An earthquake measuring 6.3 magnitude on the Richter scale hit off Papua New Guinea, the US Geological Survey (USGS) said on Saturday. The quake was centered 120 kilometers south of Bougainville Island, according to the USGS. There were no immediate reports of casualties or damage. There was also no tsunami warning from the quake. Another quake occurred shortly after about 101 kilometers southwest of Chirovanga, Solomon Islands. The 4.8-magnitude earthquake hit at a depth of about 51 kilometers.