SYDNEY, Jan. 22 (Xinhua) -- The Pacific Tsunami Warning Center in Hawaii had downgraded its alert for the Pacific after a 7.9-magnitude earthquake and ensuing aftershock struck Papua New Guinea (PNG) on Sunday.
The deep earthquake stuck 47 km west of Panguna on the PNG autonomous island of Bougainville at 15:30 local time (0430 GMT), the U.S. Geological Survey said, while Geoscience Australia measured a magnitude 6.2 aftershock in the same area.
The USGS initially measured the first earthquake at 8.0 magnitude and occurring in the Solomon Islands.
"Aftershocks normally continue after earthquakes this size, so we might get some more, but at this stage that's all we have," Geoscience Australia seismologist Spiro Spiliopoulos told Xinhua.
While the quake struck 150 km below the surface of the earth, the USGS predicted "strong shaking," so there is potential for some damage on the island from the quake, Spiliopoulos said.
Though no tsunami alert was issued for the Australian coastline, the Pacific Tsunami Warning Center said "hazardous tsunami waves from this earthquake are possible" throughout the Pacific and Indonesia. The alert was later downgraded to just being possible for some coasts of PNG and the Solomon Islands.
Earthquakes are common for the Pacific Islands which boarder the 4,000-km-long Pacific Australia plate to form part of the "Ring of Fire," a hotspot for seismic activity due to friction between tectonic plates.
The Solomon Islands was struck by a magnitude 7.8 and 7.0 earthquakes in early December, triggering Pacific-wide tsunami alerts while causing widespread damage on the island of Makira.