2) The History of Earthquakes in Korea

Geologically, the Korean peninsula consists in large part of “Precambrian rocks, most soils derived from granite and gneiss. With all the geological aspects, Korea is located in the safe zone beyond the “Ring of Fire.” Thus, Korea is believed to be laid on the area of low seismicity. However, there have been warnings of the major earthquakes based on the numerous historic records showing seismic activities in the region of south eastern part of the peninsula. “The first earthquake reported in the ancient history of the Korean peninsula occurred in A.D. 2, in August of the 21st year of King Yuri of Goguryo Kingdom. According to Korean history books, before the first seismometer was installed in Inchon in 1905, nearly 1,800 earthquakes happened in Korea: they were felt by most people living here. The most destructive earthquake in Korean history occurred in A.D. 779 during the Silla Kingdom. At least 100 people died as homes collapsed when a massive earthquake hit the ancient city of Gyungju.”(Ilyeon)  There is also a proof of earthquake occurrence in Joseon Dynasty. Thus the Annals of the dynasty chronology mention “eight consecutive earthquakes occurred in the Hamgyong Province from Aug 26th to 28th, 1597. The walls quaked and collapsed, frightening birds and animals. Many people became sick in bed.” (Annals of Joseon Dynasty, 1597). In this chronology there is a report “In 1680, a staff member of the National Weather Service was arraigned in criminal court for failing to make timely reports on earthquakes” (Annals of Joseon Dynasty,1680)

 Since the opening of the 20th century, there have been four significant earthquakes recorded in Korea which magnitude was greater than 5.0. In December 1996, the earthquake with magnitude 4.5 stroke the Yong Wol area located in the mid east of Korea, spreading impact on the whole Korean peninsula. In June 1997, the Kyung Ju earthquake with magnitude 4.3 concerned many people because its epicenter is located on Yong San Fault which is regarded as a potential active fault. The Yong San fault is one of the latest major faults developed in the Korean peninsula. It is about 200km long and located in the South Eastern part of Korea which has been regarded as potential major earthquake occurrence district. The strongest earthquake since the opening of the 20th century happened in Pyungbook, North Korea in 1980 which was measured magnitude 5.3. Recently, there was another strong earthquake in Uljiu, Kyungbook, South Korea in 2004.

    After all, the Korean peninsula is one of the long historical districts with rich earthquake information in relation to abundant accounts of the historic events. Consequently, Korea is in a way has provided beneficial conditions for studying the historical earthquakes in the north eastern Asia. Obviously, the historical earthquake data can be an important foundation for seismic monitoring, earthquake forecast, and seismic safety evaluation. In short, the work of earthquake prevention and hazard mitigation can be benefited from the study of the earthquake occurrence in the Korean history. 

In this figure, the red arrow refers to the force from four plates such as Amurian Plate, Okhotsk Plate, Philippine-Pacific Plate, and Southern China Plate. The black arrow refers to the force and direction observed by GPS (Global Positioning System). The black arrows are found in Gang Reung (the most upper part), Gwangju, Jeonju, Daegu ( From left to right). The dotted arrow explains the estimated epicenter of the peninsula.