Focal Mechanism in and Around the Korean Peninsula

In and around the Korean Peninsula, 18 intraplate earthquake focal mechanisms since 1936 were analyzed to understand the characteristic of focal mechanism and regional stress orientation and tectonics. These earthquakes are largest ones from the last century and may represent the characteristics of earthquake in this region. Focal mechanism of these earthquakes show predominant strike-slip faulting with small amount of thrust components. The average P-axis is almost horizontal ENE-WSW direction. This mechanism pattern and the direction of maximum stress axis is very similar with northeastern part of China and southwestern part of Japan. However they are quite different with the eastern part of East Sea. This indicate that not only the subducting Pacific Plate from east but also the indenting Indian Plate controls focal mechanism in the far east of the Eurasian Plate.