Reconciling high-resolution strain rate of continental China from GNSS data with the spherical spline interpolation

In this study, we propose a new generation of high-resolution strain rate models for present-day continental China. The models were developed using up-to-date Global Navigation Satellite System (GNSS) observation data from 3571 stations. A spherical spline method was used to reconcile the sparsely distributed GNSS velocity data into an integrated regional spherical coordinate frame. The model simultaneously calculates the strain rate with an ideal order of continuity while preserving the discontinuity between tectonically active major fault zones and deforming blocks. Inspection standards were used to assess the validity and resolution of the proposed model. The spherical spline method was deliberately examined and the fitting to the GNSS velocity data was justified to illustrate the inspection standards. A spherical harmonic model was also constructed for the resolution tests. By introducing test criteria, the spherical spline method can reproduce the velocity and strain-rate fields in substantial order, indicating that the developed method has a high level of applicability for estimating the strain rate in active tectonic regions and for global models. Finally, the spherical spline method was used with the GNSS velocity data to calculate the strain-rate fields in continental China. The correlation between the seismic mechanisms and the strain-rate field of earthquakes was also assessed. The results indicate that the proposed high-resolution strain rate model could be used to explain the deformation and evolution models of continental China.