Major new fault found in NZ capital

A new geological fault capable of generating a magnitude-7.1 earthquake has been found in Wellington, confirming the New Zealand capital's status as one of the world's most seismically active cities, scientists revealed on Wednesday.

Geologists from the official National Institute of Water and Atmospheric Research said the Aotea fault began on the floor of Wellington Harbor and was believed to extend through the central city and southern suburbs.

NIWA marine geologist Philip Barnes said there was evidence that the most recent earthquake caused by the fault occurred about 6,200 years ago, and it was impossible to know if another temblor was overdue.

"We do believe that it has recurrence intervals of several thousand years," he told reporters. "We have no idea when it might rupture in the future."

New Zealand Prime Minister John Key said it was "fanciful" to suggest the country's capital should be moved because of the quake threat.

"It doesn't actually change anything - there are other big fault lines in Wellington," he told reporters.

"This just shows we're getting better at finding out where they are."

New building codes

GeoNet earthquake geologist Russ Van Dissen said the latest discovery was just one of "dozens" of active faults crisscrossing the Wellington terrain, the biggest capable of generating a magnitude-8.5 tremor.

He said the city's existing building codes should deal with any quake from the new fault.

"There's no way of saying that a magnitude seven is inconsequential, it would be damaging," he said. "But the level of shaking for this fault, we anticipate, would be less than what this city's already designed for."

Van Dissen said there were probably more undiscovered faults beneath the city.

"How does it compare internationally? You've got the North Anatolian fault going right through Istanbul. There's a number of other cities - Tokyo, San Francisco, Los Angeles, Seattle - that all have a significant active fault earthquake hazard," he said.

(China Daily 10/09/2014 page11)