A second powerful earthquake in as many days jolted Southeast Asia and triggered a regional tsunami warning Thursday, damaging hundreds of buildings along Indonesia's western coast and sending panicked residents fleeing inland.
At least nine people were killed and 49 injured in the twin tremors, which caused tall buildings to sway in at least three countries.
On Wednesday, an 8.4-magnitude earthquake triggered a small non-destructive tsunami off Indonesia's coastal city of Padang on Sumatra, the island ravaged by the 2004 tsunami disaster. A tsunami warning was issued for wide areas of the region and nations as far away as Africa.
Thursday's magnitude-7.8 quake rattled the same area of Sumatra and caused extensive damage.
"Many buildings collapsed after this morning's quake," Padang Mayor Fauzi Bahar told El Shinta radio. "We're still trying to find out about victims."
Thousands of frightened people piled in trucks or sought shelter on high ground.
Rafael Abreu, a geologist with the U.S. Geological Survey, said Thursday's quake did not appear to be an aftershock to the temblor the day before. But the centers of both were close together.
"We are not calling it an aftershock at this point. It's fairly large itself. It seems to be a different earthquake," Abreu said.
"The quake seems to be pretty shallow," he said. "These are the quakes that can produce tsunamis."
Indonesia issued a tsunami warning, lifted it and then reissued it. Australia's Bureau of Meteorology issued a warning that unusual waves could hit Christmas Island early Thursday, but locals said there was no sign of a tsunami about an hour after the predicted time.
"The danger has passed," said Linda Cash, a manager at the Christmas Island Visitors Center, adding that police were warning people to stay away from beaches. "There was no wave or damage or anything."
The USGS said the new quake was centered about 200 kilometers (125 miles) from the Sumatran city of Bengkulu. It occurred at a shallow depth of about 10 kilometers (six miles) and struck at 6:49 a.m.
The Pacific Tsunami Warning Center in Hawaii warned Thursday's quake had the potential to generate a destructive regional tsunami along coasts within 1,000 kilometers (600 miles) of the epicenter. It advised authorities to take immediate action to evacuate coastal areas.