Regional noise source location based on the time delays between station pairs from ambient noise interferometry.

Identifying the location of a potential noise source assists in understanding the characteristics of the seismic or volcanic activity and provides valuable information for hazard assessment. Unlike the conventional waveform-based techniques that rebuild the source energy into the possible source region, we apply a simplified method to determine the absolute location of the noise source based on the station-pair time-delays from ambient noise interferometry. Synthetic tests demonstrate the robustness of the method and the locating precision is mainly influenced by the signal-to-noise ratio of the synthetic waveforms, and the higher frequency bandwidth source signals are more likely to result in accurate detection of the source. An application at the Central Tien Shan indicates that our method is capable of locating the known virtual source from the empirical Green's functions. Furthermore, assuming a surface wave velocity, the depth of the source can be generally recovered from ambient noise interferometry in a simplified 3-D homogeneous model. The new method sheds light on applications of ambient noise interferometry for locating potential sources, making it suitable for detecting time-dependent behavior.