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Map of where the earthquake struck at 4:55 am on Nov. 30. (courtesy of the KMA)

At 4:55 am on Thursday, the Korea Meteorological Association sent a mass emergency text to the country, which surely caught many by surprise. Shortly after, a 4.0 magnitude earthquake hit southeastern Gyeongju, South Gyeongsang Province, which registered a Grade 3 seismic intensity. Although no buildings collapsed and nobody was killed or hurt, many people surely recalled the quake that hit Gyeongju back in 2016.

Earthquakes are becoming more frequent. As of the end of November, South Korea experienced 99 earthquakes of 2.0 magnitude or higher so far in 2023. That means 2023 is the year with the fourth largest number of quakes since 1978, when the KMA began collecting seismic data.

Earthquakes that hit the Korean Peninsula started becoming more common in the late 1990s, numbering over 30 annually. This number exploded in the period between 2016 (252 quakes) and 2018 (115 quakes). This reduced to 68-88 in the period following 2019, but it is likely to shoot up to over 100 in 2023. As the frequency of earthquakes increases, so is the frequency of quakes of 3.0 magnitude or higher.

This makes the recent Gyeongju quake particularly notable. Gyeongju was where a 5.8 quake hit on the evening of Sept. 12, 2016, the largest to ever hit South Korea. The second largest was a 5.4 quake that hit the following year in November in Pohang, a city not too far from Gyeongju. Ulsan, also in the same region, experienced a 5.0 quake just two months before the Gyeongju quake in 2019. In short, all of Korea’s 5.0 magnitude quakes are occurring in a region that has the highest concentration of the country’s nuclear power plants.

Research commissioned by the Ministry of the Interior and Safety since 2017 has revealed that the Kori and Wolsong nuclear power plants are near five active faults that could produce quakes that would affect their structural integrity. These faults are referred to as “faults for consideration in seismic design.”

Korea Hydro and Nuclear Power, a subsidiary of the Korea Electric Power Corporation, published the results of this research this past March. The research indicates nuclear plants “within a 32 km radius of active faults that are 1.6 km or longer.” What’s disturbing is that the plants’ engineers did not consider the active faults in their safety designs. The “History of the Three Kingdoms” claims that a quake killed over 100 people in March 779. It’s important to remember that the Gyeongsang region has consistently experienced earthquakes throughout history.

The South Korean government has resumed construction of the Shin Hanul No. 3 and 4 reactors, and is planning on building more. In addition to reinforcing the earthquake resilience of the power plants’ designs to ensure their safety, the government also needs to consult the residents of earthquake-prone regions to gather their opinions on living near nuclear power plants.

The aftermath of earthquakes isn’t limited to nuclear power plants. The South Korean government needs to conduct a serious evaluation of the earthquake resilience of countless buildings and structures, and develop measures for buildings and structures that are not safe. We need to start taking earthquakes seriously, not dismissing them as nothing more than an “emergency alert” text.

Please direct questions or comments to [english@hani.co.kr]