Disaster occurrence

Earthquake

magnitude : magnitude : ML=5.8

The Korean peninsula, a part of the Eurasian plate, shows the characteristics of intraplate seismicity. The level of seismicity is quite lower than that in the neighboring parts of Northeastern China and Japan. However, 14 events of damaging earthquake (estimated larger than M 6.4) have been recorded during the past 2000 years. Many of these earthquakes occurred around the Gyeongju-Ulsan area, some of which caused fatalities and produced liquefaction. Active fault study in Korea was first started by joint work with Japanese researchers (e.g. Okada et al., 1994). However, due to the lack of Quaternary deposits, unclear surface topographic expressions and low slip rate, Korean active fault study was restricted in local areas. Some paleoseismological data from trench logs along the Yangsan and Ulsan fault systems give important information about the fault movement in Late Quaternary. The Korean government launched the new project for the national active fault map. The main aims of this project are 1) making the Korean Active Faults Map based on investigation and research on active faults, and 2) standardization of the investigation and evaluation techniques for Korean active faults. It will take total 25 years (2017~2041, 5 stages) starting from the southeastern part of the Korean peninsula, where the 9.12 Gyeongju earthquake (ML=5.8; 12th September 2016) occurred. The research results on paleoseismology associated with Korean active faults will give important input parameters for making probabilistic seismic hazard map (PGA & SA) and establishing the national seismic performance levels in Korea. It also contributes to the national prevention plan for the mitigation of earthquake disaster.