A 5.1-scale earthquake occurred off the southwestern coast of Korea near Taean, South Chungcheong Province on Tuesday morning. It was the fourth-strongest quake on the Korean Peninsula since statistics began in 1978.
The Korea Meteorological Administration said the quake occurred in the West Sea around 100 km northwest of Taean at 4:48 a.m. A minor quake measuring 2.3 on the Richter scale occurred in the same area at 9:25 a.m.
The quake caused windows to rattle in the Taean area, and even people in some parts of Seoul could feel mild tremors.
Residents were startled early in the morning, with some thinking the tremors were due to North Korean artillery shelling. The Seoul Metropolitan Fire and Disaster Headquarters and police hotline received around 130 calls from people inquiring about the tremors and the Gyeonggi Fire and Disaster Headquarters 150.
In 1980, a 5.3 quake hit the North Korean city of Uiju in North Pyongan Province, while 5.2 quakes rattled Uljin, North Gyeongsang Province in 2004 and Mt. Sogni in North Chungcheong Province in 1978.
There has been increased seismic activity around the Korean Peninsula recently. The KMA recorded 93 quakes of more than 2.0 on the Richter scale last year, the most in a single year in this region.
Earthquakes measuring 4.9 shook Baeknyeong Island in the West Sea and Sinan, South Jeolla Province in April and May last year.
Seismologists are concerned and warn a massive trembler measuring more than 6.0 could hit the region.