An image, captured from the website of the Korea Meteorological Administration, shows the epicenter of a quake that hit Korea's central city of Chungju, Feb. 7. Yonhap

A 3.1-magnitude earthquake struck South Korea's central city of Chungju early Friday, the state weather agency said, prompting the government to operate a disaster management body and issue the second highest quake alert.

The Korea Meteorological Administration (KMA) said that the quake took place in an area 22 kilometers northwest of Chungju's city hall in North Chungcheong Province, at 2:35 a.m. The epicenter was located in the town of Angseong, with a depth measured at 9 kilometers.

There were no reports of serious injuries or damage, according to the Ministry of the Interior and Safety.

The KMA initially put the magnitude of the quake at 4.2, but revised its strength down to 3.1. This week's quake is the strongest among seven quakes that have struck the Korean Peninsula this year.

Soon after the quake, the authorities operated the Central Disaster and Safety Countermeasure Headquarters (CDSCH) and issued a quake alert level of "vigilance." The four-tier alert system consists of four levels roughly translated as "attention," "caution," "vigilance" and "seriousness."

Acting Interior Minister Ko Ki-dong, CDSCH chief, ordered relevant government agencies and provincial authorities to maintain an emergency response system and swiftly assess any damage from the latest quake.

According to the ministry, there were 23 reports from people who said they felt the quake, including 13 reports from Gangwon Province and eight from North Chungcheong Province. (Yonhap)