Two‐dimensional Harmonic Analysis as a Tool for Magnetic Interpretation

Abstract

The total magnetic field values over an area can be represented exactly by a double Fourier series expansion. In this analysis, such an expansion is used to evaluate very accurately the fields continued downward and upward from the plane of observation and the vertical derivatives of the total field. This harmonic expansion of the anomalous total field makes it possible to calculate, with exceptional accuracy, the field reduced to the magnetic pole and its second derivative. The results of the calculations are free from the effect of the inclination of the earth’s main geomagnetic field and that of the polarization vector, at all magnetic latitudes and for all possible directions of polarization. In order to determine the influence of remanence on the above field, a number of anomalies caused by rectangular block‐type bodies with known polarization are reduced to the magnetic pole, correcting only for the obliquity of the earth’s normal field. It is concluded from a study of these anomalies that the interpretation of magnetic data based on the assumption of rock magnetization due solely to induction in the earth’s field may yield erroneous results, particularly when remanence is important.

The Assessment of Geothermal Potential of Turkey by Means of Heat Flow Estimation

“…Günümüz co¤rafyas›nda yer alan farkl› jeolojik zamanlarda oluflmufl havzalar›n da manyetik temel derinli¤inin ve konumunun ortaya ç›kart›lmas›n›n yan› s›ra maden, jeotermal, petrol araflt›rmalar› gibi pek çok konu için bilgiler içerir. Bhattacharyya (1965Bhattacharyya ( , 1966, Spector ve Bhattacharyya (1966) potansiyel alan verilerinin yorumlanmas›nda, istatistiksel bir yaklafl›m olan güç spektrumu yöntemini kullanm›fllard›r. Güç spektrumu yöntemi ile manyetik belirtiye neden olan yer alt› yap›lar›n›n derinliklerini belirlemek mümkündür (Spector ve Grant, 1970 Ayd›n vd., (2005), 1x1 km grid yapt›klar› haritalar›n› 380 adet blo¤a bölerek spektral analiz tekni¤ini her bir blok üzerinde uygulam›fllard›r.…”

Use of magnetic surveying in landslide analysis at the boundary between the granite

“…However, the residual magnetic anomalies that are used to determine the underground magnetic structure are sometimes difficult to determine using this method. The RTP method was considered to be an effective method for solving this problem (e.g., Bhattacharyya, 1965;Makino, 1993). Details of the RTP method are provided by Baranov (1957) and Baranov and Naudy (1964).…”

Global nonlinear optimization for the interpretation of source parameters from total gradient of gravity and magnetic anomalies caused by thin dyke

“…2001], Fourier transform [Odegard and Berg 1965, Bhattacharyya 1965, Sharma and Geldart 1968, Euler deconvolution [Thompson 1982], Mellin transform [Mohan et al 1986], Hilbert transforms [Mohan et al 1982], least squares minimization approaches [Gupta 1983, Silva 1989, McGrath and Hood 1973, Lines and Treitel 1984, Abdelrahman 1990, Abdelrahman et al 1991, Abdelrahman and El-Araby 1993, Abdelrahman and Sharafeldin 1995a, Werner deconvolution [Hartmann et al 1971, Jain 1976, Kilty 1983; Walsh Transformation [Shaw and Agarwal 1990], Continual least-squares methods [Abdelrahman and Sharafeldin 1995b, Abdelrahman et al 2001a, b, Essa 2012, Euler deconvolution method [Salem and Ravat 2003], Fair function minimization procedure andAsfahani 2011a, Asfahani andTlas 2012], DEXP method [Fedi 2007], deconvolution technique [Tlas and Asfahani 2011b]; Regularised inversion [Mehanee 2014, Mehanee andEssa 2015]; Simplex algorithm [Tlas and Asfahani 2015], simulated annealing methods [Gokturkler and Balkaya 2012], Very fast simulated annealing Acharya 2016, Biswas andSharma 2016a, b;Biswas 2015, b, Sharma and Biswas 2013a, particle swarm optimization [Singh and Biswas 2016] and Differential Evolution ] have been used to solve similar kind of no...…”