Work on the Alpine Fault by Faculty of Science researchers is published in Nature

26 May 2017

Researchers from the University of Auckland’s Faculty of Science, who were part of the team involved in the South Island’s Deep Fault Drilling Project, have had their results published in prestigious international journal, Nature, this month.

Dr Jennifer Eccles, School of Environment, and PhD candidate Anton Gulley, were on site for much of the drilling activity monitoring real time earthquake activity 24 hours a day. A School of Environment summer scholar, Ashley Coutts, joined the geology team and Dr Neil Broderick, Department of Physics, applied optic fibre sensors to learn more about the unique geophysics.

The project, jointly led by Victoria University of Wellington, GNS Science and the University of Otago, was a collaboration involving more than 100 scientists from 12 countries.

It began in 2011 and has to date involved two phases of drilling (at Gaunt Creek and then in the Whataroa Valley) into the South Island Alpine Fault to understand how earthquakes occur on fault lines.

“The Alpine Fault drilling projects have required tremendous collaborative effort over the last 7-plus years,” Jennifer says. “The scale of the projects, logistics, and engineering challenges to be solved in order to meet the ambitious goals of making measurements down where earthquake processes start, have helped increase the sophistication of New Zealand’s research into our subsurface.”

Neil says working on the project was eye opening, especially in such a challenging geological environment.

“Normally I’m stuck in a lab in the basement playing with infra-red light, so this was quite a different experience for me,” he says.

At Whataroa Valley scientists drilled down to almost 900 meters and discovered water at 630 metres depth that was hot enough to boil. Victoria University’s Professor Rupert Sutherland says the geothermal conditions discovered are extreme by global standards and normally found at depths greater than three kilometres.

Although all drilling on the current site has now ceased, Neil’s work continues thanks to a 2016 Marsden Fund grant.   He is collaborating with Professor John Townend from Victoria University on an ongoing project that will take more optical measurements on the current cable to measure the temperature and strain in the borehole.

The data collected will provide a way of monitoring and recording signals produced by small, high-frequency quakes and recently-revealed deep, low-pitched earthquakes, complementing measurements made with conventional seismometers. The aim is to monitor subtle changes and search for new earthquake-related phenomena over coming years.

Additonal information: Scientists discover extreme geothermal activity in South Island