A huge sinkhole which emerged in Fukuoka, Japan, was covered and repaired in less than a week – out of which health and environment checks took three days.

Before and after. Image credits: Youtube

Sinkholes are natural depressions (or holes) in the surface of the Earth’s surface, (usually) caused by karst processes. Karst processes occur when the bedrocks are soluble – in other words, in 99% of all cases, in carbonate rocks (like limestone or dolomite) or evaporitic rocks (like gypsum or anhydrite). They’re relatively common in areas such as Florida and southern UK and often occur fast, without warning, causing massive damage.

This was exactly the case in Fukuoka. According to The Guardian, the sinkhole caused power cuts and disrupted phone signals, gas and water supplies, but there were no reports of injuries. It completely trashed a five-lane road, however.

The sinkhole itself was huge: 30 by 27 meters, and 15 meters deep – a monster of nothingness in the middle of the city. But Japan demonstrated its proverbial efficiency once more, repairing it completely in six days, three of which were spent on testing only. In total, 6,200 cubic metres of sand and cement were poured into the hole, astonishingly fast even by Japanese standard. Even so, the city’s Mayor Soichiro Takashima released a statement apologising for the “great trouble.”

I hate to fall into stereotypes, but when it comes to infrastructure, few do it like the Japanese.