In any earthquake scenario, they should also use the “drop, cover and hold” system as a first response.
But who should have evacuated on Wednesday? Macdonald said that depended on a lot of factors.
“Everyone will feel it differently relative to where they are in relation to the epicentre, or even which type of building they are in at the time.”
He said that from his perspective in Hastings, Wednesday’s event met the “long” criteria in the area because it went over 60 seconds, but not the “strong” one as people could still stand up.
“In terms of an official evacuation, we would not start this in a long or strong scenario unless we had confirmed tsunami activity.”
GNS confirmed to the agency within 30 minutes of the quakes that there was no tsunami threat, so Macdonald said Civil Defence could then pass it on to the public.
Naturally, Macdonald said there would always be those who were underprepared, and that Civil Defence had pushed and would continue to push the “long or strong” messaging in relation to tsunami and earthquakes.
“The earthquakes that we feel are obviously close to the coastline or out at the subduction zone, so the ones we feel are ones that will have the biggest risk of a near-source tsunami.
“They could arrive at the coastline within 20-30 minutes, which is why we haven’t often got time to put out official warnings.”
Macdonald also pointed out that larger quakes could disrupt or cut off Civil Defence communications, similar to what happened in Cyclone Gabrielle.
“The ones that will cause us a big issue are around magnitude seven and eight, and we will feel those and notice damage. Warning systems rely on things like power and people being able to communicate.”
Police and other agencies also have their own systems and protocols, he said.
“They were doing reassurance patrols and giving us feedback on what was happening and who was evacuating up the hill.”
A big focus for when a larger-scale event occurred would be on immediate rapid response, providing things like food, water and shelter.
“The key thing is for people to take actions quickly to save their own lives and keep themselves safe, and once we get to the next point that’s when the wider response kicks in.”
Similar to other advice given in the Cyclone, Macdonald said there are key things people can do to prepare.
“I think the most important thing for people to remember in scenarios like this where people need to evacuate straight away is that they have a grab bag. That can just be an old, small backpack with some essential bits and pieces in it.”
People should look to the Get Ready website for more information on what to pack in their bags and other advice on preparing for natural disasters.