Geologists map rupture

While the magnitude 7.1 Canterbury earthquake was an event most people would not like to repeat, it represented a "once-in-a-lifetime" opportunity for geologists.

It was standing room only at the Quad Two lecture theatre at the University of Otago, as more than 200 people attended a lecture to hear first-hand accounts of the earthquake's epicentre - the 22km-long rupture trace.

Institute of Geological and Nuclear Sciences (GNS) geologist Dr Richard Jongens flew over the rupture trace on Saturday, after it was located by University of Canterbury geology lecturer Dr Mark Quigley.

"It was a once-in-a-lifetime opportunity," he said.

As media focused on the damage caused to Christchurch and surrounding areas, the three Dunedin-based GNS staff worked to document the fault from the air - before farmers ploughed the land and contractors levelled roads.

The 22km fault, which runs across farmland stretching from Greendale (in the west) to Rolleston (in the east), caused only minor damage to a handful of buildings, power lines to become taut, and roads to be thrown out metres.

Dr Jongens said the area represented exactly what they try to replicate in the geologists' sandbox experiments. "It was a textbook example."

Also documenting the rupture trace on the ground was University of Otago geology lecturer Dr Virginia Toy, who said the earthquake represented a "once-in-a-lifetime chance" to gather teaching material for her students.

Both geologists agreed the earthquake had raised interest in geology, with many people asking them what are the chances a similar quake could strike here.

"The amount of ground-shaking that happened in Christchurch - we can't say that won't happen here in our lifetimes," Dr Toy said.