A 6.4-magnitude earthquake struck Papua New Guinea Thursday, the US Geological Survey reported, but no tsunami warning was immediately issued and there were no early reports of damage. The quake hit the New Britain region at 7:13 am (2113 GMT Wednesday) at a depth of 48 kilometres (30 miles), 204 kilometres southwest of the main city in the area Rabaul and 598 kilometres from national capital Port Moresby.