Tsunami Alert Eases, Danger Still Exists

The tsunami threat for New Zealand and most Pacific Ocean states is easing. First waves have now reached much of the Pacific and sea level gauges are reporting sea level changes which have been analysed.  However dangerous sea currents will exist for some hours.

Sunday 28th February 2010

Tsunami warnings are still in place for all coastal areas of New Zealand and disturbances are expected to continue for many hours.

The Pacific Tsunami Warning Centre still lists the threat as severe, but has cancelled its tsunami warning for most Pacific Ocean states, including New Zealand. New Zealand’s Ministry of Civil Defence and Emergency Management has a threat to New Zealand still in place.

Sea level gauges have now reported the arrival of the tsunami across much of the Pacific Ocean, with waves still to reach Japan and Russia. Maximum levels were reported off the coast of Chile – 2.3 metres at Talcahuano Chile at 7:53 p.m. last night New Zealand time. 1.3 metres was recorded at Valparaiso at 8:08 p.m. and 1.3 metres at Coquimbo at 9:52 p.m. In the Marquesas Islands a reading of 1.79 metres was reported at 6:41 this morning.

Easter Island reported 0.35 metres at 1:05 this morning, Rarotonga in the Cook Islands 0.32 metres at 8:18 a.m., and Tonga 0.10 metres at 9:24 a.m. Measurements in the Hawaiian Islands included measurements of 0.52 metres at Hawaii and 0.98 metres at Maui. The warning for Hawaii was cancelled at 38 minutes after midday today.

MCDEM have released readings for New Zealand sites. Waves arrived at Chatham Island at 7:35 a.m., Gisborne at 8:29, Napier at 8:53, Wellington at 8:55, Christchurch at 9:35 a.m. Readings from western coasts include arrival times of 9:35 a.m. at Milford Sound, 10:20 at Greymouth and Wanganui, 10:38 at Westport, and 11:26 at New Plymouth. Wave heights at Chatham Island were 1 metre, 0.3 metres at East Cape, Napier, Castlepoint, Tauranga and North Cape, and 0.4 metres at Gisborne.

In an update released at 12:45 today, MCDEM maintained its national warning of a tsunami threat for New Zealand. It noted, “The interpretation of the Tsunami Experts Panel is that a marine threat (i.e. threat to beach and small boats corresponding to wave heights less than 1 metre) still exists for the entire east coast of the North and South Island from Puysegur around to Cape Reinga and extending south to Ahipara. Some land threat still exists for the Chatham Islands and Banks Peninsula i.e. wave heights between 1 and 3 metres. There may be some small observable sea level changes on parts of the west coast of both islands.

Wave heights refer to maximum water level relative to the normal sea level at the beach. This does not take tides into account. Based on historical events it is expected that the greatest wave heights could occur between 6 and 12 hours after the initial arrivals.”

[Compiled from data provided by the Ministry of Civil Defence and Emergency Management and the U.S. National Oceanic & Atmospheric Administration’s Pacific Tsunami Warning Centre.]

Leave a Reply