Multimodes of Rayleigh wave excited by hurricane Dorian

英文摘要：

Extracting Empirical Green's Functions (EGFs) by cross-correlating ambient seismic noise or coda, considered as an efficient approach of retrieving new response inside the media of two receivers, has been developed well in the past two decades. However, EGFs emerge with high Signal-to-Noise Ratios (SNRs), which needs us to stack a large number of cross-correlations. Here, we retrieve EGFs with high SNRs from ambient seismic noise released by hurricane Dorian moving along the eastern coast of the United States during 3 days in Sept 2019. We systematically analyze the energy sources of seismic noise records with time-frequency analysis and beam-forming. We find that the energy exhibits very strongly when hurricane Dorian progresses along the coast from 4th to 6th Sept. Our results suggest that EGFs exhibit strong directionality and only emerge in the negative part of cross-correlation time functions due to the noise sources of Dorian. We extract clear multimodal dispersion curves of Rayleigh waves from retrieved EGFs. Our results, indeed, reveal that multimodal dispersion curves pf Rayleigh wave could be extracted from ambient seismic noise excited by Dorian for several days or even a single day, which means that we enlarge the seismic data sets for the future work of investigating shear velocity structures of the Earth's crust and upper mantle and understanding our planet more deeply.