Abstract
Cross-correlation methods for seismic event location utilize the differential travel time of the signals presented in the cross-correlation records for positioning, eliminating the necessity for scanning the earthquake occurrence time, thereby ensuring efficient calculation of event locations. The finite-frequency characteristics of the signal can cause a decrease in the time resolution of the correlation recordings, resulting in a decrease in the spatial resolution of the location. Exploration of various combinations of station pairs, often referred to as imaging conditions, have been commonly employed to enhance the positioning resolution. Instead of modifying the imaging conditions, we developed a dynamic time warping-based cross-correlation method aimed at enhancing the time resolution of the cross-correlation records. This innovative approach utilizes the Pearson correlation coefficient as a distance metric to conduct a global search to obtain time shifts for different seismic signals, providing an optimal correlation coefficient. The proposed workflow enables the transformation of the differential time and the Pearson correlation coefficients into high-resolution cross-correlation records. It not only enhances the time resolution of individual seismic event cross-correlation records but also captures the time differences of distinct signals across multiple events. Simulations show that the proposed method markedly improves both the time resolution of cross-correlation records and the spatial resolution of locations, effectively handling multievent locations with varying magnitudes. A case study reveals that the new method is effective in handling complex waveforms from regional seismic networks and serves as a significant improvement in the precision of seismic event location.
Published Version
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