Tsunami gauges 'stabilising'

Tsunami warning gauges are showing the initial wave has hit. Photo / GNS

Wave activity "appears to be stabilised" at previously-reported levels, Civil Defence Emergency Management says.

Waves generated by the massive earthquake in Chile at 7.35pm yesterday (NZT) were approximately one metre high at the Chatham Islands, 0.3 metres at East Cape, Napier, Castlepoint, Tauranga and North Cape, and 0.4 metres in Gisborne.

It is important to note that these are the first arrivals and larger waves may follow over the next 6 to 12 hours, Civil Defence said.

"There may also be strong surges and rapid rises in sea level in some places. The situation continues to be closely monitored."

On the Chatham Islands, residents have seen big changes in water level. Chatham Islanders took to what little high ground there is, after warnings that a major earthquake in Chile overnight had generated a tsunami.

Bernadette Malinson, of Flower Pot Bay, on Pitt Island in the Chathams, reported significant surges this morning which emptied the bay and revealed the full height of the piles on the wharf there.

"The bay empties right out. It takes about a minute and a half and then it surges back in, in about the same amount of time," she told Radio New Zealand.

"The surges have been getting bigger -- at least 2m at present."

The tidal activity, which had been going on all morning, had not caused any damage, she said.

In Akaroa, on Canterbury's Banks Peninsula, tidal surges of up to 30m were reported.

In the space of 10 minutes, the water receded almost to the swimming pontoon off the main beach in the township and then returned quickly, one witness said. Just as in Pitt Island, the pier in Akaroa was fully exposed.

The Pacific Tsunami Warning Centre (PTWC) issued a tsunami warning in response to the Chile earthquake.

A tsunami was generated, with wave measuring 2.34m was measured at Talcahuano, Chile and 0.35m at Easter Island, Chile.

Specialists said a threat to beachs and small boats existed for the east coasts of the North and South Island, as far around as Puysegur Point on the Southland west coast, and north to Cape Reinga and extending south to Ahipara, on the Far North west coast.

Sea levels along the Gisborne coast had dropped dramatically, prompting authorities to close roads to beaches and clear away sightseers.

Waikanae Beach Holiday Park manager Diane Ross said the sea suddenly receded about 9.20am.

It was almost high tide when the water pulled out to below the low tide mark.

It dropped about one-1.5 metres in a matter of moments, Ms Ross told Radio New Zealand.

The water went "very, very brown", indicating that it was being stirred up by swirling currents, she said.

All the holidaymakers at the campground had been evacuated early this morning and were watching the action from a marae at nearby Kaiti Hill.

Gisborne Civil Defence controller John Davies confirmed the witness reports, saying the sea had dropped about a metre and while it had not surged back in, there was "unusual" wave activity happening.

The wave movement was clearly building and it was essential people kept away from the coastline for the next 10-12 hours, he said.

There were still "idiots" been seen heading to the beach with surfboards on their cars, a Gisborne witness said.

In the Northland charter boat port of Tutukaka the first of the surges to hit the coast was about a metre high and turned the normally placid harbour into a 'washing machine.'

"The wave was approximately one metre. It sucks out and comes in. It takes a couple of minutes. They are very long waves," Jeroen Jongejans, who runs Dive Tutukaka, told NZPA from his boat near the harbour entrance.

Sightseers keen for a glimpse of the predicted tsunami were hitting the roads to Hawke's Bay's coast. Emergency services said the tsunami danger message did not appear to have gotten through to many people, who were heading for areas in the process of being evacuated.

The coastal settlements of Ocean Beach and Waimarama have been evacuated, and police were door-knocking at Haumoana and Te Awanga, warning residents it would be a good idea to leave.

Eleven houses right on the beach at Te Awanga were particularly at risk. One of those residents was recently prosecuted for building an illegal sea wall to stop the heavy seas eroding his backyard.

Sightseers keen for a glimpse of the predicted tsunami were hitting the roads to the coast.

In Auckland, ports of Auckland was moving ships out to sea, and warning boaties to stay out of shipping lanes.

Ken Gledhill of GNS Science said New Zealand was not in the main beam of the tsunami, which was headed for Japan.

It was still expected to hit this country, and a lack of recorders across the Pacific Ocean from Chile meant it was hard to predict how big the tsunami would be.

Four major waves had hit French Polynesia, Tahiti had a water level rise of up to two metres, with little damage, and the water was being sucked out and returning at a higher level the Chatham Islands, though the full force had yet to arrive.

Dr Gledhill said "we can say it's unlikely to be very destructive". The tsunami would be mainly a marine threat, he told TVNZ. Some pockets could be worse than others.

- NZPA