A Database of Teleseismic Shear-Wave Splitting Measurements for the Ordos Block and Adjacent Areas

Abstract

Abstract The Ordos block of the north China craton and its surrounding regions are affected by the India–Eurasia collision to the southwest and the subduction of the Pacific beneath the Eurasian plates to the east. To provide the foundation for delineating lithospheric deformation and asthenospheric flow beneath this tectonically diverse region, we have created a database of individual shear-wave splitting (SWS) parameters by applying a uniform set of data processing procedures. After automatic data processing and manual checking, a total of 16,228 pairs of well-defined PKS, SKKS, and SKS splitting parameters (fast orientations and splitting times) are obtained from 1023 broadband seismic stations that recorded data between 2007 and 2019. Along the western and southern margins of the Ordos block, the observed seismic anisotropy is attributable to mantle flow deflected by the relatively thick lithospheric root of the Ordos block. A clear back-azimuthal dependence of the fast orientations is observed at some of the stations located in the Alxa block, Ordos block, and Sichuan basin, indicating possible existence of complex anisotropic structures. The new SWS database can be employed by researchers in various fields to study lithospheric deformation and asthenospheric flow beneath the Ordos block and surrounding regions.