Present-day crustal deformation based on an interpolated GPS velocity field in the oblique collision zone of the Arabia-Eurasia tectonic plates

Abstract This study utilized biharmonic splines to interpolate sparse GPS velocity data independently and in a coupled manner by altering Poisson's ratio. This method is an effective means of interpolating sparse vector data in cases where deformation mechanics can be explained by elasticity principles. The research focused on the oblique collision zone of the Arabia-Eurasia tectonic plates, where the GPS velocity field is sparsely distributed. The interpolation process included fitting trends to the input GPS velocity data, calculating residuals, and analyzing them using a biharmonic spline. The prediction process consisted of trend fitting and spline fitting stages. Interpolation methods were employed to interpolate horizontal GPS velocities onto a standard geographic grid with a 30-minute interval, excluding data points with significant deviation. The data was partitioned into training and testing subsets, with the training set used for calibration and the testing set for evaluation of the interpolation method. The article discusses the irregular spatial distribution of crustal movement in the collision zone. The northern component of the velocity field is greater than the eastern component and consistently points towards Eurasia. In the collision zone, the eastern component changes direction, moving westward in the western half of Iran and eastward in the eastern half, with a reversed trend in the north. This change in direction helps identify solid blocks, while the amplitude of the northern component decreases from south to north and from west to east. Undeformed regions, major faults, convergence deformation, and compressing high-elevation regions are also observed in the collision zone.