Automated Locating Mining-Induced Microseismicity without Arrival Picking by Weighted STA/LTA Traces Stacking

Abstract

The automatic location of the microseismic source is still a challenging endeavor in the microseismic field. Due to the complexity of the mining environment, the microseismic records collected by different channels vary, and generally have a low signal-to-noise ratio (SNR). Therefore, the automatic location algorithm is required to be robust and accurate. For microseismic records with low SNR, the stack-based method does not need to pick arrival, thus avoiding the large location error caused by picking arrival. However, the traditional stack-based method does not consider the influence of the waveform quality of different stations, which can bring some errors to the location result. In this paper, in order to improve the location accuracy of the traditional stack-based method, we propose a method for weighted STA/LTA traces stacking. First, we established evaluation indicators of waveform quality based on microseismic records. Then, the STA/LTA traces are given weight to stack according to the evaluation indicators. Finally, the maximum value of the stacking function is solved in the four-dimensional space to obtain the source coordinates. In the process of calculation, we use the weighted differential evolution (WDE) optimal algorithm instead of the full grid search method, which greatly improves the calculation efficiency. The blasting experiment and engineering application show that the proposed method is stable and effective, and the location accuracy is higher than the traditional stack-based method and the arrival-based method.

Waveform Complexity and Positioning Analysis of Acoustic Emission Events during the Compression Failure Process of a Rock Burst Prone Sample

“…The quality of the original waveform directly determines the accuracy of event recognition and the method of picking up take-off points for event localization [43]. Some algorithms are helpful in improving the quality of the original waveform [19,44], but the processing algorithm is bound to cause some changes in the original waveform, and the processing process is also a certain source of error. A better way is to obtain relatively clear take-off points and other information indicators without waveform processing and then use them for positioning [45].…”

A Novel Polarity Correction Method Developed on Cross Correlation Analysis for Downhole Migration-Based Location of Microseismic Events

“…Gajewski et al and Rentsch et al built the characteristic function based on squared amplitudes in the location process [15,16]. Subsequently, the STA/LTA based on the squared amplitudes was used to construct the characteristic functions for the purpose of phase identification and source location [17][18][19][20][21][22][23][24][25]. Baker et al, Gharti et al and Li et al converted the raw waveforms to positive amplitudes by using the envelopes of seismograms in the imaging process [26][27][28].…”