A 5.1 magnitude earthquake shook the nation at 4:48 a.m. Tuesday morning, with an epicenter in waters around 1-hundred kilometers west of Taean county in Chungcheongnam-do province.
It's the fourth most powerful earthquake ever recorded on the Korean peninsula, and the third strongest in South Korea.
Tuesday's quake lasted between 5 and 7 seconds and affected an area spanning a radius of 2-hundred kilometers, shaking buildings and other structures.
Residents of Seoul and Gyeonggi-do province were among those who felt the Earth move beneath them.
"I was awake. My house shook so much that our refrigerator made rattling noises."
Hundreds of citizens called their local authorities to report the quake, and social network services were full of messages on the rare incident.
It's also raised concerns, about whether Korea is prepared for the possibility of stronger quakes.
While experts say a magnitude-5 quake with an epicenter on land would likely cause damage, they add that Korea's geological site conditions make the chances of a large magnitude earthquake, like those seen in Japan and China, very small.
Kwon Soa, Arirang News.