Integration of Heterogeneous InSAR Measurements for Mapping Complete and Accurate Three-Dimensional Surface Displacements: A Case Study of 2016 Mw 7.8 Kaiköura Earthquake, New Zealand

Three-dimensional (3-D) deformation fields associated with the 2016 Mw 7.8 Kaiköura earthquake in New Zealand are retrieved from SAR data acquired by ALOS-2 descending and Sentinel-1 ascending orbits based on the Pixel OffsetTracking technique In particular, a recently proposed method SM-VCE (Strain Model and Variance Component Estimation) is exploited to integrate the heterogeneous InSAR observations. The core idea of this method is exploiting the spatial correlation of the homogeneous points' deformations based on strain model, and determine the exact weights for the heterogeneous InSAR measurements by employing variance component estimation algorithm. The results reveal that the presented SM-VCE method is capable for the retrieval of complete and accurate 3-D deformation fields with respect to this event, which are highly consistent with the GNSS observations. In addition, accuracies of the used heterogeneous InSAR observations as well as the estimated 3-D deformations are quantitatively provided by the presented SM-VCE method.