![]() ![]() The land shifted both sideways and vertically each side of the rupture, the changing topography forming a brand new wetland that’s already attracting waterbirds. This formerly flat, straight railway line illustrates the massive displacement caused when the Kekerengu Fault split to the sea. New Zealand’s historical record is short-we’ve had only a handful of really large earthquakes since records began in the 1800s-so figuring out their patterns relies on this kind of ‘palaeo-seismic’ research. They have both spent their professional lives trying to understand a handful of connected faults that score Marlborough and North Canterbury’s farms and river valleys to infer from faint echoes left in the landscape what happens when they detonate in sudden movement. Though Van Dissen works for GNS Science and Little for Victoria University, they’ve been best friends since they met while making a similar trench on the Awatere Fault two decades ago, sharing a taste for beer and music around the campfire at the end of a day’s work (Van Dissen on guitar, Little on harmonica). They cut down through the earth in a series of steps, taking soil samples from the walls, until they were four metres below the surface in a muddy hole at the heart of the fault. Their team spent several weeks in the field, tracing the fault’s story into the past. Last summer, earthquake geologists Russ Van Dissen and Tim Little dug a 15-metre-long trench across a paddock on North Canterbury’s Kekerengu Fault, hoping to answer a question that had long eluded scientists: how often did it rupture, and how far did it slide when it did? They suspected it was one of the fastest-moving faults in the country, and new dating techniques gave them a chance to find out for sure. “Instead of it being Russian roulette, you can wear a helmet.” “To be able to predict an earthquake you’d need to know a whole lot more than we do now about how these processes work.” So is anywhere in New Zealand safe? Not really, he says, but there are things everyone can do to prepare. Could we have seen it coming? Science is still a long way from being able to forecast earthquakes, says GNS earthquake geologist Russ Van Dissen. Roads and hillsides subsided without warning in those few minutes in the middle of the night. Written by Kate Evans Photographed by Rob Suisted ![]()
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