A strategy for magnetic data interpretation in South China Sea

Abstract

Directly interpreting total-field magnetic anomaly data in the South China Sea (SCS) can be difficult because of the complex patterns associated with low-latitude anomaly projection and the presence of remanent magnetization. Additional difficulty arises from the fact that the ambient field direction, thus, the total-field anomaly projection direction, varies over a wide range in the area. To alleviate these difficulties, we present a strategy by using magnetic amplitude data analyses and inversion. Equivalent source processing is used to calculate the amplitude data in the space domain since the wavenumber-domain method is no longer applicable due to low and highly variable inclination. The amplitude data serve the role of reduction-to-pole (RTP) transformation for structural interpretation. We then carry out the amplitude inversion to generate a 3D subsurface distribution of effective susceptibility. The inversion results show that this approach is feasible and effective in SCS.