The issue of disclosing the Seoul Metropolitan Government's “ground subsidence safety map” in connection with last month's sinkhole accident in Gangdong-gu, Seoul, is expected to turn into a court battle. While civic groups are calling for the release of the map, the city maintains that “it cannot be released because it is classified and irrelevant to the sinkhole.”

On April 9, the New Seoul Preparation Special Committee of the Democratic Party of Korea (DPK) held a press conference, urging the city to “release the safety map in order to uncover the causes of the sinkhole incident in Gangdong-gu.”

According to the special committee, the Center for Freedom of Information and Transparent Society, the Korean Public & Social Services and Transport Workers' Union, and others requested the city to release the ground subsidence safety map on April 2, but was denied. The organizations filed an appeal on the 7th and plan to pursue administrative litigation if the city’s Information Disclosure Review Board upholds the non-disclosure decision. “The U.S. state of Florida releases its sinkhole map so that residents can identify sinkhole risk areas, and Tokyo, Japan, shares risk information on sewer pipes and underground spaces with citizens,” the special committee said, arguing that Seoul should also release the safety map.

Park Joo-min, head of the New Seoul Preparation Special Committee, said, “The U.K. and Germany also make geological data and maps of underground utilities publicly available. In Korea, the Ministry of the Interior and Safety discloses various public safety maps about flood-risk areas, crime-prone areas, and aging buildings. There’s no reason for Seoul to withhold the ground subsidence safety map.”

However, Seoul continues to maintain its stance against disclosure. The city argues that the map in question was not created to assess sinkhole risk and that it falls under the Basic Act on National Spatial Data, making it legally restricted from being made public.

“The map was created for internal management purposes to improve the efficiency of Ground Penetrating Radar (GPR) exploration, and does not represent a risk rating,” a city official said, adding that disclosure would create unnecessary misunderstanding and anxiety. The official added, “Underground spatial information is subject to disclosure under the ‘Seoul Metropolitan Government's Rules for Handling Geospatial Information Security Work’ under Article 35 (Security Management) of the Basic Act on National Spatial Data.”

However, experts agree that disclosure is necessary. “If you look at Japan, for example, they create safety maps for floods and actively inform villages, drawing residents' participation and attention to safety monitoring activities,” said Park Chang-geun, a professor of civil engineering at Catholic Kwandong University. “If there is sensitive information (as claimed by the city), it is possible to redact such parts and disclose the degree of danger, as citizens are anxious.”

“The prioritized maintenance zone map that the Seoul Metropolitan Government is talking about and the safety map requested by civil groups are virtually the same, with only a different name,” said Lee Chan-woo, president of the Korea Tunnel Environment Society. “GPR inspections are conducted to prevent possible ground subsidence risks, which is consistent with the safety map.” He added, “Sinkholes are accidents that can be prevented with proper construction and good management and supervision. The city’s tendency to conceal information is only heightening public anxiety.”

The New Seoul Preparation Special Committee also emphasized, “According to the Framework Act on the Management of Disasters and Safety, safety-related information must be made public and accessible to everyone.” It urged, “The Ministry of Land, Infrastructure and Transport, which oversees underground safety, should work with the city to reform laws and systems to mandate the disclosure of ground safety information.”

The sinkhole incident in Gangdong-gu has continued to spark controversy over whether it was a man-made disaster, as it occurred near a construction site of Seoul Subway Line 9. In 2021, the Korea Tunnel Environment Society sent an official letter to the city warning that the area required caution due to its proximity to the underground tunnel for the Seoul-Sejong Expressway in the district. At the time, the Seoul Metropolitan Government forwarded it to the contractor, but it is understood that no further preemptive measures were taken to prevent ground subsidence.