关键词: 微震, 定位算法, 倾斜地层, 速度模型, 传播路径

Abstract: The velocity model is significant for precisely locating the earthquake source in inclined strata. This study analyzed the propagation path and propagation regularity of stress waves in inclined strata, according to the fast ray-tracing technique between two points in horizontal layered media. Microseismic location algorithm was developed for inclined strata using grid searching method, which was also compared with traditional location methods based on single velocity model. The particle flow theory was exploratively used to establish the stratum numerical model. Subsequently, the validity of the proposed algorithm was verified by simulating the stress wave propagation through the interaction of particles. Results show that the traditional location algorithm, based on simplified elastic wave propagation at a constant velocity, is imprecise for inclined strata, indicating that the single velocity model cannot satisfy the locating demand for complex media., On the basis of the inclined layered velocity model and a modified computational method for stress wave propagation path, the seismic sources can be located much more accurately. Meanwhile, the location deviation was found to be proportional to the dip angle and stratum number. In addition, the location precision can be also increased by reducing the grid size in the grid searching method, suggesting that reasonable sizes and searching strategies can facilitate the application of grid searching method in practical engineering. The microseismic location method and the proposed verification process can provide important theoretical and technical support for further studies on the positioning and monitoring technology in the complex strata.

Key words: microseism, location algorithm, inclined strata, velocity model, propagation path