One of the strongest earthquakes that hit the South Pacific in modern history triggered tsunami warnings in the ocean and forced thousands of people in New Zealand to evacuate coastal areas on Friday. Small tsunami waves were seen, but little damage was apparent hours later.
The 8.1 magnitude earthquake in the Kermadec Islands region, about 620 miles from New Zealand, was the largest in a series of tremors for several hours, including two previous earthquakes that recorded magnitude 7.4 and magnitude 7.3.
The tsunami threat caused traffic jams and some chaos in New Zealand as people struggled to reach higher ground.
Residents recorded videos of small waves 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 continue to avoid the beaches.
George Novak / AP
One of the first earthquakes hit much closer to New Zealand and woke up many people who felt a long, loud tremor. “I hope everyone is doing well,” wrote New Zealand Prime Minister Jacinda Ardern on Facebook overnight.
After the biggest earthquake, New Zealand’s civil defense authorities told people in some coastal areas to immediately go to higher ground. They said a damaging tsunami is possible and the waves can reach up to 3 meters.
Emergency Management Minister Kiri Allan told reporters that people followed the warning.
“They felt the earthquakes were long or strong and were able to pick up their bags and head for the mountains,” she said. “I can only thank and acknowledge the tireless efforts of men and women from all over the coast who knew how to act, when to act and what to do.”
The Pacific Tsunami Warning Center warned that the earthquake could cause tsunami waves of up to 10 feet in Vanuatu and up to 3 feet in Fiji, French Polynesia and in distant places like Mexico and Peru.
1-foot waves were measured by ocean meters in Vanuatu, New Zealand and the islands of Australia.
The US Geological Survey said the strongest earthquake occurred near the remote Kermadec islands, at a depth of 12 miles.
The agency said in a report that the earthquake occurred at the intersection of the Pacific and Australian tectonic plates and eclipsed the largest previously recorded earthquake in the region, a magnitude of 8.0 in 1976. He said the interaction between the plates creates one of the most seismically active regions in the world, and recorded 215 earthquakes above magnitude 6.0 in the past century.
Jennifer Eccles, an earthquake expert at the University of Auckland, said the earthquake was at the top of the scale for those involving only Earth’s oceanic crust.
“This is as big as it can be,” she said.
She said that most earthquakes larger than magnitude 8.0 tend to occur when a section of the more robust continental crust is involved.
The US Geological Survey said the 7.4 magnitude earthquake was probably a “prior quake” that contributed to the larger earthquake, but that the first earthquake that hit New Zealand was too far in time and distance to have contributed directly.
The first earthquake was centered at a depth of 13 miles under the ocean, about 108 miles northeast of the city of Gisborne. It was widely felt in New Zealand, and residents in major cities in Auckland, Wellington and Christchurch reported that they woke up shaken.
In 2011, a magnitude 6.3 earthquake struck the city of Christchurch, killing 185 people and destroying much of the city center.