Research on Microseismic Arrival Time Picking Method Based on VMD and CUSUM

The complex environment in metal mines introduces substantial noise into microseismic signals, which reduces the accuracy of arrival time picking and affects source localization. When the Cumulative Sum (CUSUM) method is directly applied, it often leads to inaccurate arrival time picking with low precision and high false alarm rates. To address these limitations, this paper proposes a novel arrival time picking method (V-CUSUM) that combines Variational Mode Decomposition (VMD) with the CUSUM algorithm. The microseismic signal is first decomposed into band-limited intrinsic mode functions (IMFs) using VMD with fractal box dimension-optimized parameters (K = 5; α = 2000). Effective IMFs are selected based on the Pearson correlation coefficient (threshold: |r| > 0.5), and the CUSUM method is independently applied to each selected component for arrival time detection. The final arrival time is determined by averaging the individual picking results. Simulation experiments demonstrate that the proposed method achieves a root mean square error (RMSE) of 0.0024 s and a mean absolute error (MAE) of 0.0018 s, substantially outperforming the Short-Term Average/Long-Term Average Method (STA/LTA) (RMSE = 0.0347 s) and Akaike information criterion, AIC (RMSE = 0.061 s), methods. Validation with field microseismic data from a metal mine shows that V-CUSUM achieves an average picking accuracy of 99.86% with a standard deviation of 0.007 s, compared with 97.85% for STA/LTA and 99.58% for AIC. These results confirm that the V-CUSUM method provides a robust, accurate, and physically interpretable framework for microseismic arrival time picking under complex noise conditions.