Destructive tsunami unlikely: US Gelogical Survey

Courtesy: ZeeNews

Washington: The United States Geological Survey (USGS) has said the chances of a destructive tsunami following the massive 8.6 magnitude Indonesia earthquake were unlikely. USGS’ Bruce Presgrave told the BBC that during the earthquake, since the earth had moved horizontally rather than vertically, large volumes of water did not get displaced.

One expert told the BBC today's quake was a "strike-slip" fault, meaning a more horizontal shift of the ground under the sea as opposed to a sudden vertical shift. He said this meant there was less risk of a large displacement of water triggering a tsunami.

The quake was also felt in Sri Lanka, where office workers in the capital, Colombo, fled their offices, and the southern Thai holiday island of Phuket, both of which were hit hard by the 2004 tsunami.

In Bangladesh, where two tremors were felt, authorities said there appeared to be no threat of a tsunami. Australia also said there was no threat of a tsunami there.

Tsunami risk eases after massive Indonesian earthquake (Courtesy: TV New Zealand)

An 8.6 magnitude earthquake has struck off the coast of Indonesia, sending residents around the region dashing out of their homes and offices in fear.

The Pacific Tsunami Warning Centre said a tsunami watch was in effect for the entire Indian Ocean and individual countries, including Thailand, Indonesia, Sri Lanka and India, issued tsunami warnings.

The centre later said the threat of a big tsunami had receded, although the warning remained in place.

"It doesn't look like a major tsunami. But we are still monitoring as tsunamis come in waves," Victor Sardina, a geophysicist on duty at the Hawaii-based institute, said.

People near the coast in six Thai provinces were ordered to higher ground.

The quake struck 500 kilometres southwest of the city of Banda Aceh, on the northern tip of Indonesia's Sumatra island, at a depth of 33km, the US Geological survey said.

Indonesia's president said there were no reports of casualties or damage from the huge earthquake.

"There is no tsunami threat although we are on alert," said President Susilo Bambang Yudhoyono at a joint news conference with visiting British Prime Minister David Cameron, who said Britain was standing ready to help if needed.

"The situation in Aceh is under control, there's a little bit of panic but people can go to higher ground," Yudhoyono said, adding that he had ordered a disaster relief team to fly to Aceh.

Indonesia's disaster management agency said power was down in Aceh province and people were gathering on high ground as sirens warned of the danger.

"The electricity is down, there are traffic jams to access higher ground. Sirens and Koran recitals from mosques are everywhere," said Sutopo, spokesman for the agency.

The quake was felt as far away as the Thai capital, Bangkok, and in southern India, residents said.

Hundreds of office workers in the Indian city of Bangalore left their buildings while the Indian port of Chennai closed down because of the danger of a tsunami, the port said.

Civil Defence said there was no current tsunami watch or advisory in effect for New Zealand.

A tsunami watch means there is potential for a tsunami, not that one is on its way.

The quake was in roughly in the same area as a December 26, 2004, magnitude 9.1 quake which sent huge tsunami waves crashing into Sumatra and across the Indian Ocean.

In all, the 2004 tsunami killed about 230,000 people in 13 Indian Ocean countries, including Thailand, Sri Lanka and India.

The 2004 quake was at a depth of 30km along a fault line running under the Indian Ocean, off western Indonesia and up into the Bay of Bengal.