Scientists from all over the world have been studying New Zealand's earthquake patterns and now a large science drilling ship is looking into the country's biggest fault line.
The ship is currently docked in Christchurch between expeditions to discover more about The Hikurangi Subduction Zone, which stretches from Malborough to the East Coast of the North Island.
NIWA scientist Philip Barnes said the scientists collecting what they call "logging data".
"Basically, geophysical information about the layers and the fault beneath the sea floor."
The JOIDES Resolution is a dedicated research vessel funded by the international ocean discovery programme.
Scientists have spent the past six weeks off the coast of Gisborne studying the Hikurangi Subduction Zone.
GNS Science’s Laura Wallace said the zone has the potential to produce the largest earthquakes in New Zealand.
"Most of that subduction plate boundary is beneath the ocean.
"So if there was a big earthquake on that plate boundary a large amount of sea floor could be displaced and a tsunami could be generated," Ms Wallace said.
Slow-slip events are the focus, the 2016 Kaikoura earthquake caused a slow-slip on the Hikurangi fault.
Ms Wallace said the slow-slips are similar to earthquakes because they involve more rapid than normal fault movement.
"But an earthquake takes a matter of seconds to occur whereas these slow slip events take weeks, to months, to years to occur and we really don't understand why they happen."
The fault line is of interest to scientists from all over the world, however this is the first time they have drilled into it to explore its geology.
The mission is part of a more than 40 million dollar international project to study New Zealand's most dangerous fault line.