固物研究生论坛 - Shallow 3D shear wave velocity structure

Shallow shear wave velocity structure plays essential role in earthquake hazard assessment, seismic imaging and geodynamic simulation. However, for China, it remains poorly constrained due to sparse data coverage for traditional body wave and surface wave tomography methods. To resolve it, Rayleigh wave ellipticity or ZH ratio, mainly sensitive to local shallow shear wave velocity (Vsv) model, and P wave receiver function (PRF), reflecting discontinuities, are used to jointly constrain the shallow Vsv structure extending to 8 km from surface with a Markov Chain Monte Carlo (MCMC) method in this study. As a result, this study results a pseudo 3D Vsv model beneath China extending to 8 km, highly correlating with geological features, which identifies location, shape and sediment thickness of Sichuan basin, Bohaiwan basin, Songliao basin, Ordors block and Subei Yellow Sea basin, Chuxiong basin and Lanping-Simao basin. In addition, this study generates a byproduct–nearsurface shear wave speed structure, which partly reflects average shear wave velocity among depth from free surface to several kilometers beneath China.