|PORT MORESBY, Sept 9 (Reuters) - A powerful 7.6 magnitude earthquake struck northern Papua New Guinea on Monday, knocking coastal homes off their stilts, generating a small tsunami and killing three people, according to initial reports.
The quake hit near an area of the poor South Pacific nation where one of a similar size triggered tsunamis that killed more than 2,000 people in 1998. This time, a one to two metre (3.3-6.7 ft) wave swept ashore but caused no damage, officials said.
The Pacific Tsunami Warning Center in Hawaii issued a tsunami watch and warning for all coastal areas and islands in the Pacific, from Japan to Fiji, but the alert was soon cancelled.
The U.S. Geological Survey said the epicentre of Monday's earthquake was 60 miles (96 km) north-northwest of the coastal town of Wewak, and it struck at 4:44 a.m. (1844 GMT Sunday).
The Papua New Guinea earthquake observatory in the capital Port Moresby measured its magnitude at 7.6 on the open-ended Richter scale, said vulcanologist Chris McKee.
"Our information is that there was a tsunami but it was rather small, of the order of one to two metres in Wewak town and it was also recorded at Karkar island, which is about 350 km (220 miles) to the east of the epicentral area," McKee said. But it wasn't a damaging tsunami."
Papua New Guinea's 5.1 million people, most of whom live subsistence lifestyles, reside on the Pacific volcanic belt known as the "Ring of Fire" and large magnitude earthquakes are common.
The epicentre of Monday's quake was 33 km (20 miles) underground but at that magnitude, it was still powerful enough to have caused extensive damage in populated or built-up areas.
National Disaster and Emergency Services assistant director Martin Mose said the provincial governor had reported three deaths.
"There's been a report saying there are three dead," Mose told Reuters by telephone. "We need to properly confirm that with the hospital authorities and administration on the ground."
The quake was close to the coastal town of Aitape where more than 2,000 people were killed in July 1998 when 15-metre (50 ft) waves swept 500 metres (550 yards) inshore.
The Aitape quake measured 7.1, too small to have caused the tsunamis. Some experts say the quake may have triggered a submarine landslide that sent the huge waves roaring inland.
Monday's 7.6 earthquake had the potential on its own to generate a tsunami but the surge that resulted appeared minor.
Residents said fragile homes made of "bush material" suffered the most damage from the temblor, and coastal homes were knocked off their stilts by the shaking.
"It was serious, but it seems like minor damage and injuries. The permanent buildings have not collapsed, there are some cracks. It's mainly the village timber houses which have fallen over," said one resident of Wewak.
Several homes collapsed on the island of Wallis lying just offshore from Wewak, and Wallis and two other coral atolls, Tarawai and Kairiru, were hit by small tidal surges.
"The atolls are only about one metre above sea level so it would have rushed into the beachside villages," said a Wewak shipping company official.
Evangelical Brotherhood Church missionary Simon Bear said many villagers around Wewak panicked when the earthquake hit fearing it would produce a tsunami like those of 1998.
"I went out on the road and people were screaming a tidal wave was coming but it was just panic," Bear told Reuters.