SYDNEY — A strong earthquake with a magnitude of 7.3 was recorded off Papua New Guinea's Bougainville Island, the U.S. Geological Survey said on Friday.The Pacific Tsunami Warning Centre said a destructive widespread tsunami was not expected but said waves could be generated along coasts in the area from an earthquake of that magnitude.The quake was initially measured at 7.4 but was later revised down to 7.3. It was centred in the sea about 75 km (45 miles) southwest of the main town of Arawa on Bougainville, at a depth of about 50 km (30 miles), the USGS said.