Transformação de estimativas suaves aplicadas à interpretação de relevos descontínuos do embasamento

Abstract

We present a method to delineate the basement relief of sedimentary basins composed by vertical faults and horizontal plans. We assume density contrast between the basement and the sediments constant or decrease with depth, and known. The developed method determines the vertical positions for horizontal plans and horizontal positions for vertical faults through an smooth initial solution of the basement relief. We produce this smooth solution through an efficient method which delineates the smooth basement relief. The horizontal positions of two adjacent faults estimates the extension of only one horizontal terrace. Similarly, the vertical position of two adjacent horizontal terraces estimates the extension of the fault between them. The performance of the proposed method is compared with the computational time of two other inversion methods, which stabilize the solution applying the Total Variation functional. The proposed method always produced solutions in less computational time as compared with the computational time required by other methods. Tests on synthetic data contaminated with zero-mean Gaussian pseudorandom noise with a standard deviation of 0.1 mGal show which proposed method produced satisfactory results and estimated basement topographies close to simulated basement topographies. The proposed method was applied to two sets of real Bouguer anomalies: Steptoe Valley (United States) and San Jacinto Graben (United States). The method produced estimated basement topographies presenting high-angle faults in accordance with the available geological information, which the basins above mentioned were formed by extensional tectonics with the consequent formation of structural settings of sedimentary basins conditioned by normal faults.