Last Year 70 Earthquakes of Magnitude 2.0 or Higher... Seogwipo's Magnitude 4.9 Earthquake Was the Largest

Two Earthquakes of Magnitude 4.0~5.0 Occurred Last Year
Jeju Earthquake Recorded as the 11th Largest Ever
Over 200 Aftershocks in 2016~17, Decreasing Annually Due to Fewer Aftershocks

[Asia Economy Reporter Han Jinju] More than 70 earthquakes with a magnitude of 2.0 or higher occurred on the Korean Peninsula last year. As aftershocks from the Pohang earthquake decreased, the number approached the annual average.

On the 27th, the Korea Meteorological Administration (KMA) published the "2021 Earthquake Yearbook," which contains an analysis of domestic earthquakes in 2021. It includes analysis results of earthquakes with a magnitude of 2.0 or higher, intensity distribution maps, and detailed information on seismic observation stations.

Last year, two earthquakes with magnitudes between 4.0 and 5.0 occurred. The largest was a magnitude 4.9 earthquake that occurred on December 14 in the sea area 41 km southwest of Seogwipo, Jeju. Since instrumental observation began in 1978, it was the 11th largest in magnitude, and seismic waves were transmitted as far as Jeollanam-do and Gyeongsangnam-do. The second largest was a magnitude 4.0 earthquake that occurred on August 21 in the sea area 124 km southwest of Eocheongdo, Gunsan-si, Jeollabuk-do.

There were a total of 70 earthquakes with a magnitude of 2.0 or higher on the Korean Peninsula last year, which was similar to the annual average (70.6 times). Earthquakes with a magnitude of 3.0 or higher occurred five times, the same as in 2020, and fewer than the annual average (10.8 times).

By year, earthquakes with a magnitude of 2.0 or higher were only 44 times in 2015 but increased significantly in 2016 (252 times) and 2017 (223 times). The numbers surged in 2016 and 2017 when the Gyeongju and Pohang earthquakes occurred, then decreased to 115 times in 2018, 88 times in 2019, and 68 times in 2020.

In South Korea, earthquakes with a magnitude of 2.0 or higher by region were observed 7 times in Busan, Ulsan, and Gyeongsangnam-do; 5 times in Daegu and Gyeongsangbuk-do; 5 times in Jeollabuk-do; and 0 to 2 times in other regions.

Small earthquakes with a magnitude below 2.0 were recorded 201 times in Daegu and Gyeongsangbuk-do, 44 times in Daejeon, Chungnam, and Sejong, 42 times in Chungbuk, and 39 times in Busan, Ulsan, and Gyeongsangnam-do, in that order.

The KMA issued an early warning just 12 seconds after the first detection of an earthquake and sent out disaster alert messages. This was the fastest announcement since the earthquake early warning service began in 2015. During the 2016 Gyeongju earthquake, the warning was issued in 26 seconds, and during the 2017 Pohang earthquake, it was issued in 19 seconds.

Park Kwang-seok, head of the KMA, emphasized, "Earthquakes with a magnitude of 5.0 or higher, which can cause significant damage, can occur anywhere in our country, so thorough monitoring and preparedness are always important."

This content was produced with the assistance of AI translation services.