Six strong aftershocks shook Indonesia in the early hours of the morning, after a massive 7.8-magnitude below-sea earthquake yesterday.
Hundreds of residents in the Sumatran island port of Padang fled to higher ground in panic after the quake, which sparked fears of a tsunami similar to the 2004 tragedy which killed more than 200,000 people.
However, authorities said there were no reports of deaths or major damage to buildings.
The National Meteorological Agency recorded half a dozen aftershocks had been felt overnight, but said they were diminishing in strength and called for calm in the face of "rumours" that another - even more powerful - quake may be on the way.
There is no information on any deaths from a major earthquake that struck off Indonesia, a search and rescue official told Reuters.
It had earlier been reported that some people have been killed but how many was unknown.
But head of operations Heronimus Guru said: "Up until now, there is no information about deaths."
The magnitude of the earthquake in Indonesia has been revised to 7.8 on the Richter scale and 15 miles deep, according to the USGS.
Deaths have been reported following the earthquake that struck off Indonesia's island of Sumatra.
It is not yet clear how many people are dead.
"There are some who have died," said Heronimus Guru, the deputy head of operations at the country's search and rescue agency told Reuters.
A tsunami warning for Sumatra that was issued following a major earthquake off the western part of the island has been lifted, a meterological agency official told Indonesian channel TVRI.
The tsunami watch for Western Australia after an earthquake struck Indonesia has been cancelled.
There are still active marine warnings for Christmas Island and Cocos Island.
A tsunami watch has been issued for parts of Western Australia, said the Australian Tsunami Warning Centre.
Indonesia has issued a tsunami warning after a powerful earthquake struck of the coast of Sumatra.
The warning is for West Sumatra, North Sumatra and Aceh after a powerful and shallow earthquake of magnitude 7.9 struck off the west coast of the Indonesian island of Sumatra on Wednesday, the National Meteorolgical Agency said.
USGS originally put the magnitude at 8.2, and then 8.1, before lowering it to 7.9.
Indonesia, especially Aceh, was badly hit by the Indian Ocean tsunami in 2004.
The country straddles the so-called "Pacific Ring of Fire", a highly seismically active zone, where different plates on the earth's crust meet and create a large number of earthquakes and volcanoes.
A powerful and shallow earthquake of magnitude 8.1 struck off the west coast of the Indonesian island of Sumatra on Wednesday, the U.S. Geological Survey said.
The epicentre was 502 miles southwest of Padang and it was six miles deep, USGS said.
There were no immediate reports of damage or casualties but the shallower a quake, the more likely it is to cause damage.
Britons in Indonesia have been warned to "maintain vigilance" after terror attacks in the capital Jakarta.
Foreign Secretary Philip Hammond condemned the "utterly senseless acts of terror".
"My thoughts are with the victims and their families," said Mr Hammond.
"We advise British nationals in Jakarta and elsewhere in Indonesia to maintain vigilance and monitor FCO travel advice, local media and to follow the advice of local security authorities."