Sydney - A 7.4 magnitude earthquake struck off Papua New Guinea on Tuesday with tsunami waves possible along the coast, seismologists said.
The quake struck 133km south-southwest of the town of Kokopo in the New Britain region at a depth of 63km, the US Geological Survey said, and was followed by a 5.9 magnitude aftershock.
The Pacific Tsunami Warning Centre said "hazardous tsunami waves are possible for coasts located within 300km of the earthquake epicentre" before later advising that "tsunami waves reaching 0.3 to 1.0 metres above the tide level are possible".
No reported damage yet
Mathew Moihoi, a seismologist at the PNG Geophysical Observatory, said the latest quake followed a series of seismic activity in the region in recent weeks but there had been no reports of major damage to buildings or infrastructure.
"Some things fell off the shelves," he told AFP, adding that authorities were "keeping our fingers crossed" there would be no serious damage or injuries or destructive waves.
Also Read: 6.8 magnitude earthquake hits Papua New Guinea: USGS
Zenia Lopez, a worker at the Kokopo Village Resort, said she ran outside when the quake struck, but there was no damage.
"It was frightening, we all ran outside, but the place is okay, there is no damage," she said.
"We are still waiting to hear when the tsunami warning is lifted, but there are no signs of any unusual waves so far."
Tsunami waves can sometimes appear hours after an earthquake has occurred.
'We felt the earth shaking'
A receptionist at the Seaview Beach Resort in Kokopo added to AFP before the phone line cut off that "we felt the earth shaking" but that "everything was okay".
The quake hit in the remote New Britain area near Rabaul, but Moihoi said he did not think it was related to an active volcano some 110km away.
"Right now, we think it's tectonic in origin," he said. "Whether it develops a flow-on effect... we just don't know right now."
Kokopo, the capital of East New Britain, has a population of around 20 000. It started to grow after Rabaul was flattened by volcanic eruptions in 1994.
Last week, a 6.8 earthquake hit off Kokopo after a 6.7 tremor struck off the same area on Thursday. There was no reported damage.
Geoscience Australia senior seismologist Jonathan Bathgate told AFP the region had been very active recently and noted that a 7.7 magnitude earthquake occurred on March 30, generating a local tsunami. Again, there was no major damage reported.
"We don't anticipate a particularly disastrous impact," geophysicist at the Pacific Tsunami Warning Center Barry Hirshorn told Sky News of Tuesday's quake.
Also Read: Earthquake of magnitude 7.1 strikes off PNG -USGS
"We can't predict earthquakes but this area is in a very active sequence. This could be the biggest earthquake that's been building up over the last few months, but there could be another larger earthquake," Bathgate added.
"We now could endure a series of aftershocks... but it doesn't rule out the potential for a larger earthquake."
New Britain, the largest island of the Bismarck Archipelago, is east of mainland New Guinea and has a population of around 500 000 people.
It lies on the 4 000km-long Pacific Australia plate, which forms part of the "Ring of Fire", a hotspot for seismic activity due to friction between tectonic plates.
In 2013, neighbouring Solomon Islands were hit by a devastating tsunami after an 8.0-magnitude earthquake rattled the region, leaving at least 10 people dead and thousands homeless after buildings were destroyed.