论文部分内容阅读
我们以广为应用的三度体为理论模型,讨论了三度磁性体磁异常的振幅谱和相位谱的平面特征。影响其平面波谱的主要因素有磁化倾角θ和磁化偏角D以及三度体的水平尺寸b和c。振幅谱:在相位因子φ_1=0的情况下,三度体的长轴与x方向一致,这时:1)当D=0或D=(π/2)时,θ角的变化不影响振幅谱的对称性,只影响振幅值,θ越小振幅值越小;2)当θ=(π/2)时,振幅值达到极大;3)当Dm0或Dm(π/2)时,θ的变化同时影响对称性和振幅值。θ越小对称性越差,振幅值也越小;4)当b=c时,D由0变到(π/2),振幅谱内等值线圈向一个方向伸长。当b＝c时,振幅谱内等值线圈的伸长方向与b=c时相同。在相位因子φ_1m0的情况下,三度体的长轴与x方向不一致,这时,只要作一坐标变换,在新的坐标系中,振幅谱的图形与φ_1=0时的图形相同。相位谱:在相位因子φ_1=0,位移因子x_0=y_0=0时,三度体中心位置位于坐标原点正下方,相位谱等值线为一系列交于原点的放射状直线;当x_0m0,y_0m0时,相位谱图形出现周期性变化,但只要作适当的换算,仍可得到与x_0=y_0=0时相同的图形。在φ_1m0的情况下,仍按振幅谱的作法,进行坐标变换,便可得到与φ_1=0时相同的图形。根据上述振幅谱和相位谱的特征,可以确定磁化倾角θ和磁化偏角D。
Based on the widely applied third-order model, we discuss the planar features of the amplitude and phase spectra of magnetic anomalies of the third-order magnetic body. The main factors affecting the plane spectrum are the magnetization tilt θ and the magnetization declination D, and the horizontal dimensions b and c of the third body. Amplitude Spectrum: When the phase factor φ_1 = 0, the long axis of the third-degree body coincides with the x-direction. 1) When θ = 0 or D = (π / 2), the change of angle θ does not affect the amplitude The symmetry of the spectrum only affects the amplitude value, the smaller the value of θ is, the smaller the amplitude value is; 2) the amplitude value reaches the maximum when θ = (π / 2); 3) when Dm0 or Dm (π / 2) The changes affect both symmetry and amplitude values. the smaller the θ is, the worse the symmetry is and the smaller the amplitude is. 4) When b = c, D changes from 0 to (π / 2), and the equivalent coil in the amplitude spectrum extends in one direction. When b = c, the extension of the equivalent coil in the amplitude spectrum is the same as that of b = c. In the case of the phase factor φ_1m0, the major axis of the third-degree body does not coincide with the x-direction. In this case, as long as a coordinate transformation is made, the amplitude spectral pattern is the same as that of φ_1 = 0 in the new coordinate system. Phase spectrum: When the phase factor φ_1 = 0 and the displacement factor x_0 = y_0 = 0, the center of the third-degree body is located just below the origin of the coordinate, and the contour of the phase spectrum is a series of radial straight lines originating at the origin; when x_0m0 and y_0m0 , The phase spectrum changes periodically, but the same pattern as x_0 = y_0 = 0 can still be obtained as long as the appropriate conversion is made. In the case of φ_1m0, coordinate transformation is still performed according to the amplitude spectrum, and the same pattern as φ_1 = 0 can be obtained. According to the above characteristics of the amplitude spectrum and the phase spectrum, the magnetization tilt θ and the magnetization deflection D can be determined.