Abstract:The first-arrival traveltime tomographic inversion is the most widely used near-surface modeling method.According to the forward modeling operator in the inversion, the tomographic inversion based on the ray theory can be divided into two kinds of methods:based on the ray-tracing equation and based on the eikonal equation.In this paper, a detailed contrastive analysis of the two me-thods in terms of inversion accuracy and compu-tational efficiency are carried out respectively in theory and numerical tests.The following observations are obtained:①The two methods can be deduced from the unified inversion framework.The main differences between the two methods are caused by the differences of the forward-modeling operators in the inversion; ②The two methods have similar inversion accuracy.The kernel function of the second method is band-limited, so it is more stable in complex areas; ③The computatio-nal efficiency of the first method depends on the number of receivers and the second method depends on the size of the model.So the first method is preferable when receivers are sparse.Otherwise, the second method is preferred; ④The first me-thod has lots of quality controls such as ray density, while the second method lacks similar quality controls.
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