6.5-magnitude quake shakes southern PhilippinesA 6.5-magnitude earthquake struck off the southern Philippines on Friday, the United States Geological Survey (USGS) said, less than three weeks after a powerful tremor in the same region killed more than 80 people.The quake struck at 7:42 pm (local time) at a depth of 52.4 kilometres (33 miles), about 35 kilometres southwest of Jose Abad Santos town on Mindanao island, according to the USGS, which revised its initial magnitude estimate from 6.7 to 6.5.Rescue official Jerson Talahig of Santa Maria town said that there were no immediate reports of casualties or damage following the earthquake."It was kind of strong, but it was quick. We saw the table and some of the lights shaking," he said, as cited by AP. No subsequent tsunami alert was issued.The latest earthquake struck less than three weeks after a devastating 7.8-magnitude tremor hit Mindanao on June 8, bringing down buildings, triggering landslides and displacing thousands across the southern island. The quake also prompted tsunami warnings across the region.The powerful tremor lifted the seabed by two metres (6.6 feet) along a long stretch of coastline, exposing previously submerged coral and extending parts of the shoreline by up to 200 metres in a geological phenomenon known as "coastal uplift".A series of strong aftershocks followed, beginning about two hours after the initial quake, including a magnitude 6.5 tremor. As of Friday, the June 8 earthquake had claimed 81 lives and injured more than 1,300 people.Earthquakes are common in the Philippines, which lies along the Pacific "Ring of Fire", a seismically active belt that stretches from Japan through Southeast Asia and across the Pacific Ocean.The Cotabato Trench, located as close as 50 kilometres (31 miles) off the southern coast of Mindanao, is a frequent source of seismic activity. In January itself, the area experienced a "swarm" of thousands of mostly minor earthquakes.