#eqjp Tsunami marine and minor land threat warning in effect for NZ update 12

A tsunami marine and minor land threat warning is in effect for New Zealand:
The tsunami warning will remain in effect until a cancellation message is issued by MCDEM.

The Pacific Tsunami Warning Centre (PTWC) has issued a Tsunami Warning for New Zealand in response to the above earthquake. Confirmation has been received that a tsunami was generated. Wave heights of up to 4 metres have been measured in coastal Japan. Wave heights of 0.2 m have been observed in Nauru and Honiara.

LATEST (0750hrs)

The first arrival at North Cape indicates that actual arrival times may be up to an hour later than the modelled times published below.

The first wave to arrive to New Zealand was calculated to be in the area around North Cape at approximately 0623NZDT 12 March 2011.

First arrivals have been measured by coastal gauges at the New Zealand coast. At Raoul Island Kermadecs first arrival was recorded at 0635 hours today and at North Cape at 0710 hours. Initial wave amplitudes are in the order of 15cm. It is important to note that higher wave amplitudes are expected to follow in the next few hours based on modelling.

The New Zealand Tsunami Expert Panel assessment is that there is a marine and minor land threat only for parts of the upper North Island coasts of New Zealand.

Based on real-time tsunami modelling and comparison with historical events, the interpretation is that a minor land threat (i.e. wave heights just over 1 m) now exists in Northland between Ahipara and the Karikari Peninsula as well as in the Bay of Islands and the Chatham Islands. A minor land threat means there is a small potential for impacts on beaches in these areas. A marine threat (i.e. threat to the coastal marine area and small boats) remains in place for the northern North Island from Kaipara to Ahipara and south of the Karikari Peninsula to Gisborne. Unusual tidal surges may be observed in other parts of the country.

See the attached threat level map and threat zone table for further details.

As at time of issue of this update, passage of the wave through the South Pacific has been observed, however there is no indication of wave arrival in the Kermadec islands. Wave heights observed in the Pacific islands confirm the current threat assessment for New Zealand.

Monitoring of the propagation of the tsunami across the Pacific indicates that actual arrival times may be approximately an hour later than the modelled times published below.

A tsunami is a series of waves or surges and the first wave may arrive later and may not be the largest. The largest arrivals are anticipated from about 0800 NZDT and expected to last for several (at least five) hours. Tsunami activity such as unusual currents and changes in sea-level will continue for several hours after first arrivals. Tsunami wave heights cannot be accurately predicted and can vary significantly along a coast due to local effects.

Only messages issued by MCDEM represent the official warning status for New Zealand. Local civil defence authorities may supplement these messages by applying local threat assessments.

People in coastal areas should:

1. Stay off beaches
2. Stay out of the water (sea, rivers and estuaries, including boating activities)
3. Do not go sightseeing
4. Share this information with family, neighbours and friends
5. Listen to the radio and/or TV for updates
6. Follow instructions of your local Civil Defence authorities.

MCDEM and scientific advisors are closely monitoring the situation to determine the severity of the threat to New Zealand.

This warning has been issued to all local civil defence authorities, emergency services, other agencies and media.

Tsunami Threat Level Map 2 (updated 0020 NZDT 12/03/2011) .pdf 145kb
Tsunami Threat Level Map 2 (updated 0020 NZDT 12/03/2011) .jpg 166kb

Estimated Wave Arrival Times

Location	Model Wave Arrival Time
Chatham Islands-Kaingaroa	0753NZDT 12 March 2011
Chatham Islands-Waitangi	0753NZDT 12 March 2011
North Cape	0623NZDT 12 March 2011
Whangarei	No information
Auckland (West)	0723NZDT 12 March 2011
Mt Maunganui	No information
East Cape	0723NZDT 12 March 2011
Gisborne	0729NZDT 12 March 2011
New Plymouth	0808NZDT 12 March 2011
Napier	0817NZDT 12 March 2011
Wanganui	No information
Wellington	0753NZDT 12 March 2011
Nelson	1115NZDT 12 March 2011
Marlborough Sounds	No information
Westport	0837NZDT 12 March 2011
Greymouth	No information
Lyttelton	1003NZDT 12 March 2011
Timaru	No information
Milford Sound	0747NZDT 12 March 2011
Dunedin	0929NZDT 12 March 2011
Bluff	1020NZDT 12 March 2011
Stewart Island	No information

Estimated Wave Amplitudes

Ahipara to Bay of Islands	1 - 3 m
Cape Brett to Mangawhai	0.2 - 1 m
North East Auckland Coast	0.2 - 1 m
Great Barrier Island	0.2 - 1 m
Auckland East Coast	0.2 - 1 m
Coromandel Peninsula / West Coast /Firth of Thames	0.2 - 1 m
Coromandel Peninsula / East Coast	0.2 - 1 m
Western Bay of Plenty Coast	0.2 - 1 m
Eastern Bay of Plenty Coast	0.2 - 1 m
Gisborne North Coast	0.2 - 1 m
Gisborne South Coast	0.2 - 1 m
Wairoa Coast	< 0.2 m
Napier/Hastings Coast	< 0.2 m
Central Hawke's Bay Coast	< 0.2 m
Masterton / Tararua Coast	< 0.2 m
Wairarapa South Coast	< 0.2 m
Wellington South Coast	< 0.2 m
Wellington West / Kapiti Coast	< 0.2 m
Horowhenua / Manawatu / Rangitikei Coast	< 0.2 m
South Taranaki / Wanganui Coast	< 0.2 m
New Plymouth Coast	< 0.2 m
Waikato West Coast South	< 0.2 m
Waikato West Coast North	< 0.2 m
Auckland Region West Coast	< 0.2 m
Pouto Point to Reef Point	0.2 - 1 m
Marlborough East Coast	< 0.2 m
Kakioura Coast	< 0.2 m
Hurunui Coast	< 0.2 m
Christchurch North Coast	< 0.2 m
Banks Penisula	< 0.2 m
Mid to South Canterbury Coast	< 0.2 m
Waitaki Coast	< 0.2 m
Dunedin Coast	< 0.2 m
Clutha Coast	< 0.2 m
Southland Coast	< 0.2 m
Stewart Island	< 0.2 m
Fiordland Coast	< 0.2 m
Westland Coast	< 0.2 m
Greymouth Coast	< 0.2 m
Westport Coast	< 0.2 m
Kahurangi Coast	< 0.2 m
Marlborough Sounds / Tasman Bay	< 0.2 m
Chatham Islands	1 - 3 m