Tectonic interpretation of seismic characteristics of earthquakes around the Korean Peninsula

Abstract:

The region around the Korean Peninsula appertains to an intraplate zone, where is under the compressional tectonic regime due to the compressional stress field induced from the collisions of the Eurasian plates with surrounding plates. In such an intraplate zone, the strike-slip faulting earthquakes are typically expected. However, unusual thrust faulting earthquakes occurred in the marginal zones of the East Sea (Sea of Japan) and normal faulting earthquakes occurred within the narrow zone around the central Yellow Sea. High seismicity of reverse faulting events is observed in the marginal zones of the East Sea, the southeast offshore zone of the Korean Peninsula and west offshore zone of the Japanese Islands. Such observation in the East Sea is interpreted to be the reverse activation of paleo-normal faults that were developed during the opening of the East Sea. On the other hand, the ENE-WSW directional normal faulting earthquakes are observed in an ENE-WSW directional narrow zone between the Shandong Peninsula and central Korean Peninsula across the Yellow Sea. The normal faulting zone is interpreted to be the northern margin of the collision belt in the Yellow Sea, which may be extended to the Korean Peninsula across the Yellow Sea.