A Canterbury University scientist has been surveying landslides to learn more about the physics that propels debris downhill.
Dr Liz Bowman was awarded a Marsden science grant to find out more about the mechanics of debris flows.
Her research is expected to improve the way the hazard is modelled.
She set up experiments using thick oil and glass pebbles and used lasers and fluorescent dye to see what was happening inside the mixture as it moved.
She found that debris composed of different size particles - for example, boulders, rock, pebbles and sand - travels faster and further than single material flows.
Dr Bowman says the study will feed into research that may one day allow the exact danger posed by known slip areas, to be quantified.