NEW ZEALAND (CNN) — A powerful 7.8-magnitude earthquake has jolted New Zealand’s South Island and triggered a tsunami, sending people running into the streets in a panic.
The quake struck around 30 miles northeast of the city of Christchurch just after midnight local time on Monday, the US Geological Survey reported, and triggered waves of 2.49 meters above usual tide levels, the Pacific Tsunami Warning Center (PTWC) said.
“This is highest tsunami wave (that) New Zealand has seen in at least 38 years,” said Philip Duncan of Weather Watch New Zealand.
There were no immediate reports of casualties.
But New Zealand’s Ministry of Civil Defense warned that the worst may be yet to come. The agency said on Twitter that the country’s entire east coast was at threat and could expect waves of between three and five meters.
“Move inland or to higher ground immediately,” the warning said.
Initial waves may not be the largest and they could continue for several hours, the Civil Defense posted, as tsunami-warning sirens wailed across the island.
“The first tsunami waves have arrived but it is too early to know what damage or casualties there may have been.
Further waves should be expected and may be larger or more dangerous,” the Civil Defense Ministry said in a statement. “New Zealanders should stay off the beaches, stay out of the water, and not go sightseeing.”
New Zealand is a South Pacific nation of islands, the two largest being the North and South islands, which are home to most of the population.
Slightly more than 1 million people live in the South, while the North has more than 3 million.
New Zealand is regularly hit by earthquakes as it sits in a “collision zone” between the Indo-Australian and Pacific tectonic plates.
It is part of the Pacific’s “Ring of Fire,” a horseshoe-shaped belt around the ocean’s edges where many earthquakes and volcano eruptions occur.
In Christchurch, memories of a devastating 6.3-magnitude earthquake in 2011 are still fresh for many.
That quake killed 185 people and injured thousands, and reduced swathes of the city’s historic area to rubble.