Abstract:Micro-seismic source location is crucial for the micro-seismic monitoring technology. The existing algorithms usually minimize the function of time arrival values(time difference) from all detectors to obtain the location of micro-seismic source. The positioning results deviate usually from the actual locations of the sources because all the known micro-seismic parameters have errors. To overcome the shortcomings of the present algorithm,a two-step inversion method for the micro-seismic source location is thus proposed. The first inversion is to identify the abnormal detector,and the second inversion is to search the exact location from the space coordinates of sources. The 3–parameter,4–parameter and 5–parameter inversion models on the assumption of uniform velocity are established and compared. A multi-objective genetic algorithm(Non-dominated Sorting Genetic Algorithm–II,NSGA–II) is used for the first inversion. A single objective optimization algorithm is suggested in the second inversion in order to achieve the accurate source searching and to reduce the computing time. The results from a case study indicate that the proposed method can effectively identify the abnormal detectors and the positioning is greatly improved compared with the results with the abnormal geophone. The 4-parameter inversion model is better than the 5-parameter inversion model.
GEIGER L. Probability method for the determination of earthquake epicenters from the arrival time only[J]. Bulletin of St.Louis University,1912,(8):60-71.
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