Model field computations of vertical magnetic anomalies due to 2D fault sources bounded by non-planar fault planes

Abstract

Listric faults are curved normal faults in which the fault surface has concave upwards because the main detachment fracture follows a curved path rather than a planar path. These faults are formed during rifting, drifting, and evolution of passive continental margins, naturally associated with basinal development. Knowledge of listric faults helps not only in evaluating commercially viable natural sources but also in addressing a variety of geodynamic problems including seismic risk studies. However, the curvature of listric faults does not allow any accurate estimate of the extension from surface observation of dip and throw of the faults and so, major extension cannot easily be estimated by surface mapping alone. On the other hand, the detached rock masses on either side of such fault planes may create lateral contrasts in subsurface distribution of rock magnetizations and, accordingly, could generate detectable magnetic field anomalies across the fault planes. In this study, a comparison has been made between the magnetic field responses of a 2D fault source, presuming both planar and non-planar surfaces for the fault planes.