Update 6 - Tsunami: Marine & Minor Land Threat to NZ

Summary from the latest update

Summary: The Pacific Tsunami Warning Centre (PTWC) has issued a Tsunami Warning for New Zealand in response to the above earthquake. The New Zealand Tsunami Expert Panel assessment is that there is a marine threat for New Zealand. A marine threat means strong and unusual currents are possible in the sea, river mouths and estuaries, and unusual wave activity is possible at the beach.

Confirmation has been received that a tsunami was generated. Wave heights of up to 4 metres have been measured in coastal Japan.

Based on real-time tsunami modelling and comparison with historical events, the interpretation is that a minor land threat (i.e. 1-3m wave heights) now exists in Northland between Ahipara and the Karikari Peninsula as well as in the Bay of Islands and the Chatham Islands.

A marine threat (i.e. threat to beach and small boats) remains in place for the northern North Island from Kaipara to Ahipara and south of the Karikari Peninsula to Gisborne.

The first wave to arrive to New Zealand will be in the area around North Cape at approximately 0623NZDT 12 March 2011. The first wave may arrive later and may not be the largest.

The largest arrivals are anticipated from 0800 NZDT and to last for several (at least five) hours.

Wave height refers to maximum water level relevant to the normal sea level at the beach. Tsunami activity such as unusual currents and changes in sea-level will continue for several hours.

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..