Earth Changes
The US Geological Survey detected the epicentre near New Britain, Papua New Guinea's largest offshore island, at 4.15pm local time (7.15am BST).
It came days after another tremor measuring 6.4 hit the same region. There was no immediate information on casualties or damage.
The Pacific Tsunami Warning Centre did not release a warning following the earthquake.
"Based on all available data, there is no tsunami threat from this earthquake," a notice said.
Papua New Guinea lies on the Pacific "Ring of Fire" - a volcanically active region subject to requent earthquakes, tsunamis and volcanic eruptions.
In July 1998, two undersea quakes measuring 7.0 on the Richter scale created three tsunamis that killed at least 2,100 people near the town of Aitape.
It is not normal that they are so big. The ones forming during the summer, are usually between 20 and 30 centimeters in width, Atle Nesje, a professor at the Geological Institute of the University of Bergen, says to TV 2.
Kjetil Wiik at 330 Squadron says this hole seemed to be between 15 and 20 meters in diameter, and went very far down the ice.
Nesje thinks the hole is a melt hole formed when the melt water has been present on the surface of glacier. This is relatively common in Norwegian glaciers.
Due to the pressure it has melted itself down into glacier. When a hole appears in the glacier, it has emptied itself of the water, Nesje says, and informs that the water usually works its way through the ice until it reaches the bottom.

Floods surround houses in Vietnam’s Ha Tinh province after torrential rain submerged tens of thousands of houses.
The communist government has ordered local authorities to mobilise the army and police to rescue trapped residents following heavy downpours, state-run Vietnam television reported.
The channel said at least 11 had died in the flooding with some 27,000 homes under water in the region.
Local official Nguyen Huu Hoai said the death toll was seven in Quang Binh province, but added that conditions were improving.
University student Cooper Hallam said he was 'hit hard' from the rear left side and then took two or three bites to his body before he could react and fight off the shark.
The attack took place at Kings Beach, in Caloundra, late on Saturday afternoon.
Photographs of Mr Hallam's wounds were uploaded to the Dorsal Shark Reports Facebook page along with a description of the attack.
'Shark was obviously small, couldn't fit jaws around my waist, but still enough to give me the fright of my life,' he wrote.
'Further inspection of the bite looks like the sharks jaw size is around the diameter of a dinner plate.'
'Still very rattled... Not freaking out quite as much as my Mum though.'
Typhoon Sarika, locally known as Karen, blew into Aurora province early Sunday and was barreling fast through heavily-populated agricultural provinces with sustained winds of 130 kilometres (80 miles) per hour and gusts of 220 kph (136 mph), officials said.
Mayor Nelianto Bihasa of Baler, a popular surfing town in Aurora, said howling wind ripped tin roofs off many houses and knocked down trees and electric posts, causing power outages and blocking access roads to some villages.
Coastal villagers were warned early to move to safer areas and there have been no immediate reports of casualties other than two injured residents, he said.
In eastern Catanduanes province, a man drowned after being swept by strong river currents and a farmer died after his head hit the ground in fierce wind, provincial safety officer Gerry Beo said.
Three fishermen were reported missing, he said.
Earthquakes have historically caused widespread damage across central and southern Greece, Cyprus, Sicily and other neighboring regions.
Comment: Website Space Weather noted a geomagnetic storm on Friday 14th October 2016 (though it began early on Thursday 13th):
'GEOMAGNETIC STORM UNDERWAY: Auroras are dancing around the Arctic Circle on Oct. 14th as Earth slowly exits the magnetized wake of a CME that struck two days ago. Currently, geomagnetic storms are flickering between categories G1 and G2.
WHAT'S NEXT? On Oct. 15th, another disturbance is expected to hit Earth's magnetic field. This time it's coming from a coronal hole -- a gap in the sun's atmosphere from which solar wind flows:
NASA's Solar Dynamics Observatory took this picture on Oct. 13th. It shows the dark coronal hole pointing almost directly at Earth. At the leading edge of the emerging solar wind stream is a co-rotating interaction region (CIR)--that is, a transition zone between slow- and fast-moving solar wind. Shock waves and density gradients in CIRs often do a good job sparking auroras, so when it arrives on Oct. 15th polar auroras are likely'
More documentation of this increasing phenomenon:
- Rare 'red sprites' burst out of supercell storm in Texas
- Rare red sprites photographed over southern Arizona
- Photographs of rare red 'lightning' sprites taken in New Mexico and Europe
- Origin of mysterious jellyfish lightning 'sprites' revealed
Maui County Fire Services Chief Edward Taomoto said the woman sustained injuries to her lower leg, and was transported to Maui Memorial Medical Center in serious condition after the attack, which occurred shortly before 10 a.m.
The woman, a part-time Kihei resident, had been snorkeling in waters about 40 feet from the shore at a depth of seven feet when the attack occurred, according to a state Department of Land and Natural Resources news release.
A nearby stand-up paddleboarder heard the woman yell for help an responded to the scene. The paddler pulled the woman onto the board and brought her to shore. Also, a visitor from Washington state swam out to assist her.
Two nurses and a firefighter from the mainland who were on vacation treated the woman on the beach before lifeguards arrived, according to a Maui County Fire Department news release.
The 4-meter long Blainville's beaked whale was found on the shore near Kinmen Airport on Oct. 13.

Hand crews finish up work on the Emerald Fire along Highway 89, Friday, Oct. 14, 2016 near Lake Tahoe, Nev.
Nevada Gov. Brian Sandoval declared a state of emergency as hundreds of firefighters battled the most dangerous fire, which is still threatening hundreds of structures in the Washoe Valley along Interstate 580 and U.S. Highway 395 between Reno and Carson City.
No serious injuries have been reported but four firefighters have been treated for smoke inhalation, said Tia Rancourt, spokeswoman for the Sierra Front Interagency Fire Dispatch Center.
The wildland blaze that continued to burn out of control Friday night has charred about 3 square miles of brush and timber. It forced the closures of numerous schools and roads, and triggered widespread power outages.
Federal disaster funds were approved late Friday to help cover firefighting costs in the parched area that has only recently shown signs of recovering from a five-year drought
About 500 firefighters were on the scene Friday night at the so-called Little Valley fire, which broke out about 1:30 a.m. in the mountains between Lake Tahoe and Washoe Valley about 8 miles north of Carson City.















Comment: Another possible explanation to this mysterious hole is discussed in this article: SOTT Exclusive: The growing threat of underground fires and explosions