To obtain the shallow 3-D S-wave velocity structure of Xiamen Island,we calculated the noise cross-correlation function of the vertical components of continuous ambient noise waveforms,observed by a temporary 50-station seismic array on Xiamen Island in 2019.Then,we extracted the Rayleigh wave phase velocity dispersion curves by the frequency-Bessel transform(F-J)method,inverted the 1-D S-wave velocity structures under the subarrays,and finally obtained the 3-D S-wave velocity model of 0～4 km depth for this region by interpolation.The results show that the S-wave velocity of Xiamen Island increases with depth,and the lateral inhomogeneity is obvious near the surface.The S-wave velocity at 0～1 km depth is mainly"high in the north and low in the south",which coincides well with lithology distribution.As the depth increases,the horizontal distribution of S-wave velocity gradually becomes a strip with good continuity and near-northeastward spreading.According to previous studies,we inferred that this phenomenon is related to folds and faults formed by compressions and extensions during different periods,and implies multiple tectonic movements and magmatic intrusions in Xiamen Island.The obvious velocity difference in the vertical section corresponds to the location of the fault zone in the study area.The results can provide a scientific basis for the study of tectonic evolution and the assessment of geological hazards in Xiamen Island.
维普
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