Abstract:
The traveltime and ray path of seismic waves are key parameters in seismic data processing, and the accuracy, efficiency and stability of their calculation directly affect the imaging accuracy and analytical capabilities of seismic waves. However, traditional algorithms exhibit deficiencies in computational efficiency and accuracy. To address these deficiencies, a ray tracing method based on Multipoint Spline Traveltime Interpolation (MSTI) is introduced. Theoretical calculations and analyses show that the traveltime curve obtained through the MSTI method closely matches the actual traveltime curve, significantly outperforming traditional approaches such as Linear Traveltime Interpolation (LTI) and Parabola Traveltime Interpolation (PTI). In numerical simulation, both uniform and vertical gradient velocity models are constructed. The results indicate that: ① The traveltime calculated using the MSTI method is closer to the theoretical traveltime, and even with fewer nodes, the computational accuracy surpasses that of the LTI method; ② When the number of interpolation nodes at the element boundaries is the same, calculation accuracy improves as the discrete elements are refined; ③ When the size of the discrete element is fixed, increasing the number of nodes significantly enhances the traveltime accuracy of the MSTI method, while the improvement in the LTI method accuracy is marginal; ④ In the vertical gradient velocity model, the traveltime calculated using Snell's law is closer to the theoretical traveltime, and increasing the number of nodes significantly improves the accuracy of the MSTI method, while the improvement in the LTI method accuracy tends to stagnate. To further verify validate the effectiveness of the MSTI method, a comparative analysis of inversion results for different anomalies is conducted. The tomographic imaging technique based on the MSTI method accurately locates different anomalies, demonstrating the method's superiority. Field test results indicate that the inversion of velocity anomalies using the 2.5D curved ray tracing tomographic imaging algorithm based on the MSTI method closely matches the spatial positions of the faults exposed during mining practice, providing robust technical support for the safe and efficient production of coal mines.