The Pacific Tsunami Warning Centre said there was "no tsunami threat" fromthe inland quake, which struck at 6:22 am local time (2022 GMT Saturday) at adepth of approximately 35 kilometres (21 miles).
The "notable quake" hit some 88 kilometres (54 miles) southwest of Wewak, theUSGS said, a town of 25,000 people that serves as the capital of Papua NewGuinea's East Sepik province, reports BSS.
There were no immediate reports of damage or injuries. The tremor wasdowngraded from an preliminary magnitude of 7.0.
Earthquakes are common in Papua New Guinea, which sits on top of the seismic"Ring of Fire" -- an arc of intense tectonic activity that stretches throughSoutheast Asia and across the Pacific basin.
Although they seldom cause widespread damage in the sparsely populated junglehighlands, they can trigger destructive landslides.
At least seven people were killed in April last year when a 7.0-magnitudequake hit a jungle-clad area in the country's interior.
Many of the island nation's nine million citizens live outside major townsand cities, where the difficult terrain and lack of sealed roads canseriously hamstring search-and-rescue efforts.