Japan is famous for Mt.Fuji, ninjas, sacred suicide, sushi and many more. Japan is one of the busiest countries in the world, contributing so much in the technology that we’re indulging today. Recently, the country had been the talk of the town again. Last Monday, at around 5:00 local time, a sinkhole appeared in the busy streets of Hakata district in Fukuoka city. The city is occupied by more than 1.5 million residents and is about 620 miles southwest of Tokyo.
Luckily, there were no reported casualties. The caved-in is believed to be about 100 feet wide and 25-30 feet deep, the size half of that an Olympic swimming pool. The sinkhole swallowed about five lanes in the road of the district. Investigations are still ongoing but initially, the hole is probably linked to an ongoing subway construction nearby.
There are several causes of why a sinkhole can occur. The dissolution of rocks from acid in rain water can create one. Heavy rains and surface flooding can also create sinkholes. Leaking drainage pipes, irrigation or even by simply emptying a swimming pool could set off a collapse in the land’s surface. Road constructions and other industrial developments are also potential triggering causes if the ground is supported inadequately.
There are also different types of sinkholes or also called dolines. Some sinkholes are created from soluble rocks and are washed away by acid rainwater. There are also those loose superficial materials in the surface like sand or clay that are washed, leading to a cavity within the overlying materials in the surface. In other cases, a gradual collapse of a cave can trigger a sinkhole. Other sinkholes are not cause by the dissolution of limestone but because of the constant flow of water which causes erosion. Loose material can be removed by soil piping, however creating voids within the sediments.
Fokuoka Mayor Soichiro Takashima said that an accident like that is unheard of and one should not have happened. He added that they must prevent secondary accidents and will do their utmost to restore important infrastructure. Video footages showed water bursts ejecting muddy discharge in the hole. 2000 trucks of soil and sand is needed to fill in the hole. The government is now initiating the process of filling in the void.
Way back 2014, a smaller sinkhole had already been reported at another location of the subway construction in Fokuoka.