A hybrid microseismic source location algorithm based on simplex and shortest path ray tracing

Source location accuracy is the most important index to evaluate the microseismic monitoring effect.The shortest path ray tracing method is often used to solve seismic wave travel time field and source path under complex velocity model.It is an important forward modeling method for seismic wave travel-time calculation.In this study, this method is introduced into the field of mine microseismic monitoring, and a simplex-shortest path ray tracing hybrid localization algorithm has been established by combining with the conventional simplex localization method.Firstly, the shortest path ray tracing method is used to calculate the reverse ray path and travel-time from each detection point to the potential source point in the observation system.Then, a simplex algorithm is used to obtain an initial location based on the uniform velocity model.Finally, in a cell of the initial location, the sum of the difference between travel-time and backward time of each node is calculated.The node with the minimum sum value is taken as the source location.Numerical simulation results of the layered velocity model and the cavity velocity model show that the source path calculated by the shortest path ray tracing method conforms to the seismic wave propagation law.Based on the case of No.31101 longwall panel of Shendong mine, the location error of the new method is 4.35 m, and that of the conventional simplex method is 19.63 m.This method can provide important theoretical and technical support for the microseismic monitoring of complex strata such as stratigraphy and cavity-containing areas.