Abstract:
Firstly, 1 017 earthquakes provided by Sichuan Seismological Bureau are relocated, and 578 earthquakes with high signal-to-noise ratios after relocation are used as templates. The continuous waveform data recorded by 7 stations of Zipingpu reservoir seismic network from 2005 to 2008 are scanned by GPU-based match and locate (GPU-M&L) method. Then, based on the denoising results by applying the deep learning algorithm called DeepDenoiser, a convolutional neural network model is designed to further verify these newly detected events. Finally, the double-difference location method is used to accurately relocate them. A total of 16, 836 events are eventually identified, which is about 13 times as many as the events listed in the local catalog. The magnitude of completeness is reduced from
ML1.4 given by the local catalog to
ML−0.1. The relocated results show that the seismic events in the study area are linearly distributed in the northeast direction. The dominant focal depth indicates the location of the detachment layer in the crust of the region. Combined with the analysis results of
b value and the focal depth, it is speculated that the earthquakes after impoundment in the study area are mainly natural seismic activities caused by the accumulation of tectonic stress, accompanied by the occurrence of reservoir-triggered seismicity.