Seoul halts Metro Line No. 9 expansion near sinkhole amid investigation
A motorcyclist who fell into a large sinkhole Monday in Seoul, was found dead after a 17-hour search by authorities, according to officials from Gangdong Fire Station on Tuesday.
The 34-year-old motorcyclist, identified by his last name of Park, was found at 11:22 a.m., about 50 meters away from where the sinkhole formed, according to a Gangdong Fire Station official. After finding Park's body, police and fire authorities along with the Seoul Metropolitan Government, embarked on identifying the cause of the sinkhole.
“Rescue operations were very difficult for authorities, as the soil was heavily mixed with water and heavy equipment from a nearby construction site was all entangled with one another,” fire authorities told the press Tuesday.
“Authorities were able to identify Park only after the area was drained of water and the soil was removed using heavy machinery. ... We deeply regret that we couldn't bring better news and we offer our condolences to the deceased."
At 6:29 p.m., Monday, a 20-meter-wide and 18-meter-deep sinkhole suddenly formed near an intersection in Gangdong-gu, eastern Seoul, swallowing the motorcyclist and injuring the driver of a car that passed over the sinkhole just before its collapse.
According to the Seoul Metropolitan Government, 17 rescue workers and one rescue dog were deployed to find the missing motorcyclist.
Water pipes running underneath the road burst as the sinkhole formed and caused flooding, prolonging search operations for the missing motorcyclist. To prevent more water from pouring into the waterworks system and flowing further into the sinkhole, the water supply was shut off by authorities in areas near the intersection.
During overnight search operations, authorities found a mobile phone presumed to belong to the motorcyclist inside the hole at 1:37 a.m. At 3:30 a.m., a motorcycle was also found inside, approximately 30 meters inside the sinkhole.
Authorities resumed search operations by using heavy equipment such as excavators to dig through the soil inside the sinkhole. Fire authorities told the press that the sinkhole had initially contained about 2,000 metric tons of water mixed with 6,480 tons of soil. Most of the water was drained overnight using pumps, and rescue personnel dressed in diving suits used shovels to remove soil.
Due to safety concerns, four schools in the area, including Seoul Daemyeong Elementary School, Hanyoung Middle and High schools and Hanyoung Foreign Language High School, were temporarily closed on Tuesday. The authorities cut off electricity in nearby areas and removed all oil tanks at a nearby gas station as precautions against potential accidents from road vibrations caused by soil removal work inside the sinkhole.
Construction work to extend Seoul Subway Line No. 9 was also underway near the accident site. The city government announced it would temporarily suspend all construction, noting that the project cannot be ruled out as a possible cause of the forming of the sinkhole.
At 9:20 p.m. on Monday, Seoul Mayor Oh Se-hoon also visited the accident site to be briefed by officials on the details behind the incident and the response measures taken by authorities.
On Tuesday, the Seoul Metropolitan Government also hosted an emergency meeting to discuss the ongoing rescue efforts and post-accident, preventive measures the city government should take.
During the emergency meeting, Oh stated that the city government would help conduct a “thorough investigation to determine the cause behind the incident.”
Meanwhile, according to the city government, the site of the sinkhole underwent a special inspection by the Ministry of Land, Infrastructure and Transport in December 2024 as it was classified as a major construction zone due to the expansion of the Seoul Subway Line No. 9.
Though ground penetrating radar surveys were conducted at the time, no underground voids were detected.
A regular inspection commissioned by the city in June 2019, which takes place every five years, had also found nothing abnormal, according to the city government.
However, according to local media reports, multiple complaints had been made to the city government and to Gangdong-gu Office earlier this month regarding cracks forming in the ground of the gas station near the sinkhole. Though inspections were conducted after the complaints were made, nothing abnormal in monitoring data and no signs of ground subsidence was found up until the day of the accident, according to the city government.
As the cause of the sinkhole is still under investigation, the city government will join a joint investigation team with relevant experts and agencies to determine the exact cause. In addition, additional GPR surveys will be conducted around other major subway construction sites in the city — like the Dongbuk Line, Wirye Line and the underground complex development project at Yeongdong-daero — to check for possible ground subsidence.
lee.jungjoo@heraldcorp.com
