Rescue teams headed for Indonesia's Sumatra coast on Thursday (September 13) as aftershocks pounded the region where a powerful earthquake killed six people and perhaps many more the night before. Jakarta residents felt tremors from this morning's quakes. Tsunami warnings were issued but later lifted for Indian Ocean rim countries after the latest aftershocks, including a shallow quake the U.S. Geological Survey (USGS) said had a magnitude of 7.8. "We can expect aftershocks to continue for some time," USGS Geophysicist Dale Grant told Reuters. "If signs from nature keep coming, its better to stay alert and during Ramadan, we hope and pray for our safety," said Gatot. The tremors sowed fresh panic among residents in Padang, the capital of West Sumatra. The town was thrown into chaos and many fled after the initial 8.4-magnitude quake, which the USGS said was the most powerful in the world this year. In Sri Lanka. another tsunami was issued on Thursday (September 13) for people living by the seaside. The second warning came in the early hours of Thursday but it was warning for people to be on alert. Most people were unaware of the alert and there were no reports of panic. "I did not know that there was another warning. Last night, I left the beach after the warning. But this is the first time I am hearing of another one. " said a fisherman. "Another one, no I did not know until now. I will go in a little while. The tsunami want come immediately," said T. Krishnantha.