A man evacuates his family members on a motorcycle in Banda Aceh after a strong earthquake struck Indonesia on Wednesday. (Reuters)

April 11: Back-to-back tsunami warnings after a powerful earthquake and a series of strong aftershocks off Indonesia drove countless people out of offices and homes in countries, including India, all along the rim of the Indian Ocean today.

No deadly waves or serious damage was reported till 8pm, and a watch for much of the Indian Ocean was lifted after a few hours.

The tremors were felt in several parts of Odisha (See Metro) and they sent people scurrying from buildings as far away as southern India.

While in Bhubaneswar the seven-storey Fortune Tower developed cracks on its outer walls, in Calcutta, Metro train services were suspended for sometime as a precautionary measure — the first time such a step was taken because of a tsunami alert.

India withdrew the national tsunami alert in the evening. “Thankfully, the danger has passed,” a scientist at the Indian tsunami warning centre said. Disaster officials had earlier warned that waves as high as 3.9 metres could hit parts of Andaman and Nicobar islands. A few thousand people were evacuated from the more vulnerable islands, a police official said.

Hundreds of office workers in Bangalore left their buildings while the port of Chennai closed down because of tsunami fears.

Indonesia said it was checking for damage and casualties but remarkably, no such reports had been received for several hours after the quakes, including in Aceh, the closest province and the area decimated by the disaster eight years ago.

However, some areas close to the epicentre are remote, so it could take some time to find out if there was any damage.

Many people were frightened of further tremors.

“It’s dark out here, but I am scared to go home,” said Mila, a 41-year-old woman, taking refuge in the grand mosque in the town of Banda Aceh, the provincial capital. “I just want to stay alert, because I fear there will be more quakes coming. We are human, it is only natural that we have fear, but I really wish we will all be safe.”

Waves of up to 1-metre high were seen near islands off Aceh, but Indonesia cancelled a warning for fresh tsunamis. It said the worst hit area was the thinly populated island of Simeulue off Aceh’s southern coast.

The first quake struck at 0838 GMT and an 8.2 magnitude aftershock just over two hours later, at 1043 GMT. Two more strong aftershocks hit later.

The Hawaii-based Pacific Tsunami Warning Centre also withdrew tsunami warnings for the entire Indian Ocean after keeping them in force for several hours. “Level readings now indicate that the threat has diminished or is over for most areas,” the agency’s bulletin said.

The quakes were about 500km southwest of Banda Aceh, on the northern tip of Indonesia’s Sumatra island, the US Geological survey said. The first was at a depth of 33km. The quakes were in roughly in the same area as the 2004 quake, which 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.

Thailand, Indonesia, Sri Lanka and India were all badly hit in 2004. At least 2,30,000 people in 13 Indian Ocean countries died in the disaster a day after Christmas that year, including 1,70,000 in and around Aceh alone.

Last year, an earthquake and tsunami off Japan’s northeastern coast killed at least 23,000 people and triggered the world’s worst nuclear crisis in 25 years after waves battered a nuclear power station.

On Wednesday, people near the coast in six Thai provinces were ordered to move to higher ground. Authorities shut down the international airport in the Thai beach resort province of Phuket.

Indonesia’s disaster management agency said power failed 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 warning system worked,” Indonesian President Susilo Bambang Yudhoyono said.

Warning sirens also rang out across the Thai island of Phuket, a tourist hotspot, which was one of the worst hit areas in the 2004 tsunami.

“Guests from expensive hotels overlooking Phuket’s beaches were evacuated to the hills behind and local people were driving away in cars and on motorcycles. Everyone seemed calm, the warning had been issued well in advance,” freelance journalist Apichai Thonoy said over telephone.

Indonesian television showed people gathering in mosques in Banda Aceh. Many others were on the streets, holding crying children.