Nomograms for rapid evaluation of magnetic anomalies over long tabular bodies

A Graph Method for Interpretation of Magnetic Anomalies over 2D dikes and vertical faults

“…In the Figure 13a, the agreement between the observed and the calculated anomalies is good, and the recovered model parameters are similar to the values estimated in the previous studies of Qureshi and Nalaye (1978), Achuta Rao and Ram Babu (1981).…”

“…and Nalaye (1978), Achuta Rao and Ram Babu (1981). For the vertical fault data, the recovered parameters are compared to the mentioned previous studies in Table 3.…”

“…Similar to the dike case, the magnetic anomaly (ΔF) at any point P(x) on the profile due to a vertical fault may be given as, Rao and Ram Babu, 1981). Where, x is the distance of the observation point to the origin, z is the depth from surface to the half-thickness of the fault and t is the half-width of the fault.…”

“…For the implementation on the field data, the total magnetic field anomaly collected over the western margin of Perth Basin (Atchuta Rao and Ram Babu, 1981) is sampled with 2km intervals (Figure 13, solid line) and the sampled anomaly is decomposed into its even and odd components (Figure 13b). By the decomposition of this anomaly into its even and odd components, s=10,3 km is delineated from the abscissa of the half-maximum of the even component and the maximum of the odd component (Figure 13b).…”

“…Many researchers have been interpreted the anomalies of these structures by decomposing the anomalies into their origin-symmetric even and odd components. In Hutchison (1958) a logarithmic curve fitting method is implemented, in Bhimasankaram et al (1978) Fourier transforms are used, in Kara et al (1996) and Kara (1997) a method using correlation factors and integration nomograms is presented, in Rao et al (1973) two methods are presented using the horizontal derivative of the anomaly, and in Atchuta Rao and Ram Babu (1981) a method using nomograms is presented.…”