Phase velocity tomography of Rayleigh and Love waves in Dabie-Sulu and its adjacent areasfrom ambient seismic noise

We used the same seismic data as the published paper “Love wave group velocity tomography in Dabie-Sulu and its adjacent areas from ambient seismic noise” by the author in 2014 and obtained more than 5 000 Rayleigh wave velocity dispersion curves and 4 000 Love wave phase velocity dispersion curves by frequency-time analysis (FTAN). Then, we constructed the Rayleigh and Love wave phase velocity maps at the period of 8—32 s. The results of Rayleigh wave is consistent with those of Love wave. The phase velocity maps at 8 s are well correlated with surface geological features. Orogenic belts and uplifts reveal high velocity anomaly, and the basins exhibit different levels of low velocity anomaly due to the different scales of deep sediments. The high velocity feature in the Dabie and Sulu regions becomes successively less prominent from 16 s to 32 s, but always exists. The high velocity anomaly from 16 s to 24 s may be controlled by the high velocity in the middle crust, while high velocity at 32 s may be influenced by the high velocity structure of uppermost mantle. The average dispersion curves of Love waves in Dabie and Sulu orogenic belts are all higher than the theoretical dispersion curves of AK135 model, whereas the dispersions of Rayleigh waves are not, possibly suggesting strong radial anisotropy in Dabie and Sulu orogenic belts.