A refined hybrid method for 3D quaternary geological modeling and its application in coastal deposits

Abstract Refined 3D Quaternary geological modeling can reveal the spatial and geological structures of strata from a 3D perspective, which is an essential subject in current Quaternary geology and 3D GIS research. This research addresses the critical challenge posed by the significant discontinuity and heterogeneity of Quaternary strata, which result from multiple depositional events and lead to complex stratigraphic structures that are difficult to model accurately. To tackle this challenge, we developed the mDEM-GTP-TEN hybrid modeling method, integrating multi-layer digital elevation model (mDEM), generalized prism (GTP), and tetrahedral meshes (TEN) to achieve refined 3D models of Quaternary strata. This method incorporates virtual borehole data to generate multi-layer DEMs, constructs GTPs through vertical connectivity, and discretizes them into TENs, which serve as the fundamental voxels for 3D geological modeling. Additionally, validation tests conducted using geological parameters specific to Nantong City, a coastal region in eastern China, demonstrated the model's high accuracy. The results demonstrated an average error of 3.05 m for strata burial depth and 2.42 m for layer thickness, accounting for only 7.3% of the average layer thickness, confirming the model's effectiveness, reliability and accuracy in reflecting the spatial structure and geological architecture of Quaternary strata. The mDEM-GTP-TEN hybrid modeling method provides a robust theoretical and technical foundation for studying and mitigating geological hazards such as landslides, debris flows, and ground subsidence. By offering a more accurate representation of Quaternary strata, this model enhances our ability to predict and manage geological risks, thereby contributing to the advancement of Quaternary geology and 3D GIS applications.