Hamling, I.J.; Massey, C.I. 2023 Identifying anomalous ground deformation across Wellington. Lower Hutt, N.Z.: GNS Science. GNS Science report 2023/49. 20 p.; doi: 10.21420/1RCD-VJ30
Abstract
Deformation of the ground surface can pose risk to life, property, infrastructure and cultural sites; however, measuring this deformation over large regions is time-consuming and expensive. This project aimed to exploit high-resolution InSAR data over the Wellington region to investigate whether we can identify anomalous areas of ground movement, quantify the rate and temporal evolution and classify the likely processes causing the movement. Prior to the analysis and classification of the deformation, we find that separating the displacement data based on ground-cover class greatly improves the identification deformation hotspots and minimises false negatives. Using two independent methods, we successfully identify and isolate deformation hotspots across the Wellington urban area. In most cases, deformation is correlated with ground type, with a general focusing in areas of reclaimed land and anthropogenic fill. In addition, we have successfully managed to extract and isolate short-term deformation transients commonly associated with construction zones. With frequent updates to the deformation time-series in the future, InSAR now presents an opportunity to track not only long-term deformation but also short-term changes that may pose a hazard to local infrastructure.
