Motorcyclist dies after being swallowed by sinkhole in latest such incident

The cause of the sinkhole remains unknown. Seoul officials said they planned to conduct a “detailed and comprehensive investigation.”

“We will identify the cause of the accident as quickly as possible to ensure that such incidents are not repeated and that citizens can use the roads confidently,” Seoul Mayor Oh Se-hoon told reporters at the scene on Monday.

Seoul officials said a total of 223 sinkholes appeared in the city from 2015 to 2024.

Sinkholes appear when the ground below the land surface can no longer support it, according to the U.S. Geological Survey. They frequently occur where rocks below the land surface are naturally dissolved by groundwater circulating through them.

Sinkholes can also be human-induced, with some correlated to land-use practices such as groundwater pumping and construction, the U.S. agency said.

The incident in Seoul follows a similar one earlier this year in the Japanese city of Yashio, when a truck and its driver were swallowed by a sinkhole the size of a large swimming pool. The 74-year-old driver was never found after a two-week search.

Officials said the hole was most likely caused by a damaged sewage pipe.

There is no database for sinkholes in the U.S., but according to the U.S. Geological Survey the states with the most reported damage from sinkholes are Florida, Texas, Alabama, Missouri, Kentucky, Tennessee and Pennsylvania.

In December, a 64-year-old woman searching for her cat was found dead in Westmoreland County, Pennsylvania, several days after she fell into a sinkhole that authorities said was most likely caused by mine subsidence.