Skip to main content
Published: 2011-03-12 00:00:00

A marine threat remains in place for Waikato’s east coast this morning and people are being urged to stay away from the ocean and other waterways, with tidal gauges detecting the first surges in the area.

While the marine threat has been lifted for the region’s west coast beaches, coastal water users should remain alert to higher water levels and waves.

The national advisory was issued following an earthquake measuring 8.9 near the east coast of Honshu, Japan, just before 7pm NZDT yesterday (11 March). A tsunami was generated with waves at least four metres high affecting coastal Japan.

A marine threat means strong and unusual currents are possible in the sea, harbours, river mouths and estuaries, and unusual wave activity is possible at beaches. Members of the public are advised that the water can move at force and travel up estuaries and coastal rivers.

Waikato Region Civil Defence Emergency Management Group has been monitoring the threat and activated last night to provide advice to the public as necessary and respond as required.

Last night, the Thames Valley Emergency Operating Area (EOA), which covers operations on the region’s east coast, and the Waikato Valley EOA, which covers the region’s west coast, also activated.

Emergency services were advised last night of the marine threat and its possible impact so they could warn the public and monitor the developing situation.

Waikato Civil Defence group controller Chris McLay urged boaties and swimmers to remain on land while the marine threat is in place.

“As at 9am today, Environment Waikato tide gauges had registered a 30cm tidal movement. However, we have been advised that it is impossible to predict with any certainty what size the waves or tidal surges will be,” Mr McLay said.

“Waves or surges of up to one metre is possible. While it might not seem very high, that surge of water could be powerful enough to knock a person down and sweep them out.

“Following last year’s Chilean tsunami, considerable tidal impacts were observed in our east coast harbours for many days after the initial surges. People need to remain vigilant to the potential impacts on our coastal waterways beyond just today,” Mr McLay said.

On the east coast people should:

  • stay off beaches
  • stay out of the water (sea, rivers and estuaries, including boating activities)
  • not go sightseeing
  • share this information with family, neighbours and friends
  • listen to the radio and/or TV for updates
  • follow the instructions of local Civil Defence authorities.

For more information about tsunami preparedness members of the public should visit

Updated information on the marine threat is also available via the Ministry of Civil Defence and Emergency Management’s website,