By dpa news.
Indonesian authorities lifted off double tsunami warnings Thursday after two more strong aftershocks rocked the Sumatran island, adding fresh fears among thousands of residents that stayed outdoors following the initial powerful tremblor the night before.
Officials at Jakarta's Meteorology and Geophysics Agency (BMG) said another 6.7-magnitude aftershock rattled Sumatra shortly before 9 am (0200 GMT), after an earlier 7.8-magnitude quake struck at 6:49 am (2349 GMT Wednesday).
Both aftershocks triggered government authorities to issue tsunami warnings, but they were lifted after no waves materialized, officials said.
The USGS said the first new quake on Thursday was centered about 200 kilometres from Bengkulu, a city on Sumatra. It occurred at a shallow depth of about 10 kilometres.
The Pacific Tsunami Warning Centre in Hawaii warned Thursday's quake had the potential to generate a destructive regional tsunami along coasts within 600 miles of the epicentre. It advised authorities to take immediate action to evacuate coastal areas.
Thursday's quake caused extensive damage in Padang, a local official said.
"Many buildings collapsed after this morning's quake," Fauzi Bahar, the mayor, told El Shinta radio. "We're still trying to find out about victims.
On Wednesday, a powerful 8.2-magnitude earthquake shook South-East Asia, collapsing buildings, killing at least five people and injuring dozens in Indonesia. That tremor triggered a small non-destructive tsunami off the coastal city of Padang on Sumatra, the Indonesian island ravaged by the 2004 tsunami disaster.
A tsunami warning was issued for wide areas of the region and nations as far away as Sri Lanka.
Officials said at least three people were killed in Bengkulu provincial capital from Wednesday's powerful quake, while more than a dozen were injured. dpa ff sh pw
Shake map of the quake.
According to the United States Geological Survey (USGS) a second massive earthquake, magnitude 7.8 struck Indonesia at 6:49 a.m. (local time) 23:49 (UTC). The epicenter of the earthquake was located 185 kilometers (115 miles) south, southeast of Padang, Sumatra, Indonesia with a depth of 10 km (6.2 miles). Just hours ago on September 12, a massive 8.4 quake struck in the same region killing six people and injuring hundreds.

Several aftershocks have rocked the same area, the latest measuring 7.1, had a depth of 10 km. It was first reported to be a 7.3 aftershock.
Location map of quake.
The National Oceanic and Atmospheric Administration (NOAA) had issued a tsunami warning saying that the quake had the potential to "generate a destructive local tsunami and sometimes regional destructive tsunamis along coasts located usually no more than a thousand kilometers from the earthquake epicenter," but it was later lifted because no tsunamis were generated. Australia was also included in the warning. An advisory was sent out for the 6.5 aftershock stating that there was "no widespread tsunami threat based on earthquake historical data."

There is no word on injuries, deaths, or damage, but the USGS states that damage could be "moderate to heavy." The quake was felt in Singapore where buildings are reported to have shook.