An accurate microseismic (MS) source location method is the foundation of MS monitoring technology for stability analysis of rock mass

and the first-arrival travel time calculation method is one of the important factors determining the precision of MS source location. An improved linear interpolation algorithm based on the fast marching methods (FMM) and LTI ray tracing is introduced to obtain relatively accurate first-arrival travel time in complex rock masses. Moreover

this improved algorithm is verified by the uniform velocity model and the Marmousi model. On the basis of travel time calculation

Runge-Kutta method

a single-step high-precision method in the numerical algorithm of ordinary differential equations

is introduced to calculate the ray propagation path. Besides

its rationality is verified in the uniform

stratified and hollow rock mass model established by us. Finally

using the least-squares method as the objective function

the MS source location is achieved by obtaining the optimal node that makes the objective function taken the minimum value. In the Marmousi model with underground caverns established by us

the location errors for the pre-set source points are 1.41

1.00

2.83

1.41 m and 1.41 m

respectively. It is verified that the method in this paper can achieve relatively accurate location in the complex rock mass and provide a new idea for improving the accuracy of microseismic location in the engineering rock mass.