Scientists plan to drill deep into Alpine Fault

Top international scientists are eyeing up a scrubby West Coast stream bed to carry out multimillion-dollar research into New Zealand's major "earthquake machine".

The literally ground-breaking work, which could run over several summers, will involve drilling into the South Island's Alpine Fault to understand how large faults evolve and generate earthquakes.

The Deep Fault Drilling Project has applied for resource consent to drill two boreholes about 150 metres deep and 50m apart in Gaunt Creek, near Whataroa, next year.

The location atop the Alpine Fault is said by scientists to be one of only a few such sites in the world.

GNS Science said the project would be one of New Zealand's largest field-based experiments and was an example of "big science".

It will involve 100 or more scientists and require funding from New Zealand, Germany, Britain, the United States, Canada and Australia.

"Scientists have dreamed about doing this for decades," GNS spokesman John Callan said.

"The Alpine Fault is late in its earthquake cycle, so it is seen as a great opportunity to investigate one of the top faults in New Zealand by putting a range of probes down into the zone where earthquakes occur.

"It has been their goal, almost a holy grail of earth sciences."

Project co-leader Dr John Townend, of Victoria University, said the investigation would take place in "an amazing natural laboratory".

The Alpine Fault extends more than 650 kilometres from Marlborough, along the western edge of the Southern Alps to Milford Sound.

Research suggests it ruptures every 200 to 400 years, producing damaging magnitude eight or more earthquakes.

The two boreholes will enable scientists to examine unweathered rocks, install earthquake recorders and weather gauges, and measure temperature and water pressure.

Samples will be analysed using photographs of the interior of each borehole and an X-ray scanner to examine each rock's mineralogy and structure.

Surface surveys will also be conducted using seismic imaging equipment and geological and geochemical mapping.

"The Alpine Fault offers great opportunities to investigate pressure, temperature and chemical conditions in the heart of the `earthquake machine'," Townend said.

"The Alpine Fault's geometry, rapid rate of slip, and well-studied surface exposures make it a site of real global importance for fundamental research into the evolution of large faults and the conditions under which earthquakes occur.

"Funding applications ... have been submitted in Germany, the UK, US, Canada, and Australia, as well as New Zealand, and we await the outcomes of these and future applications."

Researchers at GNS Science, Otago University and Victoria University are co-ordinating the work in collaboration with colleagues at Canterbury University and Auckland University, and organisations in Germany, Britain and the United States.

- © Fairfax NZ News