A strong 6.7-magnitude earthquake has struck off Papua New Guinea’s north coast city of Lae on Monday. The quake, about 150 km east of Lae, was initially recorded at a depth of about 20 km, although that figure was later revised to 87 km, the US Geological Survey (USGS) said. The Pacific Tsunami Warning Center said there was no Pacific-wide tsunami. Papua New Guinea sits on the so-called Pacific “Ring of Fire”, where continental plates collide, causing frequent seismic and volcanic activity.