[Inside Chodong] A Decade Lost with a 'Time Bomb' Beneath Our Feet

Watching the recent spate of accidents caused by sinkholes, I was reminded of a report published a decade ago by the Korea Infrastructure Safety Corporation. The report, titled "A Study on the Development of Manuals for Signs and Safety Management in Everyday Life to Prepare for Ground Subsidence," was created in response to concentrated ground subsidence incidents around Seokchon Lake in Songpa-gu, Seoul in 2014, urging the authorities to come up with countermeasures.

Let's look at the contents of the report. At the time, the report pointed out to the government and local authorities that "there is no comprehensive legislation in Korea governing the use of underground spaces, including ground and geological matters," and that "information related to the ground is managed separately and in a fragmented way by relevant agencies and local governments." It also stated that "there are limits to policy development for the safe use of underground spaces," emphasizing the need for an overarching control tower. Ten years have passed since then, but nothing has changed. The report analyzed the causes of ground subsidence, and the causes of the recent subsidence accidents in Myeongil-dong, Gangdong-gu and Gwangmyeong, Gyeonggi Province, are identical to those analyzed in the report a decade ago.

The response systems of local governments and the central government have also remained unchanged. Last week, a document sent by the Ministry of the Interior and Safety to Seoul City and others contained only general recommendations such as "suspend work upon detection of abnormal signs" and "repair and reinforce aging underground facilities." While there is an "awareness" that repeated accidents are a problem, there is no "will" to establish fundamental countermeasures.

How did advanced countries spend the same ten years? The United States and Japan incorporated the risk factors identified in ground subsidence accidents directly into their response systems. In the United States, since 2010, ordinances related to ground subsidence have been enacted, and the issue has been addressed in depth as a policy matter. The U.S. has even established grading standards for construction and building methods that affect ground subsidence. The state of Florida made it mandatory to provide insurance products that cover damages from ground subsidence through legislation and related insurance companies.

Tokyo, Japan has also responded quickly to ground subsidence. After a series of ground subsidence problems in the 1970s and 1980s, Japan advanced its detection technology and revised related regulations. In particular, Tokyo conducts annual ground subsidence surveys, and its technological capability to respond to ground subsidence through research and development is now considered among the best in the world. Special vehicles capable of detecting underground spaces at depths of 1 to 3 meters are in operation, and when a road collapsed during underground construction in Shibuya in the past, the system was able to predict the collapse and prevent casualties.

This is why, even though it is late, there is a need to establish management measures for underground voids. Seoul City is reportedly considering conducting geological surveys of large excavation sites to create safety maps. All underground facilities?including subways, water and sewage pipes, communication ducts, power lines, and heating pipelines?must be inspected to build a comprehensive database of underground conditions. The inspection cycle also needs to be adjusted. Rather than only investigating areas where ground subsidence has already occurred, it is necessary to establish a real-time automatic monitoring system that can assess risk in advance. Although the city is said to be pushing for the establishment of a "ground subsidence monitoring network," even the pilot project could take several months.

However, simply releasing a "priority maintenance zone map" in response to public pressure requires careful consideration of its effectiveness. Although the map is said to be created using information about ground conditions and underground facilities, the lack of verification processes such as geological surveys or laser scanning could potentially cause more confusion. It is fortunate that 130 billion won has been allocated for sinkhole prevention in this year's first supplementary budget. While it may not be possible to solve all the accumulated problems at once, authorities must at least demonstrate their determination not to create a world where people have to worry about the ground collapsing beneath their feet.