The photo shows a massive sinkhole on a road in Gangdong-gu, Seoul, on March 25. Reporter Lee Jun-heon

A man in his 30s was found dead after falling into a massive sinkhole in Myeongil-dong, Gangdong-gu, Seoul.

Police and the Seoul Metropolitan Government have launched an investigation into the cause of the sinkhole along with cleaning up the accident site. Gangdong Fire Station said in a briefing on March 25, "We found Park (34) in a state of cardiac arrest who fell into a sinkhole at around 11:22 a.m. and was buried there." A fire official said, “We found him around 50 meters from the centerline of the sinkhole,” adding, ”He was buried at a depth of 90 centimeters.” Earlier in the day, fire authorities found Park‘s cell phone and motorcycle. Park had reportedly started delivery work on the side a few years ago after his business became difficult.

A massive sinkhole on a road in Seoul is pictured on March 25. Reporter Lee Jun-heon

Park had fallen into the 20-meter-diameter sinkhole that suddenly occurred at around 6:28 p.m. the previous day while riding his motorcycle along the road which passes above a tunnel construction site for Subway Line 9. A van running in front of Park’s motorcycle narrowly avoided a plunge, and the driver, Heo (48) was treated for minor injuries. About four to five workers were away from the subway construction site and escaped the accident.

It took a long time to find Park because the search area was wide and deep as the lower part of the sinkhole connected to a tunnel at the subway construction site. The sinkhole occurred at a depth of 11 meters, and the upper part of the tunnel at the construction site of between 7 and 9 meters high at the bottom also collapsed, making the depth from the ground to the bottom of the sinkhole about 20 meters. The sinkhole led to a 160-meter-long tunnel section of the subway construction site. This is where Park was thought to have fallen, but a water supply pipe burst, releasing about 2,000 tons of water and filling the tunnel with mud. Even after the drainage work was completed, the rescue took longer as heavy equipment related to the construction got tangled in the tunnel and the mud hardened.

Firefighters used shovels to dig through the mud and heavy equipment, including two excavators, to scrape away the mud. At one point, the rescue operation was halted for safety reasons when a crack was discovered near the ceiling of the sinkhole. Only after stabilizing the slope of the sinkhole could the search continue.

A Seoul city official said, "We are reviewing a recovery plan, but the specific timing of the recovery remains to be seen as the cause must be investigated, first.” When asked if there were signs of a sinkhole even before the accident, such as cracks in the ground on a nearby road, the official said, “We received a complaint, investigated it on the 20th, and confirmed that there was no abnormality in the ground subsidence. Afterward, we installed a measuring instrument and continued to check, but there was no problem.” The official added, "We have not ruled out the connection with the subway construction. We will thoroughly investigate and analyze the cause." A police official said, “To investigate the cause of the accident, we have begun a pre-prosecution investigation against the subway construction contractor and others,” adding, “We will investigate the cause without limiting the scope, beyond the subway construction.”

Residents in the neighborhood could not hide their anxiety. In particular, parents complained of anxiety as there are three elementary schools, one middle school, and four high schools within a 1-kilometer radius of the sinkhole. Four schools, including Hanyoung Middle and High Schools, Hanyoung Foreign Language High School, and Daemyung Elementary School, were closed for the day. Jeon (39), who was taking her child to elementary school, said, "I knew where it was just by looking at the pictures because it was a road I used often to go out with my children every weekend. I know that the subway construction under the accident site takes about four years, and I'm worried that the accident will happen again."