This paper presents the effects of two factors on electrical resistivity tomography (ERT) resolution using numerical simulations. The results obtained from the first group of synthetic resistivity model numerical simulations with different electrode configurations illustrate that the inversion resolution can be improved if the current electrodes and potential electrodes are installed at a subsurface depth. The results obtained from the second group of synthetic resistivity models with different mesh densities illustrate that the inversion resolution can be improved if the mesh grid density is increased. The increased number of degrees of freedom necessary to fit the data to a prescribed target misfit leads to the inverted imagery deviating from the true resistivity model. Throughout the literature the inversion procedure is implemented in the conjugate gradient relaxation method and the model calculation speed is enhanced using the parallel processing mode. ERT surveys were employed for mineral exploration at Chifeng in Inner Mongolia, China. The inverted image clearly describes the vein behavior down to 200 m in depth in the prospect area and is consistent with the drilling data results

Improving efficiency and accuracy are critical issues in geophysical inversion. In this study, a new algorithm is proposed for the joint inversion of gravity and gravity gradient data. Based on the regularization theory, the objective function is constructed using smoothed L₀ norm (SL0), then the optimal solution is obtained by the non-linear conjugate gradient method. Numerical modeling shows that our algorithm is much more efficient than the conventional SL0 based on the sparse theory, especially when inverting large-scale data, and also has better anti-noise performance while preserving its advantage of high accuracy. Compressing the sensitivity matrices has further improved efficiency, and introducing the data weighting and the self-adaptive regularization parameter has improved the convergence rate of the inversion. Moreover, the impacts of the depth weighting, model weighting, and density constraint are also analyzed. Finally, our algorithm is applied to the gravity and gravity gradient measurements at the Vinton salt dome. The inverted distribution range, thickness, and geometry of the cap rock are in good agreement with previous studies based on geological data, drilling data, seismic data, etc., validating the feasibility of this algorithm in actual geological conditions.