[SSS14-P19] Estimation of Deformation Fields from GNSS Data Using Basis Function Expansion: Comparison with the Method by Shen et al. (1996)
Keywords:GNSS, basis function expansion
As an alternative consistent method, we present a fitting of velocity fields using basis function expansion. On the estimation of crustal movements, Fukahata et al. (1996) developed a method to reconstruct time variation of vertical crustal movements using levelling data. We modify their formulation to estimate a 2D horizontal velocity field using GNSS data. Since the velocity field is represented by a linear sum of a finite number of basis functions, its derivative, i.e. the strain rate field, can be analytically obtained. A hyperparameter that controls the smoothness of the velocity field can be objectively determined from observed data using ABIC (Yabuki and Matsu'ura, 1992, GJI). In addition to these theoretical advantages, we practically demonstrate the characteristics and merits of this method compared with the method by Shen et al. (1996) by applying them to GNSS velocity data in Japan.