National Advisory: Tsunami Potential Marine and Beach Threat
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No: 04

National Advisory – Tsunami: Potential Marine and Beach Threat remains in force for selected coastal areas of New Zealand.

The Ministry of Civil Defence & Emergency Management (MCDEM) issued a national advisory at 17:20 pm 6 February 2013 for - tsunami potential marine and beach threat for parts of New Zealand’s coast from Taranaki to Milford Sound. The New Zealand Tsunami Expert Panel has advised that the potential marine and beach threat is likely to last through the early hours of Thursday 7 February 2013. The threat is judged to be low, likely to be undetectable except in enclosed bays that traditionally have abnormal current flows. See the attached map for affected areas.

People in the above coastal areas should:

1. Stay out of the water (sea, rivers and estuaries, including boating activities)
2. Stay off beaches and shore areas
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 local civil defence authorities

The attached map shows the estimated tsunami threat-level based on the anticipated maximum tsunami amplitudes for the New Zealand coastal zones.

Historical comparisons suggest that the amplitudes are likely to be greatest in the central west coast of New Zealand, between Hokitika and New Plymouth. Elsewhere it is anticipated that the threat lies towards the lower end of the Marine Threat (0.2-1.0 m amplitude) band.

Historical experience and modelling experience suggest that the largest waves will be several hours (~2-8 hours) after the first arrivals. The first arrivals are likely to be small.

In many locations the primary concern is likely to come from strong currents within harbours and surges in river mouths.

The tsunami potential marine and beach threat will remain in effect until a cancellation message is issued by MCDEM.

Only messages issued by MCDEM represent the official warning status for New Zealand, not those issued by the Pacific Tsunami Warning Centre (PTWC).

This national advisory has been issued to all local civil defence authorities, emergency services, other agencies and media. Local civil defence authorities will interpret this information for their areas and advise public action via local radio stations.

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More Detail

Areas under ‘Marine and Beach Threat’: Expect unusually strong currents and unpredictable water flows near the shore. This means a threat to beach, harbour, estuary and small boat activities. The severity of currents and changing water flows will vary within a particular coastal area and over the period this warning is in effect. Current assessments indicate that coastal inundation (flooding of land areas near the shore) is not expected but this assessment may change.

Note:
• The wave amplitudes given indicate the largest expected wave activity at any coastal point in the particular coastal zone and at any time during the entire period this warning is in effect (tsunami activity will vary in a zone and with time; the first wave activity may also not be the largest).
• The given amplitudes do not include the local tidal or sea state at the time of tsunami activity.
• Local authorities will determine the implication of the expected wave heights for their areas and will decide on appropriate response.
This warning has been issued to all local civil defence authorities, emergency services, other agencies and media. MCDEM and scientific advisors are closely monitoring the situation to update this assessment. Information will be updated or repeated at least hourly until this warning is cancelled. Also see www.civildefence.govt.nz

We note the Pacific Tsunami Warning Centre (PTWC) has issued a Tsunami Cancellation for this event. PTWC messages do not represent the official warning status for New Zealand.
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Information for emergency managers

An earthquake has occurred with these parameters:
Origin time: 0112 ZULU 06 FEB 2013
NZ time: 1412 NZDT 06 FEB 2013
Co-ordinates: 10.9 SOUTH 165.1 EAST
Depth: 33 KM
Location: SANTA CRUZ ISLANDS
Magnitude: 8.0

Estimates of expected threat levels are as per the attached map.

Local and regional/Group Civil Defence Emergency Management must:

1. Maintain activation of appropriate response coordination arrangements and communication processes
2. Keep potentially at-risk communities informed as appropriate
3. Maintain contact with the MCDEM Regional Emergency Management Advisors (CDEM Groups only)
4. Stand by for further information.

Local CDEM to act in coordination with regional/Group CDEM.

Local emergency services must establish and maintain active response coordination with respective local and regional/Group Civil Defence Emergency Management.

MCDEM has activated the Memorandum of Understanding (MoU) with public broadcasters to broadcast this warning.
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NCMC status

The National Crisis Management Centre (NCMC) is activated.

Useful websites
http://www.civildefence.govt.nz/
http://www.getthru.govt.nz/
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Further updates

A further update with more information will follow within the next hour. Until a cancellation is issued updates will continue at least hourly. All further updates will be communicated by MCDEM via the national warning system.
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Issued by

Message authorised by the National Controller, Civil Defence Emergency Management.
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End of Message

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