Crustal structure beneath the western Hubei Province of China from joint inversion of ambient noise and receiver functions

Abstract:

We investigate crustal S-wave structure beneath the western Hubei Province, which is located at a topographic step in China with high-rising plateaus to the west and low-elevation plains to the east. We collected two-year continuous seismic waveform records of 22 permanent broadband stations and six-month records of 29 portable stations and did cross-correlations of the waveform data between stations. We then measured phase/group velocity dispersion curves from 8 to 35s using frequency-time analysis (FTAN) method and performed surface wave tomography using the fast marching method to obtain phase/group velocity maps. We finally constructed high resolution 3-D shear-wave velocity structure beneath the western Hubei Province from joint inversion of surface wave dispersion data and receiver functions. The 3D model shows shear velocity variations are well correlated with geological features, such as sedimentary basins and mountain ranges. In particular, a high velocity anomaly beneath the Three Gorges Reservoir Dam indicates that it is located in a tectonic stable region.