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There have been no reports of damage to coastal areas after Tuesday's 6.8 magnitude earthquake in the South Island, GNS Science says.
But a small tsunami did take place.
"What we did see was on our tsunami gauge at Puysegur Point...we did have a 10cm tsunami observed for about 90 minutes," GNS Seismic duty officer Sam Taylor-Offord told Morning Report.
Thousands reported feeling the earthquake.
The models showed a tsunami of 30cm or larger was possible but the modelling often leans more conservatively, Taylor-Offord said.
There was a very sparse instrument network in the area, he said.
"So, in terms of coastal gauges and deep ocean gauges, we're waiting 30 or 60 minutes in some cases to see a tsunami arriving and then when we can see that something is not coming... that tells us quite a lot."
He said the network was designed around the hazard rather than where people are.
Victoria University senior research fellow Finn Illsley-Kemp said the part of the country where the earthquake took place was known as the Puysegur subduction zone, where the Australian plate was being forced underneath the Pacific plate.
He said it was a poorly understood part of the country, largely due to how remote it is.
"It's very hard to do research down there, and so we have relatively limited understanding of the tectonic processes that are happening there," Illsley-Kemp said.
He said the lack of research in the area was partly due to resourcing, but also a question of priorities.
"That part of the country, as everyone knows, is quite sparsely populated especially compared to the North Island, so a lot of our research effort has gone into the Hikurangi, but this earthquake is an important reminder that we do need to understand the tectonics in the Puysegur subduction zone as well."
NIWA oceans strategy manager Dr Joshu Mountjoy was part of a research team looking at the risk of undersea landslides and their potential to cause tsunamis along New Zealand's East Coast.
Scientists aboard the German research vessel RV Sonne were surveying and mapping areas off the Wairarapa and Canterbury coasts which had previously experienced huge landslides.
"Some of these landslides look like they're probably over 10,000 years old back when the last ice age was happening and things were really different," Mountjoy said.
"But some of them look really recent and so we're seeing landslides that have very little sediment sitting over the top of them, they are really impacting the way the submarine canyons are forming, and so those are the ones we're going to focus on for what is the process that could be happening now and could happen into the future.
"The work we're undertaking is all about understanding how a tsunami could come from submarine landslides... there's many instances of large submarine landslides around the world, and some of these have generated waves that can be tens of metres high."
Illsley-Kemp said his colleagues from Victoria University were leading a research project to put seismometers on some islands in the area to better understand the tectonics, Illsley-Kemp said.
He said there were other area similarly under-researched, especially when compared to the North Island.
"We have some understanding, and we can look at also the ocean floor, so some work from places like NIWA have mapped the sea floor and that gives us an understanding, but from an earthquake point of view there's lots of holes in our knowledge, and more research could be done in that area to better understand both the earthquake and the tsunami hazard that it might pose."
