Main Influencing Factors for the Accuracy of Microseismic Source Location

The microseismic source location is one of the most important and foundational parameters in seismic analysis. The positioning accuracy directly affects the results of the microseismic results. The influencing factors for the accuracy of the microseismic source location, including the station error, the velocity error and the error caused by the optimization algorithm, are analyzed and discussed. The source location and the number of source events are determined by an optimization algorithm, and the source coordinates vary greatly with the use of different algorithms. It is important to select a reasonable optimization algorithm with a high accuracy. The famous optimization algorithms, such as the Levenberg-Marquardt Method (LM), the Simplex Method (SM), the Quasi-Newton Method (QN), the Max Inherit Optimization (MIO), the Self-Organizing Migrating Algorithms (SOMA), as well as the Global Optimization (GO) coupled with MIO, QN, MIO and LM, were used to locate and compare the seismic source coordinates. Results show that it is easy to be trapped into a local optimum value using MIO, QN and LM alone. Therefore, the selection of MIO, QN and LM should be careful. The joint use of the global optimal algorithm combined with MIO, QN and LM can significantly improve the positioning accuracy. The SOMA, SM coupled with GO, the MIO coupled with GO and the LM coupled with GO, which are more stable with a high positioning accuracy, should be the recommended methods to locate the seismic or acoustic emission source coordinates.