JAKARTA (AFP) - A 5.6-magnitude earthquake struck off the Indonesian island of Sumatra on Sunday, geologists said, although there were no immediate reports of damage or tsunami notices issued. The undersea quake hit at a depth of 39 kilometres (24 miles) at 6:52 pm (11:52 GMT) around 115 kilometres west of Bengkulu in Sumatra, the US Geological Survey said, revising down an initial 5.9-magnitude estimate. There were no tsunami warnings or advisories in effect on the website of the Hawaii-based Pacific Tsunami Warning Center.