One-Dimensional Electrical Sounding and Semi-Automatic Inversion

One-dimensional electrical sounding and semi-automatic inversion is a data processing method used in direct current (DC) resistivity surveys, primarily for detecting subsurface resistivity distribution. This approach measures apparent resistivity data at different electrode spacings on the surface and uses inversion algorithms to deduce the resistivity structure of underground media.

### Basic Workflow Data Acquisition: Measure apparent resistivity at varying electrode spacings using DC sounding configurations (e.g., Wenner, Schlumberger arrays). Forward Modeling: Compute theoretical apparent resistivity curves based on a layered resistivity model, typically implemented using recursive algorithms like those from Wait or Koefoed to handle layer interactions. Inversion Optimization: Apply semi-automatic inversion algorithms (e.g., Least Squares, Levenberg-Marquardt) to adjust model parameters, minimizing residuals between theoretical and field data through iterative gradient-based optimization.

### Semi-Automatic Inversion Features Human-Computer Interaction: Allows manual adjustment of initial model parameters (e.g., layer thicknesses/resistivities) to guide convergence and enhance reliability. Efficient Convergence: Optimization algorithms reduce computational load via Jacobian matrix approximations and damping factors, accelerating convergence to optimal solutions. Broad Applicability: Suitable for analyzing subsurface resistivity structures in hydrogeology, engineering surveys, and mineral exploration.

### Application Scenarios Groundwater Exploration Karst and Fault Detection Mineral Resource Investigation

This method significantly improves inversion accuracy while reducing manual computation efforts, making it applicable to diverse geological exploration tasks. Key functions often include resistivity-to-depth transformation routines and sensitivity analysis modules to evaluate model robustness.