<p>Layer-wise parameters.</p>

Under a signal-to-noise ratio (SNR) of 5 dB, the proportions of samples with start and end point detection errors falling within the 0–5 range were 79.98% and 89.93%, respectively. Compared with EQTP, SEU-Net achieved an initial F1 score of 88.88% and an intersection-to-union ratio of 79.98%, which are higher than EQTP’s 86.81% and 76.69%, respectively. The error distribution and various evaluation metrics indicate that SEU-Net can maintain high accuracy in event boundary detection even under noise interference.

Three-dimensional source localization based on the detection results shows that the spatial distribution of sources corresponding to SEU-Net is more concentrated and consistent with the actual fracture evolution process of the test specimen. This method provides technical support for the automatic detection of microseismic signals and source localization in complex rock mass engineering environments with low signal-to-noise ratios.</p></div>