New Zealand straddles the volatile boundary between the Pacific and Australian plates. This tectonic marriage means our mountains, valleys and coastlines are always on the move – sometimes slowly, sometimes in sudden lurches. For decades, scientists relied on ground‑based instruments to measure these shifts. Today, we are using a combination of radar satellites and clever mathematics, to monitor the land movements... even from hundreds of kilometres above. InSAR land-movement

A satellite the size of a small car can spot the ground beneath it shift by less than the width of a fingernail. Interferometric Synthetic Aperture Radar (InSAR) does this by comparing the phase of microwave echoes recorded on repeat satellite passes; any change in path length shows up as coloured fringes that can be converted into millimetres of motion. Because radar works through cloud and in darkness, the technique delivers truly all-weather ground-deformation maps, turni

The recent landslide in Papua New Guinea has brought to light the importance of effective landslide detection and prevention systems. A composite image depicting the stages of satellite-based landslide monitoring and data processing This catastrophic landslide, which occurred in the remote village of Kaokalam in the Enga Province, buried as many as 2,000 people under rubble and debris. Described as being as large as four football fields, struck at around 3 a.m. local time, t