Echoes of the Devastating Umyeonsan Landslide... Retaining Walls Prove Useless

[Anchor]

The recent landslide in Geoje, South Gyeongsang Province, triggered by heavy downpours, bears a striking resemblance to the deadly Umyeonsan landslide in Seoul 15 years ago. Both disasters saw torrents of mud instantly crash through the ground-floor units of apartment complexes. In the latest incident, a retaining wall was present, but it failed to serve any purpose at all.

For Morning Zoom-In, here is reporter Yoo Soo-Hwan.

[Reporter]

In the early morning of July 27, 2011, a landslide on Mount Umyeonsan in Seocho-gu, Seoul, swept through an apartment complex in an instant, claiming 16 lives.

Similarly, the recent landslide in Okpo-dong, Geoje, which left one person dead and two injured, occurred at 4:30 a.m., giving residents no time to escape.

[Ahn Jae-hu / Resident of the Geoje Landslide Apartment: Mud burst right through the house, debris was visible, and two people were trapped under the rubble on the first floor.]

The mud that struck the rear of the apartment penetrated the ground-floor units and broke straight through the common entrance. Mud saturated with water, measuring 1 meter in width, length, and height, weighs around 1.5 tons per cubic meter, equivalent to a passenger car.

Flowing down a slope, it strikes with a force equivalent to a speed of 11 kilometers per hour. In the case of a landslide, this means a mass of soil equivalent to anywhere from dozens to around 100 cars comes crashing down in an instant.

Notably, the Geoje landslide occurred on the steep slopes of Mount Guksabong, located directly behind the apartment complex.

Although fences and retaining walls were installed on the mountain slope to prevent falling rocks, they proved completely useless in the face of such extreme downpours.

[Official from Geoje City Hall: The retaining wall where the mud slid down was only about 1.5 to 2 meters high...]

Experts point out that when apartment complexes are built by cutting into mountains, sufficient buffer distances must be maintained, and retaining walls should be installed differently depending on the characteristics of the mountain.

[Park Chang-kun / President of the Korea Authority of Land and Infrastructure Safety (Former Professor at Catholic Kwandong University): (Regarding retaining walls) it is necessary to strictly distinguish and design them based on whether it is a rocky mountain or a soil mountain, and if necessary, make the retaining walls significantly higher...]

[Lee Young-joo / Professor, Department of Fire and Disaster Protection, Kyungil University: It is preferable to secure a sufficient buffer distance and build with enough space to physically absorb the impact.]

During the Umyeonsan landslide, large amounts of water-logged soil also poured into apartments and residential areas, but there were no facilities to stop it.

According to statistics from the Ministry of the Interior and Safety, out of 160 deaths and disappearances caused by heavy rain over the past 10 years, casualties from landslides accounted for the largest share at 75 people.

(Photo: Yonhap News) (Video Journalist: Kyungmun | Video Editor: Seeun)
※ Please note: This article was translated by AI and may contain errors.