A map showing the epicenter of the earthquake southeast of Gyeongju, North Gyeongsang Province. (Korea Meteorological Administration)

A 4.0 magnitude earthquake occurred in the early hours of Thursday, 19 kilometers southeast of Gyeongju, North Gyeongsang Province, the Korea Meteorological Administration said.

According to the KMA, the initial earthquake occurred at about 4:55 a.m., followed by five tremors ranging up to 1.5 magnitude until 5:50 a.m.

The earthquake led to emergency national disaster alert across the country being sent out about 8 seconds after the event was detected.

No reports of damages or injuries have been filed to the authorities as of 7 a.m.

This is the 99th earthquake over 2.0 magnitude to have occurred in Korea this year. Thursday’s earthquake is the second strongest this year after the 4.5 magnitude earthquake detected off the east coast of Gangwon Province on May 15.

According to data, Korea has seen an average of 70.6 earthquakes over 2.0 magnitude since 1999.