One of the strongest earthquakes to hit the South Pacific in modern history triggered tsunami warnings over the ocean and forced thousands of New Zealanders to evacuate the coast on Friday. Small tsunami waves were seen, but a few hours later there was obvious damage.
The magnitude 8.1 earthquake in the Kermadec Islands region, about 620 miles from New Zealand, was the largest in a series of tremors lasting several hours, including two previous earthquakes of magnitude 7.4 and magnitude 7, 3.
The tsunami threat caused traffic jams and some chaos in New Zealand as people rushed to higher ground.
Residents have recorded low-wave videos in some places, including Tokomaru Bay near Gisborne. In the afternoon, the National Emergency Management Agency said the threat had passed and people could return to their homes, although they should still avoid the beaches.
George Novak / AP
One of the previous earthquakes hit much closer to New Zealand and woke many people, feeling a long and noisy tremor. “I hope everyone is fine there,” New Zealand Prime Minister Jacinda Ardern wrote on Facebook overnight.
After the biggest quake, New Zealand’s civil defense authorities told people in some coastal areas to reach higher ground immediately. They said a harmful tsunami was possible and the waves could reach up to 10 feet.
Emergency Management Minister Kiri Allan told reporters that people followed the recommendations.
“They felt long or strong earthquakes and knew how to grab their bag and head for the mountains,” she said. “I can only thank and acknowledge the tireless efforts of the men and women up and down the coast who knew how to act, when to act and what to do.”
The Pacific Tsunami Warning Center has warned that the quake could cause tsunami waves of up to 10 feet in Vanuatu and up to 3 feet in Fiji, French Polynesia and as far as Mexico and Peru.
The 1-foot waves were measured with ocean indicators in Vanuatu, New Zealand and the islands off Australia.
The US geological study said the strongest quake was centered near the remote Kermadec Islands at a depth of 12 miles.
The agency said in a report that the quake occurred at the intersection of tectonic plates in the Pacific and Australia and eclipsed the largest earthquake ever recorded in the region, with a magnitude of 8.0 in 1976. It said the interaction between the plates creates one of the most seismic active regions in the world and recorded 215 earthquakes there over the magnitude of 6.0 in the last century.
Jennifer Eccles, an earthquake expert at the University of Auckland, said the quake was at the top of the scale for those involving only the Earth’s oceanic crust.
“That’s about as big,” she said.
She said most earthquakes larger than magnitude 8.0 tend to occur when a more robust continental crust section is involved.
The US geological study said that the magnitude 7.4 earthquake is probably a “shock” that contributed to the larger earthquake, but that the first earthquake that struck closer to New Zealand was too far in time and distance to be contributed directly.
The first earthquake was centered at a depth of 13 miles under the ocean, about 108 miles northeast of Gisborne. It was widely felt in New Zealand, and residents of the major cities of Auckland, Wellington and Christchurch reported being shaken.
In 2011, a magnitude 6.3 earthquake struck the city of Christchurch, killing 185 people and destroying much of its center.