Could New Zealand experience a natural disaster like Japan's Tōhoku earthquake and tsunami?

It's been 10 years since a magnitude 9 earthquake struck off the coast of Japan, causing a devastating tsunami to slam the country's eastern coast, but could it happen in New Zealand?

The most powerful earthquake in Japanese history - the Tōhoku earthquake - triggered a powerful tsunami on March 11, 2011 which reached speeds of 800 km/h and claimed the lives of thousands of people.

In the years since, researchers have used the two linked natural disasters as a basis of understanding and have been looking into whether similar events could occur around the world.

Victoria University professor John Townend, from the school of geography, environment, and earth sciences, said the subduction zone where the Tōhoku earthquake occurred has a striking similarity to a subduction zone in North Island.

"[In the northeastern Japan Subduction Zone] the Pacific plate is being thrust below part of the North American plate along the Japan Trench, at a rate of more than 8cm per year," Townend said.

"This geometry is similar to that of the Hikurangi Subduction Zone along the eastern coast of the North Island, where the Pacific is being pushed below the Australian plate at something like 4cm per year."

He said the Japan earthquake concerned scientists as it occurred on the principal fault separating the two plates when one side of the fault slipped by as much as several tens of meters - something that prior to the earthquake, had not been thought possible.

"In light of observations made during the 2011 Tōhoku-oki earthquake, in a location not thought beforehand to generate earthquakes larger than magnitude 8, it is now accepted that many if not most subduction zones can produce extremely large earthquakes. This has clear ramifications for New Zealand. 

"Collaborative research undertaken by New Zealand scientists and international colleagues in the decade since the Tōhoku-oki earthquake has revealed that the potential for magnitude 9 earthquakes in the Hikurangi Subduction Zone off the eastern coast of the North Island must be considered in hazard planning and mitigation."

However, Professor Tim Stern from the school of geography, environmental and earth Science at Victoria University said while there are "strong parallels" between the two areas, there are also other aspects to consider.

"This comparison may at first appear worrying, but there are differences between the southern North Island and the localities for magnitude 9 earthquakes. The most obvious one is the southern North Island being above sea level, while the others are all located between 10 and 200 km offshore. 

"We are currently exploring these differences and similarities in an attempt to get a sense of whether our subduction zone is capable of producing rare magnitude 9 events or merely magnitude 7-8 events on a more regular time interval. Hopefully the latter!"