Like something out of a sci-fi monster movie, a gaping sinkhole has swallowed up a street in Japan.

The hole opened today, just after 5am local time, in the city center of Fukuoka on the southern island of Kyushu, Japan. Remarkably, no one was injured, although it's understandably caused disruption to the city's gas, water, and electricity utilities.

City authorities say the sinkhole is around 30 meters (98 feet) in length, 27 meters (88 feet) in width, and about 15 meters (49 feet) deep, according to Japanese newspaper The Mainichi.

"The power was out all of a sudden and I heard a loud boom. I went outside and saw a huge hole," a witness told The Mainichi.

So how did it happen? The city officials say they suspect it’s to do with ongoing construction on a subway line, which has caused smaller sinkholes before. This is a fairly typical case for sinkholes, although they can occur completely naturally.

Often they are caused by natural processes of erosion of slightly soluble bedrock by moving water trickling through a cavity roof. Eventually, the ground above the cave can't support itself and it collapses.

Images of the monster Fukuoka sinkhole, and even a video of it forming, have been spread throughout social media by bewildered locals.