.88 | | 0.74 | 0.63 | | 0.51 | 0.76 | | 1.09 | 1.18 | | | | z1=-0.5, z2=-0.7 | 1.54 | 3.05 | | 0.94 | 0.80 | | 0.45 | 0.61 | | 1.09 | 1.18 | | |
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Inversion results of noise-free and noise-added synthetic magnetic anomaly at different altitudes
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Geological map of M area of Inner Mongolia
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Inversion results of magnetic data over M area (z1=-0.5 km,z2=-0.75 km)
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