Wigner distribution based phase-only correlation

Identifications of similar seismic events are needed for locating source position and evaluating the subsurface structure from passive micro-seismic data. Phase-only correlation (POC) is used to measure similarity of waveforms and there are three key steps for the implementation: 1). Transform original data into time-frequency domain by shorttime Fourier transform (STFT); 2). Calculate the POC function based on time-frequency data; 3). Estimate the similarity of waveforms by the peak value of POC function. However, the low resolution of STFT limits the performance. To overcome this drawback, we propose an improved POC method by using Wigner distribution to replace STFT and we name it WPOC in this paper. We apply WPOC to both synthetic and field data. The comparison of results obtained by POC and WPOC clearly show that the proposed WPOC is more effective than POC for evaluating similarity of waveforms.