Study on the characteristics of earthquake with fault distribution in the western area of the Ulleung Basin, East Sea (Japan Sea)

Abstract

We performed a comprehensive research on fault characteristics, tectonic environment and evolution, earthquake generation mechanism, and characteristics of earthquakes with magnitudes, by analyzing geophysical data, especially seismic data, on the Korean peninsula and surrounding seas subsequently drawing a fault distribution map.The tectonic lines associated with the past tectonic motions are linked to recent earthquake events. Earthquakes caused by strike slip faults and reverse faults are densely distributed along the steep slope of the eastern and southern part of Ulleung basin in N-S direction or NE-SW direction. The earthquake activities in this region are linked to the compression of the crust. As a result of the local compressive force, the southern part of Ulleng Basin is characterized by uplifts and thrust faults along Dolgorae trap in the Late Miocene.According to the epicenter distribution from the KMA (Korea Meteorological Administration), earthquakes were widely and diffusely distributed over the inland area of the Korean peninsula. However, several earthquake swarms have occurred in the specific areas of surrounding seas. The epicenters of earthquakes with magnitude greater than 3 tended to be located along the existing fault zones in both time and space.A study on seismic characteristics utilizing the seismic data, along with an identification of fault zones using the epicenter distributions of on the Korean peninsula and surrounding seas subsequently drawing a fault distribution map.The tectonic lines associated with the past tectonic motions are linked to recent earthquake events. Earthquakes caused by strike slip faults and reverse faults are densely distributed along the steep slope of the eastern and southern part of Ulleung basin in N-S direction or NE-SW direction. The earthquake activities in this region are linked to the compression of the crust. As a result of the local compressive force, the southern part of Ulleng Basin is characterized by uplifts and thrust faults along Dolgorae trap in the Late Miocene.According to the epicenter distribution from the KMA (Korea Meteorological Administration), earthquakes were widely and diffusely distributed over the inland area of the Korean peninsula. However, several earthquake swarms have occurred in the specific areas of surrounding seas. The epicenters of earthquakes with magnitude greater than 3 tended to be located along the existing fault zones in both time and space.A study on seismic characteristics utilizing the seismic data, along with an identification of fault zones using the epicenter distributions of