Strong aftershocks continued to rock Indonesia on Thursday after a massive undersea quake sparked fears of a region-wide disaster similar to the 2004 Indian Ocean quake and tsunami which killed more than 200,000 people. An aftershock of 5.6 magnitude, and at a shallow depth of 10 kms (six miles), struck on Thursday morning about 784 kms (487 miles) south-southwest of the Sumataran island port of Padang, the same area as Wednesday night's 7.8 magnitude quake, said the U.S. Geological Survey (USGS). There were no reports of deaths or damage to buildings from the overnight undersea quake, which caused panic in Padang as people tried to reach higher ground when a tsunami warning was issued. No tsunami occurred. With a series of aftershocks through the night and Thursday morning, Indonesian authorities called for calm. The National Meteorological Agency said there were six aftershocks of decreasing strength during the night. "We do not believe that there will be an earthquake of greater