The U.S. Pacific Tsunami Warning Center canceled its tsunami watch for the Indian Ocean on Wednesday hours after a massive 8.6-magnitude earthquake and several aftershocks struck off Aceh, Indonesia.
"Level readings now indicate that the threat has diminished or is over for most areas," the agency's bulletin said.
The Indian tsunami warning centre also lifted its national tsunami alert. "Thankfully, the danger has passed." a scientist at the centre told Reuters. The Phuket Internaitonal Airport also resumed operations after briefly halting flights during the tsunami threat.
The quake struck 308 miles (500 km) southwest of the city of Banda Aceh, on the northern tip of Indonesia's Sumatra island, at a depth of 20.5 miles (33 km), the U.S. Geological survey said.
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.
The quake was roughly in the same area as a Dec. 26, 2004, quake of 9.1 magnitude, which sent huge tsunami waves crashing into Sumatra, where 170,000 people were killed, 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 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.
Reuters