A new simulation shows what it was like to have been involved in New Zealand's only deadly tsunami, 150 years after it occured.
The Arica earthquake, estimated to have been between a magnitude 8.5 and 9.0 quake, ruptured 600km of seafloor when it struck off the coast of Peru on August 14, 1868.
It killed around 25,000 people in Chile and Peru, and then took a further 15 hours to travel across the Pacific and hit the Chatham Islands.
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The video shows the tsunami travelling across the Pacific and the tidal impacts it has once it hits land at New Zealand.
At 1am on August 15, people in the Tupuangi village on the northwest coast of the Chatham Islands woke to a loud roar as a massive wave surged inland. Three families were washed away while survivors scrambled to higher ground.
Lyttelton, Banks Peninsula, Lyttelton, Oamaru, Timaru and Port Chalmers in Dunedin also bore the brunt of the impact in New Zealand.
Three waves within one hour hit the shore - the last being the largest and most violent.
The official death toll is unclear, but it is believed that 20 people died in what has been described as the largest tsunami to ever hit New Zealand.
The tsunami was also recorded in Samoa, Hawaii, Japan, Australia, California and Oregon in the United States.
GNS scientists are heading to the Chatham Islands for the 150th anniversary of the event, joining locals for a commemoration ceremony.
"The purpose of the memorial event is to raise public awareness and promote educational opportunities about the major natural hazards - earthquakes, tsunami, volcanism, landslides, and extreme weather - and how society can become more resilient and co-exist with them," GNS scientist Hamish Campbell says.
The golden rule is if people feel earthquake shaking that lasts for a minute or longer, or if they feel strong shaking that makes it hard to stand up, they should evacuate immediately inland or to higher ground, Mr Campbell says.