Extreme hydrothermal conditions at an active plate-bounding fault, Rupert Sutherland et al. Nature (2017) doi:10.1038/nature22355
Researchers have found some of the most extreme underground conditions anywhere on Earth beneath the Southern Alps, including temperatures similar to that of an active volcanic zone.
The surprise discovery could have economic implications for the area, and may give clues as to the conditions of a major fault prior to a significant rupture.
An international research team has discovered "extreme" geothermal conditions deep beneath the mountains, according to research published in the Nature journal on Thursday.
Temperatures measured near the surface were similar to those found in active volcanic zones such as Taupo – yet there are no volcanoes in Westland.
The research team – led by GNS Science, Victoria University of Wellington and the University of Otago, comprising more than 100 people from 12 countries – drilled a borehole nearly 900 metres deep at a site near Whataroa in Westland.
At 630m deep, they measured water temperatures of 100 degrees Celsius, hot enough to boil. They expected temperatures of less than 40C.
Drilling further, they determined the borehole's geothermal gradient – how quickly temperature rises as you go deep into the earth – was unlike any known active fault in the world.