Mapping Earth's Crustal Structure of the Eastern Vietnam Continental Margin from Gravity Anomalies: Implication for oil and gas distribution

Abstract To address the limitations in deep seismic research on the Vietnamese continental margin, this study utilized high-resolution marine satellite gravity data, alongside sediment thickness and bathymetry data. Applying Parker's (1972) 3D inverse method, we developed a crustal structure model of the eastern Vietnamese continental margin. Interpretation revealed Moho depths ranging from 8.5 km in the Southwest Sub-basin to 29–30 km in the coastal zone, demonstrating an average error of 9.6% compared to OBS data. Basement depths varied from 2.5 km near the Hoang Sa Archipelago to 12.5–13.5 km in the Red River Basin, with a 6.2% average error compared to OBS data. Consequently, the derived crustal thickness map showed significant variations, from 4–6 km in the Southwest Sub-basin to 25 km in coastal areas. Major NW-SE, NE-SW, and N-S fault systems were also identified using the maximum horizontal gradient method and its derivative. Based on modern rifted continental margin models, six distinct crustal domains were zoned, and importantly, their distribution showed a strong correlation with known oil and gas fields, affirming the pivotal role of Earth's crustal structure in controlling hydrocarbon potential.