Following a landslide triggered by record-breaking downpours on the 17th in Geoje, South Gyeongsang Province, which left one person dead and two injured, experts are pointing out the urgent need for thorough safety inspections on residential areas located beneath mountains, noting that a similar accident occurred in Geoje six years ago.

According to Geoje City and other sources yesterday (the 18th), a landslide occurred on the morning of September 7, 2020, when the slope in front of Building 106 of an apartment complex in Mundong-dong gave way due to heavy rain.

At that time, affected by rain clouds brought by Typhoon Haishen, Geoje was pounded by 189 millimeters of rain from midnight on September 6 to 9 a.m. on September 7.

Hundreds of tons of earth and mud poured toward the apartment complex accompanied by loud thunder, damaging multiple vehicles.

Fortunately, residents evacuated after hearing the management office announcement, preventing casualties, but about 90 people had to evacuate urgently.

The latest landslide similarly occurred when earth and mud on a cut slope around an apartment built at the foot of a mountain could not withstand the torrential rain.

The sudden accident occurred at 4:42 a.m. when most residents were asleep, killing a person in their 20s living on the first floor, while two others living on the first floor were rescued by dispatched fire authorities and others.

During the landslide, Geoje received more than 700 millimeters of torrential rain over the three-day Liberation Day holiday.

In particular, extreme downpours exceeding 400 millimeters battered the area between the night of the 16th and the early hours of the 17th, causing heavy damage in various places.

Behind Building 104, where the accident occurred, there was a retaining wall to prevent landslides, but it was only 1.5 meters high.

This apartment, completed in 1994, received a Grade B rating in a safety inspection conducted last July.

It is reported that no particular abnormalities were found during the safety inspection at the time, including the condition of the retaining wall.

An official from Geoje City stated, "We believe there are no structural problems as the height of the retaining wall was designed taking into account the stress capable of receiving earth pressure," adding, "While safety inspections typically check the condition of retaining walls, inspecting the underlying ground is a stretch."

The location of the recent accident turned out to be an area with a high risk of landslides.

According to the landslide information system operated by the Korea Forest Service, this area includes multiple Grade 1 zones on the landslide hazard map.

The landslide hazard map predicts the probability of landslides based on past landslide occurrences and topography, analyzed in 100-square-meter grid units and divided into five grades.

However, this location was not included in the designated landslide-vulnerable areas where the government takes preventive measures for places expected to suffer damage from landslides.

The problem is that a large number of apartments in the Geoje region are built around mountains and cut slopes, just like the site of this accident.

About 70 percent of Geoje's total island area consists of slopes, with very steep mountainous terrain forming the center of the island.

As a result, many apartments and roads have been built by cutting or reclaiming the slopes at the lower parts of mountainous areas.

This means the slopes are structured to easily collapse when torrential rains pour down, as seen in this case.

Gyeongnam Governor Park Wan-su, who visited the accident site on the day of the incident, pointed out during an emergency countermeasures meeting held at the provincial office on the 18th, "It is incomprehensible that an apartment was built on what is practically a sheer cliff," adding, "There is a concern for additional landslides."

Experts advise that landslide forecasting systems need to change in response to increasingly severe abnormal climate conditions.

Kim Dong-yup, a professor of forest resources at Daegu University, said, "Because landslide forecasting systems are built based on past cases and rainfall information, blind spots can occur in current situations where the climate environment is changing." He added, "We need to supplement the forecasting system to fit situations with extreme downpours that happen once in 200 years, like this time, while residents living in hazard areas should also raise their awareness of safety accidents to prevent them together."