Friday Seminar: (Nov. 12th, 2021) Dr. Sanxi Ai (China University of Geosciences)

Lithosphere dynamics and deformation of the central North China Craton: Constraints from new seismic images

The North China Craton, which experienced distinct diachronous lithospheric thinning in the late Mesozoic and Cenozoic, provides a classic example of lithospheric reactivation to mantle upwelling in the world. In this talk, I will focus on the central North China Craton, which is a transition zone between the relatively stable Ordos Block and the Huabei Basin suffering from cratonic destruction. Firstly, I will talk about the techniques we used in imaging the crust and mantle structure, such as ambient noise tomography, array-based two plane surface wave tomography, and joint inversion of surface wave and receiver function. Then I will present the new seismic images derived from ambient noise and earthquake data, which help understanding the continental rifting and lithospheric modification in this region. Specifically, different rifting mechanisms between the southern and northern segments of the Fenhe-Weihe Rift is revealed by our isotropic and anisotropic images.