"The Hikurangi plate boundary is the fastest moving slow slip in New Zealand."
The research, which is being carried out into next year, involves scientists from Japan the United States, United Kingdom, Europe and New Zealand.
"We need to build up a bigger picture of the plate boundary, including seismic imaging of the sea floor and hopefully within a few years we will have a better understanding of what is going on in that subduction zone," Boersen said.
Studies of the effects of a major tsunami, similar to that which hit coastal Japan following a massive 9.1 earthquake on March 11, 2011, with 30-foot (9m) waves, show what we could expect if there is a rupture on the Hikurangi plate boundary, the Tararua group were told.
"We can learn from that Japanese and the 2004 Boxing Day tsunamis," Boersen said. "We are sharing science and trying to understand more. There are things we can't stop, but there are things we can do to mitigate risk."
Mr Driver said slow slips can set off faults in Tararua and cause a major earthquake, so educating civil defence staff is vital, with our coastal boundaries along the East Coast at Akitio and Herbertville.
On the banks of the Tukituki River, Alan Daly, emergency officer for the Hastings District Council, discussed civil defence scenarios, conceding "every event is different".
Mr Daly demonstrated the latest civil defence warning device, a mobile stinger, which has 10 pre-recorded messages.
"The biggest risk to life is a tsunami and for a far-source event there would be time to use the stinger to warn people," he said. However, with a local-source earthquake, the message "if it's long and strong, be gone" would mean coastal communities would have to self-evacuate.
"It's what we've been doing for 15 years now," Donna De'admin, an Akitio civil defence volunteer, said.
But it's storm surges which are the most regular event along the coast at Haumoana, Mr Daly said.
"About four times a year we have a major easterly swell, with property inundation. There used to be 21 houses along this piece of coastline, but three have been washed away. We are living in a pretty dangerous environment."
The Tararua visitors also learnt about the 2011 Waimarama floods.
"The whole area was smashed by a weather bomb," Mr Daly said. "A year's rainfall fell in 36 hours. That's Mother Nature for you."
With sea erosion taking away land at the Clifton Beach camps, Mr Daly said the road has been rebuilt four times. Akitio residents and the Tararua District Council are facing similar issues, with a stone wall built and planting undertaken to try and hold back the sea.
The final visit of a very busy day was to the Hawke's Bay emergency management centre in Hastings which covers Central Hawke's Bay, Napier, Hastings and Wairoa.
