Recent Earthquake Activity in and around Kyeongsang Basin

최근의 경상분지 일원에서의 지진활동

To understand the current seismic activity and regional tectonic status in and around Gyeongsang basin, Korea Institute of Geology, Mining, and Materials(KIGAM) has performed the earthquake monitoring around the Gyeongsang basin since early 1980's with portable analog seismic instruments for about two months every year. As a part of POSEIDON project, Korea-Japan joint observation around gyeongsang basin in 1991 and 1992, was performed using by temporary seismic station. KIGAM has been continuously operated nine short-period 3-components digital seismic stations since the end of 1994. During the observation period, 247 earthquakes were analyzed and their magnitude was less than 4.5. In general, we could not find any relationship between seismic activity and known surface geological features. But the epicenters were rather concentrated with NW-SE direction. The most active seismicity was found in Gyeongbuk Gyeongjugun Seokeupri and Hyodongri, and Yeongilgun Janggiri and Guryongpo in land, and in three region along the east coast which are 10km and 30km east off from Gampo and 30km east off from Jongja in offshore.