Travel time calculation of seismic waves on complex surfaces using the group marching method

Seismic travel time is a crucial parameter for describing the kinematic characteristics of seismic waves, significantly influencing the accuracy and computational efficiency of various seismic data processing techniques. A travel time field must be obtained accurately for numerous seismic processing algorithms, particularly in complex surface environments. Therefore, developing a high-efficiency and high-precision method for calculating seismic wave travel time that can accommodate complex surface models holds considerable research significance and practical value. This study introduces the group marching method (GMM) for determining the travel time of seismic waves under complex surface conditions. The GMM is built on the narrowband extension scheme of the standard fast marching method (FMM) and employs a novel iterative strategy. Moreover, it updates and computes a set of grid nodes within the narrowband, thereby enhancing the algorithm's computational efficiency. To evaluate the performance of the GMM algorithm, a complex surface velocity model frequently encountered in seismic exploration is used. Its performance is compared with that of the FMM algorithm. Results indicate that the GMM algorithm's calculations align with the propagation laws of seismic waves under complex surface conditions. While the accuracy of the GMM algorithm is comparable to that of the FMM algorithm, its computational efficiency is three times greater.