Earthquake cluster and tsunami alert: What you need to know

Friday, 5 March 2021

The tsunami alert issued following a cluster of earthquakes off the coast of New Zealand on Friday morning has now been cancelled.

GNS Science advised the largest waves have passed and the tsunami threat is now over following a magnitude 8.1 quake, the third big earthquake of the day.

Residents across the east coast of Northland evacuated to higher ground on Friday.

Evacuees have been told they can return home, however, people should still stay off beach and shore areas.

The tsunami warning followed a magnitude 8.1 earthquake, north-east of New Zealand near the Kermadec Islands, at 8.28am.

The epicentre was 100 km east of Te Araroa.

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Residents in Northland, Bay of Plenty and Great Barrier Island were told to “leave immediately for higher ground”.

Civil Defence warned those people to move out of all tsunami evacuation zones, or as far inland as possible.

The quake cluster

The first of three quakes hit at 2.27am about 100km east of Te Araroa. More than 50,000 people reported shaking on GeoNet.

As a result, the National Emergency Management Agency issued a land and marine warning of coastal inundation (flooding of land areas) on the East Coast of the North Island from Cape Runaway to Tolaga Bay. That specific threat was later lifted.

After that a 7.4 magnitude quake hit near the Kermadec Islands about 6.40am, at a depth of about 56km.

It was followed by the 8.1 earthquake, also near the Kermadec Islands, at 8.28am.

Evacuation zones

People in certain east coast areas of the North Island were told to move to high ground. These areas were: Bay of Islands to Whangārei, from Matata to Tolaga Bay, and Great Barrier Island. Civil Defence says you must move immediately.

The land and marine warning, which was extended to include some West Coast areas – from Cape Reinga to Ahipara – was downgraded to a beach and marine warning on Friday afternoon.

Beach and marine warning

A beach and marine threat remains in place for the Coromandel Peninsula and Firth of Thames. There is no existing threat for the Waikato region’s west coast, and the risk of coastal inundation has been removed.

People in or near the sea are reminded to get out of the water, off beaches and shore areas and stay away from harbours, rivers and estuaries.

Here's the advice from Civil Defence Waikato:

Move out of the water, off beaches and shore areas and away from harbours, rivers and estuaries
Do not go to the coast to watch the unusual wave activity as there may be dangerous and unpredictable surges
Listen to local civil defence authorities and follow any instructions
Share this information with family, neighbours and friends.

‘Strong and unusual currents, and unpredictable surges’

The National Emergency Management Agency said many coastal areas around the country, including parts of the South Island, could expect “strong and unusual currents and unpredictable surges near the shore”. These conditions could last for several hours.

“This means a threat to beach, harbour, estuary and small boat activities,” a statement from the agency says.

“Strong currents and surges can injure and drown people,” a Facebook post by Civil Defence Waikato read. “There is a danger to swimmers, surfers, people fishing, small boats and anyone in or near the water close to shore.

“Strong and unusual currents and unpredictable surges will continue for several hours and the threat must be regarded as real until this Advisory is cancelled.”

GNS Science said the largest waves had passed by 1.30pm.

However, People should stay out of the water, and off beaches and shore areas, the agency says.

The impacted coastal areas are:

The West Coast of the North Island from Ahipara to Makara, including the West Coast of Auckland, Manukau Harbour, New Plymouth, Whanganui and the Kapiti Coast.
The East Coast of the North Island from Whangarei to Matata including Whangarei, the East Coast of Auckland, Waiheke Island, Waitemata Harbour, and Tauranga, from Tologa Bay to Lake Ferry including Gisborne and Napier.
The West and South coasts of the South Island from Farewell Spit to Puysegu Point, including Westport, Greymouth and Hokitika.
The top of the South Island from Farewell Spit to Port Underwood, including Nelson, Picton and the Marlborough Sounds.
The East and South coasts of the South Island from the Waipara River to the Rakaia River, including Christchurch and Banks Peninsula, from the Taieri River to Puysegur Point, including Invercargill.
Stewart Island.