Another earthquake has struck the coastal region of Sumatra in Indonesia, three months after the disaster of 26 December. The latest earthquake is serious and measured 8.2 on the Richter scale, compared with over 9 in December.

Tsunami warnings have gone out in the countries around the Indian Ocean. 

The US Geological Survey says the latest earthquake was under the sea about 125 miles (205 km) north-west of Sibolga, Sumatra, close to where the quake of 26 December struck. USGS gave a time of 4.09pm GMT, 11.09pm local time. 

After two hours from the earthquake incident, there has been no sign of a tidal wave hitting the Indonesian coast. Observers are advising that the possibility of a tidal wave has receeded.

A spokeswoman for the US Geological Survey said not all earthquakes generate a tsunami. It would have to be over 7 in magnitude, which this one was, but in a relatively shallow part of the ocean. The latest quake was 30km (18.6 miles) below the surface.

A tsunami is likely if the earthquake involves vertical movement of sections of the earth's crust but is less likely if the thrust is horizontal or sideways sliding.

There is more immediate concern about damage to buildings on land as a result of ground shaking. Buildings have also been damaged on islands off the coast closer to the epicentre of the quake. People are reported to have been trapped in wrecked buildings on the island of Nias. 

Some damage has been reported from Medan on Sumatra island, a town of 2.5 million people and the largest population centre on Sumatra. A relief worker for TearFund who had just returned to Medan from a visit to Banda Aceh said the streets shook like being on a ship at sea and the town has been plunged into a power cut.

The Pacific Tsunami Warning Center says the earthquake may have directed waves to the south west and has alerted the island of Mauritius in the Indian Ocean to the possibility of a tsunami.

In the Maldives, the government has issued an advisory message warning people to be alert. Ibrahim Ahmed, speaking on Sky News, said everyone was being vigilant, watching TV and listening to the radio. Residents in Colombo, Sri Lanka, have been told to evacuate their homes. On the coast, a mass evacuation is under way but there a few houses left since the December disaster. Word of a possible new tsunami is reported to spread "like wild fire" along the Sri Lanka coastline, even in areas where there is no electronic media.

Sky News reported that the tremour was felt over one thousand miles away.

Don Blackman, a spokesman for the US Geological Survey, said tsunami activity would not be as widespread as in December, and the effects are likely to be localised. "Certainly evacuations should be occurring. I hope they are," he said.

In Thailand, tsunami warnings have been issued and people in coastal areas have been advised to go to higher ground.

The Japanese meteorological service said the quake was as great as 8.5 on the Richter scale.

Tirana Hassan, a worker with Save The Children in Banda Aceh, said the initial earthquake was followed by numerous after-shocks. She said local people moved away from the coast.

Earthquake Indonesia

Speaking by phone from Indonesia, marine tourism official, Faisol Hashim told eTurboNews that the earthquake was felt for at least three minutes in Banda Aceh, Meulaboh and Chalang. It hit late at night local time and warnings were announced on loudspeakers in Banda Acech, and people fled to high ground.

In Meulaboh, one of the worst hit places in the December disaster, people left their beds and made their way to high ground. Also in Chalang, where no houses have been yet been rebuilt after the previous disaster, the tremour was felt strongly and people moved to safer ground on a hill just a quarter mile out of town.

The earthquake struck just a day after scientists had completed a survey of the area from Bali north to the Andaman and Nicobar islands, and gave a warning that the stress built up by the December quake was so great that another earthquake was inevitable.

Tsunami warnings have been issued for places within 600 miles of the epicenter of the quake. The Indonesian resort of Bali is thought to be in no danger as it is shielded by the land mass from waves that may be generated.

Warnings have gone out in Thailand and in India, but there was no sign of a tsunami in the first hour after the earthquake was registered.

The latest earthquake off Sumatra occurred just a day after government ministers and officials from 56 countries were meeting in Seoul, South Korea, and heard fresh calls for an Asia-wide Tsunami warning system.

They were attending a UN-sponsored conference where Klaus Toepfer, director of the UN Environment Program said there was no doubt that an early warning system was needed. "But we also have to do it for all kinds of natural hazards" he said. Toepfer said that any warning system must use local knowledge to provide an information chain on how to make people aware and trained to react very, very clearly.
In the event, people in the areas most affected responded quickly to news of the earthquake and fled from the coast. There have been no reports of a tidal wave of the severity of a tsunami in three hours, and the danger is believed to have passed.

But on the island of Nias, off Sumatra, dozens of casualties are reported in conventional surface damage resulting from the earthquake. Buildings have been wrecked and it's feared that hundreds of people have been trapped in rubble. 

Scientists from the Indonesian geophysics agency in Jakarta have said this earthquake does not appear to have triggered a tsunami, and that its effects were localised. The tremour was strong enough to have been felt as far away as Singapore.